kernel: update to 4.9.13

[ipfire-2.x.git] / src / patches / linux / linux-4.9.8-layer7-filter.patch

diff -Naur linux-4.9.8.org/include/linux/netfilter/xt_layer7.h linux-4.9.8/include/linux/netfilter/xt_layer7.h
--- linux-4.9.8.org/include/linux/netfilter/xt_layer7.h 1970-01-01 01:00:00.000000000 +0100
+++ linux-4.9.8/include/linux/netfilter/xt_layer7.h     2017-02-10 20:55:36.894611414 +0100
@@ -0,0 +1,13 @@
+#ifndef _XT_LAYER7_H
+#define _XT_LAYER7_H
+
+#define MAX_PATTERN_LEN 8192
+#define MAX_PROTOCOL_LEN 256
+
+struct xt_layer7_info {
+    char protocol[MAX_PROTOCOL_LEN];
+    char pattern[MAX_PATTERN_LEN];
+    u_int8_t invert;
+};
+
+#endif /* _XT_LAYER7_H */
diff -Naur linux-4.9.8.org/include/net/netfilter/nf_conntrack.h linux-4.9.8/include/net/netfilter/nf_conntrack.h
--- linux-4.9.8.org/include/net/netfilter/nf_conntrack.h        2017-02-04 09:47:29.000000000 +0100
+++ linux-4.9.8/include/net/netfilter/nf_conntrack.h    2017-02-10 16:10:27.000000000 +0100
@@ -120,6 +120,22 @@
        /* Extensions */
        struct nf_ct_ext *ext;
 
+#if defined(CONFIG_NETFILTER_XT_MATCH_LAYER7) || \
+    defined(CONFIG_NETFILTER_XT_MATCH_LAYER7_MODULE)
+       struct {
+               /*
+                * e.g. "http". NULL before decision. "unknown" after decision
+                * if no match.
+                */
+               char *app_proto;
+               /*
+                * application layer data so far. NULL after match decision.
+                */
+               char *app_data;
+               unsigned int app_data_len;
+       } layer7;
+#endif
+
        /* Storage reserved for other modules, must be the last member */
        union nf_conntrack_proto proto;
 };
diff -Naur linux-4.9.8.org/net/netfilter/Kconfig linux-4.9.8/net/netfilter/Kconfig
--- linux-4.9.8.org/net/netfilter/Kconfig       2017-02-04 09:47:29.000000000 +0100
+++ linux-4.9.8/net/netfilter/Kconfig   2017-02-10 16:10:30.000000000 +0100
@@ -1238,6 +1238,26 @@
 
        To compile it as a module, choose M here. If unsure, say N.
 
+config NETFILTER_XT_MATCH_LAYER7
+       tristate '"layer7" match support'
+       depends on NETFILTER_XTABLES
+       depends on NETFILTER_ADVANCED
+       depends on NF_CONNTRACK
+       help
+         Say Y if you want to be able to classify connections (and their
+         packets) based on regular expression matching of their application
+         layer data.   This is one way to classify applications such as
+         peer-to-peer filesharing systems that do not always use the same
+         port.
+
+         To compile it as a module, choose M here.  If unsure, say N.
+
+config NETFILTER_XT_MATCH_LAYER7_DEBUG
+       bool 'Layer 7 debugging output'
+       depends on NETFILTER_XT_MATCH_LAYER7
+       help
+         Say Y to get lots of debugging output.
+
 config NETFILTER_XT_MATCH_LENGTH
        tristate '"length" match support'
        depends on NETFILTER_ADVANCED
diff -Naur linux-4.9.8.org/net/netfilter/Makefile linux-4.9.8/net/netfilter/Makefile
--- linux-4.9.8.org/net/netfilter/Makefile      2017-02-04 09:47:29.000000000 +0100
+++ linux-4.9.8/net/netfilter/Makefile  2017-02-10 16:10:30.000000000 +0100
@@ -174,6 +174,7 @@
 obj-$(CONFIG_NETFILTER_XT_MATCH_SCTP) += xt_sctp.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_SOCKET) += xt_socket.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_STATE) += xt_state.o
+obj-$(CONFIG_NETFILTER_XT_MATCH_LAYER7) += xt_layer7.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_STATISTIC) += xt_statistic.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_STRING) += xt_string.o
 obj-$(CONFIG_NETFILTER_XT_MATCH_TCPMSS) += xt_tcpmss.o
diff -Naur linux-4.9.8.org/net/netfilter/nf_conntrack_core.c linux-4.9.8/net/netfilter/nf_conntrack_core.c
--- linux-4.9.8.org/net/netfilter/nf_conntrack_core.c   2017-02-04 09:47:29.000000000 +0100
+++ linux-4.9.8/net/netfilter/nf_conntrack_core.c       2017-02-10 16:10:30.000000000 +0100
@@ -341,6 +341,13 @@
 {
        struct ct_pcpu *pcpu;
 
+#if defined(CONFIG_NETFILTER_XT_MATCH_LAYER7) || defined(CONFIG_NETFILTER_XT_MATCH_LAYER7_MODULE)
+       if(ct->layer7.app_proto)
+               kfree(ct->layer7.app_proto);
+       if(ct->layer7.app_data)
+               kfree(ct->layer7.app_data);
+#endif
+
        /* We overload first tuple to link into unconfirmed or dying list.*/
        pcpu = per_cpu_ptr(nf_ct_net(ct)->ct.pcpu_lists, ct->cpu);
 
diff -Naur linux-4.9.8.org/net/netfilter/nf_conntrack_standalone.c linux-4.9.8/net/netfilter/nf_conntrack_standalone.c
--- linux-4.9.8.org/net/netfilter/nf_conntrack_standalone.c     2017-02-04 09:47:29.000000000 +0100
+++ linux-4.9.8/net/netfilter/nf_conntrack_standalone.c 2017-02-10 16:10:30.000000000 +0100
@@ -274,6 +274,11 @@
        ct_show_zone(s, ct, NF_CT_DEFAULT_ZONE_DIR);
        ct_show_delta_time(s, ct);
 
+#if defined(CONFIG_NETFILTER_XT_MATCH_LAYER7) || defined(CONFIG_NETFILTER_XT_MATCH_LAYER7_MODULE)
+       if(ct->layer7.app_proto)
+               seq_printf(s, "l7proto=%s ", ct->layer7.app_proto);
+#endif
+
        seq_printf(s, "use=%u\n", atomic_read(&ct->ct_general.use));
 
        if (seq_has_overflowed(s))
diff -Naur linux-4.9.8.org/net/netfilter/regexp/regexp.c linux-4.9.8/net/netfilter/regexp/regexp.c
--- linux-4.9.8.org/net/netfilter/regexp/regexp.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-4.9.8/net/netfilter/regexp/regexp.c   2017-02-10 20:55:36.898611415 +0100
@@ -0,0 +1,1197 @@
+/*
+ * regcomp and regexec -- regsub and regerror are elsewhere
+ * @(#)regexp.c        1.3 of 18 April 87
+ *
+ *     Copyright (c) 1986 by University of Toronto.
+ *     Written by Henry Spencer.  Not derived from licensed software.
+ *
+ *     Permission is granted to anyone to use this software for any
+ *     purpose on any computer system, and to redistribute it freely,
+ *     subject to the following restrictions:
+ *
+ *     1. The author is not responsible for the consequences of use of
+ *             this software, no matter how awful, even if they arise
+ *             from defects in it.
+ *
+ *     2. The origin of this software must not be misrepresented, either
+ *             by explicit claim or by omission.
+ *
+ *     3. Altered versions must be plainly marked as such, and must not
+ *             be misrepresented as being the original software.
+ *
+ * Beware that some of this code is subtly aware of the way operator
+ * precedence is structured in regular expressions.  Serious changes in
+ * regular-expression syntax might require a total rethink.
+ *
+ * This code was modified by Ethan Sommer to work within the kernel
+ * (it now uses kmalloc etc..)
+ *
+ * Modified slightly by Matthew Strait to use more modern C.
+ */
+
+#include "regexp.h"
+#include "regmagic.h"
+
+/* added by ethan and matt.  Lets it work in both kernel and user space.
+(So iptables can use it, for instance.)  Yea, it goes both ways... */
+#if __KERNEL__
+  #define malloc(foo) kmalloc(foo,GFP_ATOMIC)
+#else
+  #define printk(format,args...) printf(format,##args)
+#endif
+
+void regerror(char * s)
+{
+        printk("<3>Regexp: %s\n", s);
+        /* NOTREACHED */
+}
+
+/*
+ * The "internal use only" fields in regexp.h are present to pass info from
+ * compile to execute that permits the execute phase to run lots faster on
+ * simple cases.  They are:
+ *
+ * regstart    char that must begin a match; '\0' if none obvious
+ * reganch     is the match anchored (at beginning-of-line only)?
+ * regmust     string (pointer into program) that match must include, or NULL
+ * regmlen     length of regmust string
+ *
+ * Regstart and reganch permit very fast decisions on suitable starting points
+ * for a match, cutting down the work a lot.  Regmust permits fast rejection
+ * of lines that cannot possibly match.  The regmust tests are costly enough
+ * that regcomp() supplies a regmust only if the r.e. contains something
+ * potentially expensive (at present, the only such thing detected is * or +
+ * at the start of the r.e., which can involve a lot of backup).  Regmlen is
+ * supplied because the test in regexec() needs it and regcomp() is computing
+ * it anyway.
+ */
+
+/*
+ * Structure for regexp "program".  This is essentially a linear encoding
+ * of a nondeterministic finite-state machine (aka syntax charts or
+ * "railroad normal form" in parsing technology).  Each node is an opcode
+ * plus a "next" pointer, possibly plus an operand.  "Next" pointers of
+ * all nodes except BRANCH implement concatenation; a "next" pointer with
+ * a BRANCH on both ends of it is connecting two alternatives.  (Here we
+ * have one of the subtle syntax dependencies:  an individual BRANCH (as
+ * opposed to a collection of them) is never concatenated with anything
+ * because of operator precedence.)  The operand of some types of node is
+ * a literal string; for others, it is a node leading into a sub-FSM.  In
+ * particular, the operand of a BRANCH node is the first node of the branch.
+ * (NB this is *not* a tree structure:  the tail of the branch connects
+ * to the thing following the set of BRANCHes.)  The opcodes are:
+ */
+
+/* definition  number  opnd?   meaning */
+#define        END     0       /* no   End of program. */
+#define        BOL     1       /* no   Match "" at beginning of line. */
+#define        EOL     2       /* no   Match "" at end of line. */
+#define        ANY     3       /* no   Match any one character. */
+#define        ANYOF   4       /* str  Match any character in this string. */
+#define        ANYBUT  5       /* str  Match any character not in this string. */
+#define        BRANCH  6       /* node Match this alternative, or the next... */
+#define        BACK    7       /* no   Match "", "next" ptr points backward. */
+#define        EXACTLY 8       /* str  Match this string. */
+#define        NOTHING 9       /* no   Match empty string. */
+#define        STAR    10      /* node Match this (simple) thing 0 or more times. */
+#define        PLUS    11      /* node Match this (simple) thing 1 or more times. */
+#define        OPEN    20      /* no   Mark this point in input as start of #n. */
+                       /*      OPEN+1 is number 1, etc. */
+#define        CLOSE   30      /* no   Analogous to OPEN. */
+
+/*
+ * Opcode notes:
+ *
+ * BRANCH      The set of branches constituting a single choice are hooked
+ *             together with their "next" pointers, since precedence prevents
+ *             anything being concatenated to any individual branch.  The
+ *             "next" pointer of the last BRANCH in a choice points to the
+ *             thing following the whole choice.  This is also where the
+ *             final "next" pointer of each individual branch points; each
+ *             branch starts with the operand node of a BRANCH node.
+ *
+ * BACK                Normal "next" pointers all implicitly point forward; BACK
+ *             exists to make loop structures possible.
+ *
+ * STAR,PLUS   '?', and complex '*' and '+', are implemented as circular
+ *             BRANCH structures using BACK.  Simple cases (one character
+ *             per match) are implemented with STAR and PLUS for speed
+ *             and to minimize recursive plunges.
+ *
+ * OPEN,CLOSE  ...are numbered at compile time.
+ */
+
+/*
+ * A node is one char of opcode followed by two chars of "next" pointer.
+ * "Next" pointers are stored as two 8-bit pieces, high order first.  The
+ * value is a positive offset from the opcode of the node containing it.
+ * An operand, if any, simply follows the node.  (Note that much of the
+ * code generation knows about this implicit relationship.)
+ *
+ * Using two bytes for the "next" pointer is vast overkill for most things,
+ * but allows patterns to get big without disasters.
+ */
+#define        OP(p)   (*(p))
+#define        NEXT(p) (((*((p)+1)&0377)<<8) + (*((p)+2)&0377))
+#define        OPERAND(p)      ((p) + 3)
+
+/*
+ * See regmagic.h for one further detail of program structure.
+ */
+
+
+/*
+ * Utility definitions.
+ */
+#ifndef CHARBITS
+#define        UCHARAT(p)      ((int)*(unsigned char *)(p))
+#else
+#define        UCHARAT(p)      ((int)*(p)&CHARBITS)
+#endif
+
+#define        FAIL(m) { regerror(m); return(NULL); }
+#define        ISMULT(c)       ((c) == '*' || (c) == '+' || (c) == '?')
+#define        META    "^$.[()|?+*\\"
+
+/*
+ * Flags to be passed up and down.
+ */
+#define        HASWIDTH        01      /* Known never to match null string. */
+#define        SIMPLE          02      /* Simple enough to be STAR/PLUS operand. */
+#define        SPSTART         04      /* Starts with * or +. */
+#define        WORST           0       /* Worst case. */
+
+/*
+ * Global work variables for regcomp().
+ */
+struct match_globals {
+char *reginput;                /* String-input pointer. */
+char *regbol;          /* Beginning of input, for ^ check. */
+char **regstartp;      /* Pointer to startp array. */
+char **regendp;                /* Ditto for endp. */
+char *regparse;                /* Input-scan pointer. */
+int regnpar;           /* () count. */
+char regdummy;
+char *regcode;         /* Code-emit pointer; &regdummy = don't. */
+long regsize;          /* Code size. */
+};
+
+/*
+ * Forward declarations for regcomp()'s friends.
+ */
+#ifndef STATIC
+#define        STATIC  static
+#endif
+STATIC char *reg(struct match_globals *g, int paren,int *flagp);
+STATIC char *regbranch(struct match_globals *g, int *flagp);
+STATIC char *regpiece(struct match_globals *g, int *flagp);
+STATIC char *regatom(struct match_globals *g, int *flagp);
+STATIC char *regnode(struct match_globals *g, char op);
+STATIC char *regnext(struct match_globals *g, char *p);
+STATIC void regc(struct match_globals *g, char b);
+STATIC void reginsert(struct match_globals *g, char op, char *opnd);
+STATIC void regtail(struct match_globals *g, char *p, char *val);
+STATIC void regoptail(struct match_globals *g, char *p, char *val);
+
+
+__kernel_size_t my_strcspn(const char *s1,const char *s2)
+{
+        char *scan1;
+        char *scan2;
+        int count;
+
+        count = 0;
+        for (scan1 = (char *)s1; *scan1 != '\0'; scan1++) {
+                for (scan2 = (char *)s2; *scan2 != '\0';)       /* ++ moved down. */
+                        if (*scan1 == *scan2++)
+                                return(count);
+                count++;
+        }
+        return(count);
+}
+
+/*
+ - regcomp - compile a regular expression into internal code
+ *
+ * We can't allocate space until we know how big the compiled form will be,
+ * but we can't compile it (and thus know how big it is) until we've got a
+ * place to put the code.  So we cheat:  we compile it twice, once with code
+ * generation turned off and size counting turned on, and once "for real".
+ * This also means that we don't allocate space until we are sure that the
+ * thing really will compile successfully, and we never have to move the
+ * code and thus invalidate pointers into it.  (Note that it has to be in
+ * one piece because free() must be able to free it all.)
+ *
+ * Beware that the optimization-preparation code in here knows about some
+ * of the structure of the compiled regexp.
+ */
+regexp *
+regcomp(char *exp,int *patternsize)
+{
+       register regexp *r;
+       register char *scan;
+       register char *longest;
+       register int len;
+       int flags;
+       struct match_globals g;
+       
+       /* commented out by ethan
+          extern char *malloc();
+       */
+
+       if (exp == NULL)
+               FAIL("NULL argument");
+
+       /* First pass: determine size, legality. */
+       g.regparse = exp;
+       g.regnpar = 1;
+       g.regsize = 0L;
+       g.regcode = &g.regdummy;
+       regc(&g, MAGIC);
+       if (reg(&g, 0, &flags) == NULL)
+               return(NULL);
+
+       /* Small enough for pointer-storage convention? */
+       if (g.regsize >= 32767L)                /* Probably could be 65535L. */
+               FAIL("regexp too big");
+
+       /* Allocate space. */
+       *patternsize=sizeof(regexp) + (unsigned)g.regsize;
+       r = (regexp *)malloc(sizeof(regexp) + (unsigned)g.regsize);
+       if (r == NULL)
+               FAIL("out of space");
+
+       /* Second pass: emit code. */
+       g.regparse = exp;
+       g.regnpar = 1;
+       g.regcode = r->program;
+       regc(&g, MAGIC);
+       if (reg(&g, 0, &flags) == NULL)
+               return(NULL);
+
+       /* Dig out information for optimizations. */
+       r->regstart = '\0';     /* Worst-case defaults. */
+       r->reganch = 0;
+       r->regmust = NULL;
+       r->regmlen = 0;
+       scan = r->program+1;                    /* First BRANCH. */
+       if (OP(regnext(&g, scan)) == END) {             /* Only one top-level choice. */
+               scan = OPERAND(scan);
+
+               /* Starting-point info. */
+               if (OP(scan) == EXACTLY)
+                       r->regstart = *OPERAND(scan);
+               else if (OP(scan) == BOL)
+                       r->reganch++;
+
+               /*
+                * If there's something expensive in the r.e., find the
+                * longest literal string that must appear and make it the
+                * regmust.  Resolve ties in favor of later strings, since
+                * the regstart check works with the beginning of the r.e.
+                * and avoiding duplication strengthens checking.  Not a
+                * strong reason, but sufficient in the absence of others.
+                */
+               if (flags&SPSTART) {
+                       longest = NULL;
+                       len = 0;
+                       for (; scan != NULL; scan = regnext(&g, scan))
+                               if (OP(scan) == EXACTLY && strlen(OPERAND(scan)) >= len) {
+                                       longest = OPERAND(scan);
+                                       len = strlen(OPERAND(scan));
+                               }
+                       r->regmust = longest;
+                       r->regmlen = len;
+               }
+       }
+
+       return(r);
+}
+
+/*
+ - reg - regular expression, i.e. main body or parenthesized thing
+ *
+ * Caller must absorb opening parenthesis.
+ *
+ * Combining parenthesis handling with the base level of regular expression
+ * is a trifle forced, but the need to tie the tails of the branches to what
+ * follows makes it hard to avoid.
+ */
+static char *
+reg(struct match_globals *g, int paren, int *flagp /* Parenthesized? */ )
+{
+       register char *ret;
+       register char *br;
+       register char *ender;
+       register int parno = 0; /* 0 makes gcc happy */
+       int flags;
+
+       *flagp = HASWIDTH;      /* Tentatively. */
+
+       /* Make an OPEN node, if parenthesized. */
+       if (paren) {
+               if (g->regnpar >= NSUBEXP)
+                       FAIL("too many ()");
+               parno = g->regnpar;
+               g->regnpar++;
+               ret = regnode(g, OPEN+parno);
+       } else
+               ret = NULL;
+
+       /* Pick up the branches, linking them together. */
+       br = regbranch(g, &flags);
+       if (br == NULL)
+               return(NULL);
+       if (ret != NULL)
+               regtail(g, ret, br);    /* OPEN -> first. */
+       else
+               ret = br;
+       if (!(flags&HASWIDTH))
+               *flagp &= ~HASWIDTH;
+       *flagp |= flags&SPSTART;
+       while (*g->regparse == '|') {
+               g->regparse++;
+               br = regbranch(g, &flags);
+               if (br == NULL)
+                       return(NULL);
+               regtail(g, ret, br);    /* BRANCH -> BRANCH. */
+               if (!(flags&HASWIDTH))
+                       *flagp &= ~HASWIDTH;
+               *flagp |= flags&SPSTART;
+       }
+
+       /* Make a closing node, and hook it on the end. */
+       ender = regnode(g, (paren) ? CLOSE+parno : END);        
+       regtail(g, ret, ender);
+
+       /* Hook the tails of the branches to the closing node. */
+       for (br = ret; br != NULL; br = regnext(g, br))
+               regoptail(g, br, ender);
+
+       /* Check for proper termination. */
+       if (paren && *g->regparse++ != ')') {
+               FAIL("unmatched ()");
+       } else if (!paren && *g->regparse != '\0') {
+               if (*g->regparse == ')') {
+                       FAIL("unmatched ()");
+               } else
+                       FAIL("junk on end");    /* "Can't happen". */
+               /* NOTREACHED */
+       }
+
+       return(ret);
+}
+
+/*
+ - regbranch - one alternative of an | operator
+ *
+ * Implements the concatenation operator.
+ */
+static char *
+regbranch(struct match_globals *g, int *flagp)
+{
+       register char *ret;
+       register char *chain;
+       register char *latest;
+       int flags;
+
+       *flagp = WORST;         /* Tentatively. */
+
+       ret = regnode(g, BRANCH);
+       chain = NULL;
+       while (*g->regparse != '\0' && *g->regparse != '|' && *g->regparse != ')') {
+               latest = regpiece(g, &flags);
+               if (latest == NULL)
+                       return(NULL);
+               *flagp |= flags&HASWIDTH;
+               if (chain == NULL)      /* First piece. */
+                       *flagp |= flags&SPSTART;
+               else
+                       regtail(g, chain, latest);
+               chain = latest;
+       }
+       if (chain == NULL)      /* Loop ran zero times. */
+               (void) regnode(g, NOTHING);
+
+       return(ret);
+}
+
+/*
+ - regpiece - something followed by possible [*+?]
+ *
+ * Note that the branching code sequences used for ? and the general cases
+ * of * and + are somewhat optimized:  they use the same NOTHING node as
+ * both the endmarker for their branch list and the body of the last branch.
+ * It might seem that this node could be dispensed with entirely, but the
+ * endmarker role is not redundant.
+ */
+static char *
+regpiece(struct match_globals *g, int *flagp)
+{
+       register char *ret;
+       register char op;
+       register char *next;
+       int flags;
+
+       ret = regatom(g, &flags);
+       if (ret == NULL)
+               return(NULL);
+
+       op = *g->regparse;
+       if (!ISMULT(op)) {
+               *flagp = flags;
+               return(ret);
+       }
+
+       if (!(flags&HASWIDTH) && op != '?')
+               FAIL("*+ operand could be empty");
+       *flagp = (op != '+') ? (WORST|SPSTART) : (WORST|HASWIDTH);
+
+       if (op == '*' && (flags&SIMPLE))
+               reginsert(g, STAR, ret);
+       else if (op == '*') {
+               /* Emit x* as (x&|), where & means "self". */
+               reginsert(g, BRANCH, ret);                      /* Either x */
+               regoptail(g, ret, regnode(g, BACK));            /* and loop */
+               regoptail(g, ret, ret);                 /* back */
+               regtail(g, ret, regnode(g, BRANCH));            /* or */
+               regtail(g, ret, regnode(g, NOTHING));           /* null. */
+       } else if (op == '+' && (flags&SIMPLE))
+               reginsert(g, PLUS, ret);
+       else if (op == '+') {
+               /* Emit x+ as x(&|), where & means "self". */
+               next = regnode(g, BRANCH);                      /* Either */
+               regtail(g, ret, next);
+               regtail(g, regnode(g, BACK), ret);              /* loop back */
+               regtail(g, next, regnode(g, BRANCH));           /* or */
+               regtail(g, ret, regnode(g, NOTHING));           /* null. */
+       } else if (op == '?') {
+               /* Emit x? as (x|) */
+               reginsert(g, BRANCH, ret);                      /* Either x */
+               regtail(g, ret, regnode(g, BRANCH));            /* or */
+               next = regnode(g, NOTHING);             /* null. */
+               regtail(g, ret, next);
+               regoptail(g, ret, next);
+       }
+       g->regparse++;
+       if (ISMULT(*g->regparse))
+               FAIL("nested *?+");
+
+       return(ret);
+}
+
+/*
+ - regatom - the lowest level
+ *
+ * Optimization:  gobbles an entire sequence of ordinary characters so that
+ * it can turn them into a single node, which is smaller to store and
+ * faster to run.  Backslashed characters are exceptions, each becoming a
+ * separate node; the code is simpler that way and it's not worth fixing.
+ */
+static char *
+regatom(struct match_globals *g, int *flagp)
+{
+       register char *ret;
+       int flags;
+
+       *flagp = WORST;         /* Tentatively. */
+
+       switch (*g->regparse++) {
+       case '^':
+               ret = regnode(g, BOL);
+               break;
+       case '$':
+               ret = regnode(g, EOL);
+               break;
+       case '.':
+               ret = regnode(g, ANY);
+               *flagp |= HASWIDTH|SIMPLE;
+               break;
+       case '[': {
+                       register int class;
+                       register int classend;
+
+                       if (*g->regparse == '^') {      /* Complement of range. */
+                               ret = regnode(g, ANYBUT);
+                               g->regparse++;
+                       } else
+                               ret = regnode(g, ANYOF);
+                       if (*g->regparse == ']' || *g->regparse == '-')
+                               regc(g, *g->regparse++);
+                       while (*g->regparse != '\0' && *g->regparse != ']') {
+                               if (*g->regparse == '-') {
+                                       g->regparse++;
+                                       if (*g->regparse == ']' || *g->regparse == '\0')
+                                               regc(g, '-');
+                                       else {
+                                               class = UCHARAT(g->regparse-2)+1;
+                                               classend = UCHARAT(g->regparse);
+                                               if (class > classend+1)
+                                                       FAIL("invalid [] range");
+                                               for (; class <= classend; class++)
+                                                       regc(g, class);
+                                               g->regparse++;
+                                       }
+                               } else
+                                       regc(g, *g->regparse++);
+                       }
+                       regc(g, '\0');
+                       if (*g->regparse != ']')
+                               FAIL("unmatched []");
+                       g->regparse++;
+                       *flagp |= HASWIDTH|SIMPLE;
+               }
+               break;
+       case '(':
+               ret = reg(g, 1, &flags);
+               if (ret == NULL)
+                       return(NULL);
+               *flagp |= flags&(HASWIDTH|SPSTART);
+               break;
+       case '\0':
+       case '|':
+       case ')':
+               FAIL("internal urp");   /* Supposed to be caught earlier. */
+               break;
+       case '?':
+       case '+':
+       case '*':
+               FAIL("?+* follows nothing");
+               break;
+       case '\\':
+               if (*g->regparse == '\0')
+                       FAIL("trailing \\");
+               ret = regnode(g, EXACTLY);
+               regc(g, *g->regparse++);
+               regc(g, '\0');
+               *flagp |= HASWIDTH|SIMPLE;
+               break;
+       default: {
+                       register int len;
+                       register char ender;
+
+                       g->regparse--;
+                       len = my_strcspn((const char *)g->regparse, (const char *)META);
+                       if (len <= 0)
+                               FAIL("internal disaster");
+                       ender = *(g->regparse+len);
+                       if (len > 1 && ISMULT(ender))
+                               len--;          /* Back off clear of ?+* operand. */
+                       *flagp |= HASWIDTH;
+                       if (len == 1)
+                               *flagp |= SIMPLE;
+                       ret = regnode(g, EXACTLY);
+                       while (len > 0) {
+                               regc(g, *g->regparse++);
+                               len--;
+                       }
+                       regc(g, '\0');
+               }
+               break;
+       }
+
+       return(ret);
+}
+
+/*
+ - regnode - emit a node
+ */
+static char *                  /* Location. */
+regnode(struct match_globals *g, char op)
+{
+       register char *ret;
+       register char *ptr;
+
+       ret = g->regcode;
+       if (ret == &g->regdummy) {
+               g->regsize += 3;
+               return(ret);
+       }
+
+       ptr = ret;
+       *ptr++ = op;
+       *ptr++ = '\0';          /* Null "next" pointer. */
+       *ptr++ = '\0';
+       g->regcode = ptr;
+
+       return(ret);
+}
+
+/*
+ - regc - emit (if appropriate) a byte of code
+ */
+static void
+regc(struct match_globals *g, char b)
+{
+       if (g->regcode != &g->regdummy)
+               *g->regcode++ = b;
+       else
+               g->regsize++;
+}
+
+/*
+ - reginsert - insert an operator in front of already-emitted operand
+ *
+ * Means relocating the operand.
+ */
+static void
+reginsert(struct match_globals *g, char op, char* opnd)
+{
+       register char *src;
+       register char *dst;
+       register char *place;
+
+       if (g->regcode == &g->regdummy) {
+               g->regsize += 3;
+               return;
+       }
+
+       src = g->regcode;
+       g->regcode += 3;
+       dst = g->regcode;
+       while (src > opnd)
+               *--dst = *--src;
+
+       place = opnd;           /* Op node, where operand used to be. */
+       *place++ = op;
+       *place++ = '\0';
+       *place++ = '\0';
+}
+
+/*
+ - regtail - set the next-pointer at the end of a node chain
+ */
+static void
+regtail(struct match_globals *g, char *p, char *val)
+{
+       register char *scan;
+       register char *temp;
+       register int offset;
+
+       if (p == &g->regdummy)
+               return;
+
+       /* Find last node. */
+       scan = p;
+       for (;;) {
+               temp = regnext(g, scan);
+               if (temp == NULL)
+                       break;
+               scan = temp;
+       }
+
+       if (OP(scan) == BACK)
+               offset = scan - val;
+       else
+               offset = val - scan;
+       *(scan+1) = (offset>>8)&0377;
+       *(scan+2) = offset&0377;
+}
+
+/*
+ - regoptail - regtail on operand of first argument; nop if operandless
+ */
+static void
+regoptail(struct match_globals *g, char *p, char *val)
+{
+       /* "Operandless" and "op != BRANCH" are synonymous in practice. */
+       if (p == NULL || p == &g->regdummy || OP(p) != BRANCH)
+               return;
+       regtail(g, OPERAND(p), val);
+}
+
+/*
+ * regexec and friends
+ */
+
+
+/*
+ * Forwards.
+ */
+STATIC int regtry(struct match_globals *g, regexp *prog, char *string);
+STATIC int regmatch(struct match_globals *g, char *prog);
+STATIC int regrepeat(struct match_globals *g, char *p);
+
+#ifdef DEBUG
+int regnarrate = 0;
+void regdump();
+STATIC char *regprop(char *op);
+#endif
+
+/*
+ - regexec - match a regexp against a string
+ */
+int
+regexec(regexp *prog, char *string)
+{
+       register char *s;
+       struct match_globals g;
+
+       /* Be paranoid... */
+       if (prog == NULL || string == NULL) {
+               printk("<3>Regexp: NULL parameter\n");
+               return(0);
+       }
+
+       /* Check validity of program. */
+       if (UCHARAT(prog->program) != MAGIC) {
+               printk("<3>Regexp: corrupted program\n");
+               return(0);
+       }
+
+       /* If there is a "must appear" string, look for it. */
+       if (prog->regmust != NULL) {
+               s = string;
+               while ((s = strchr(s, prog->regmust[0])) != NULL) {
+                       if (strncmp(s, prog->regmust, prog->regmlen) == 0)
+                               break;  /* Found it. */
+                       s++;
+               }
+               if (s == NULL)  /* Not present. */
+                       return(0);
+       }
+
+       /* Mark beginning of line for ^ . */
+       g.regbol = string;
+
+       /* Simplest case:  anchored match need be tried only once. */
+       if (prog->reganch)
+               return(regtry(&g, prog, string));
+
+       /* Messy cases:  unanchored match. */
+       s = string;
+       if (prog->regstart != '\0')
+               /* We know what char it must start with. */
+               while ((s = strchr(s, prog->regstart)) != NULL) {
+                       if (regtry(&g, prog, s))
+                               return(1);
+                       s++;
+               }
+       else
+               /* We don't -- general case. */
+               do {
+                       if (regtry(&g, prog, s))
+                               return(1);
+               } while (*s++ != '\0');
+
+       /* Failure. */
+       return(0);
+}
+
+/*
+ - regtry - try match at specific point
+ */
+static int                     /* 0 failure, 1 success */
+regtry(struct match_globals *g, regexp *prog, char *string)
+{
+       register int i;
+       register char **sp;
+       register char **ep;
+
+       g->reginput = string;
+       g->regstartp = prog->startp;
+       g->regendp = prog->endp;
+
+       sp = prog->startp;
+       ep = prog->endp;
+       for (i = NSUBEXP; i > 0; i--) {
+               *sp++ = NULL;
+               *ep++ = NULL;
+       }
+       if (regmatch(g, prog->program + 1)) {
+               prog->startp[0] = string;
+               prog->endp[0] = g->reginput;
+               return(1);
+       } else
+               return(0);
+}
+
+/*
+ - regmatch - main matching routine
+ *
+ * Conceptually the strategy is simple:  check to see whether the current
+ * node matches, call self recursively to see whether the rest matches,
+ * and then act accordingly.  In practice we make some effort to avoid
+ * recursion, in particular by going through "ordinary" nodes (that don't
+ * need to know whether the rest of the match failed) by a loop instead of
+ * by recursion.
+ */
+static int                     /* 0 failure, 1 success */
+regmatch(struct match_globals *g, char *prog)
+{
+       register char *scan = prog; /* Current node. */
+       char *next;                 /* Next node. */
+
+#ifdef DEBUG
+       if (scan != NULL && regnarrate)
+               fprintf(stderr, "%s(\n", regprop(scan));
+#endif
+       while (scan != NULL) {
+#ifdef DEBUG
+               if (regnarrate)
+                       fprintf(stderr, "%s...\n", regprop(scan));
+#endif
+               next = regnext(g, scan);
+
+               switch (OP(scan)) {
+               case BOL:
+                       if (g->reginput != g->regbol)
+                               return(0);
+                       break;
+               case EOL:
+                       if (*g->reginput != '\0')
+                               return(0);
+                       break;
+               case ANY:
+                       if (*g->reginput == '\0')
+                               return(0);
+                       g->reginput++;
+                       break;
+               case EXACTLY: {
+                               register int len;
+                               register char *opnd;
+
+                               opnd = OPERAND(scan);
+                               /* Inline the first character, for speed. */
+                               if (*opnd != *g->reginput)
+                                       return(0);
+                               len = strlen(opnd);
+                               if (len > 1 && strncmp(opnd, g->reginput, len) != 0)
+                                       return(0);
+                               g->reginput += len;
+                       }
+                       break;
+               case ANYOF:
+                       if (*g->reginput == '\0' || strchr(OPERAND(scan), *g->reginput) == NULL)
+                               return(0);
+                       g->reginput++;
+                       break;
+               case ANYBUT:
+                       if (*g->reginput == '\0' || strchr(OPERAND(scan), *g->reginput) != NULL)
+                               return(0);
+                       g->reginput++;
+                       break;
+               case NOTHING:
+               case BACK:
+                       break;
+               case OPEN+1:
+               case OPEN+2:
+               case OPEN+3:
+               case OPEN+4:
+               case OPEN+5:
+               case OPEN+6:
+               case OPEN+7:
+               case OPEN+8:
+               case OPEN+9: {
+                               register int no;
+                               register char *save;
+
+                               no = OP(scan) - OPEN;
+                               save = g->reginput;
+
+                               if (regmatch(g, next)) {
+                                       /*
+                                        * Don't set startp if some later
+                                        * invocation of the same parentheses
+                                        * already has.
+                                        */
+                                       if (g->regstartp[no] == NULL)
+                                               g->regstartp[no] = save;
+                                       return(1);
+                               } else
+                                       return(0);
+                       }
+                       break;
+               case CLOSE+1:
+               case CLOSE+2:
+               case CLOSE+3:
+               case CLOSE+4:
+               case CLOSE+5:
+               case CLOSE+6:
+               case CLOSE+7:
+               case CLOSE+8:
+               case CLOSE+9:
+                       {
+                               register int no;
+                               register char *save;
+
+                               no = OP(scan) - CLOSE;
+                               save = g->reginput;
+
+                               if (regmatch(g, next)) {
+                                       /*
+                                        * Don't set endp if some later
+                                        * invocation of the same parentheses
+                                        * already has.
+                                        */
+                                       if (g->regendp[no] == NULL)
+                                               g->regendp[no] = save;
+                                       return(1);
+                               } else
+                                       return(0);
+                       }
+                       break;
+               case BRANCH: {
+                               register char *save;
+
+                               if (OP(next) != BRANCH)         /* No choice. */
+                                       next = OPERAND(scan);   /* Avoid recursion. */
+                               else {
+                                       do {
+                                               save = g->reginput;
+                                               if (regmatch(g, OPERAND(scan)))
+                                                       return(1);
+                                               g->reginput = save;
+                                               scan = regnext(g, scan);
+                                       } while (scan != NULL && OP(scan) == BRANCH);
+                                       return(0);
+                                       /* NOTREACHED */
+                               }
+                       }
+                       break;
+               case STAR:
+               case PLUS: {
+                               register char nextch;
+                               register int no;
+                               register char *save;
+                               register int min;
+
+                               /*
+                                * Lookahead to avoid useless match attempts
+                                * when we know what character comes next.
+                                */
+                               nextch = '\0';
+                               if (OP(next) == EXACTLY)
+                                       nextch = *OPERAND(next);
+                               min = (OP(scan) == STAR) ? 0 : 1;
+                               save = g->reginput;
+                               no = regrepeat(g, OPERAND(scan));
+                               while (no >= min) {
+                                       /* If it could work, try it. */
+                                       if (nextch == '\0' || *g->reginput == nextch)
+                                               if (regmatch(g, next))
+                                                       return(1);
+                                       /* Couldn't or didn't -- back up. */
+                                       no--;
+                                       g->reginput = save + no;
+                               }
+                               return(0);
+                       }
+                       break;
+               case END:
+                       return(1);      /* Success! */
+                       break;
+               default:
+                       printk("<3>Regexp: memory corruption\n");
+                       return(0);
+                       break;
+               }
+
+               scan = next;
+       }
+
+       /*
+        * We get here only if there's trouble -- normally "case END" is
+        * the terminating point.
+        */
+       printk("<3>Regexp: corrupted pointers\n");
+       return(0);
+}
+
+/*
+ - regrepeat - repeatedly match something simple, report how many
+ */
+static int
+regrepeat(struct match_globals *g, char *p)
+{
+       register int count = 0;
+       register char *scan;
+       register char *opnd;
+
+       scan = g->reginput;
+       opnd = OPERAND(p);
+       switch (OP(p)) {
+       case ANY:
+               count = strlen(scan);
+               scan += count;
+               break;
+       case EXACTLY:
+               while (*opnd == *scan) {
+                       count++;
+                       scan++;
+               }
+               break;
+       case ANYOF:
+               while (*scan != '\0' && strchr(opnd, *scan) != NULL) {
+                       count++;
+                       scan++;
+               }
+               break;
+       case ANYBUT:
+               while (*scan != '\0' && strchr(opnd, *scan) == NULL) {
+                       count++;
+                       scan++;
+               }
+               break;
+       default:                /* Oh dear.  Called inappropriately. */
+               printk("<3>Regexp: internal foulup\n");
+               count = 0;      /* Best compromise. */
+               break;
+       }
+       g->reginput = scan;
+
+       return(count);
+}
+
+/*
+ - regnext - dig the "next" pointer out of a node
+ */
+static char*
+regnext(struct match_globals *g, char *p)
+{
+       register int offset;
+
+       if (p == &g->regdummy)
+               return(NULL);
+
+       offset = NEXT(p);
+       if (offset == 0)
+               return(NULL);
+
+       if (OP(p) == BACK)
+               return(p-offset);
+       else
+               return(p+offset);
+}
+
+#ifdef DEBUG
+
+STATIC char *regprop();
+
+/*
+ - regdump - dump a regexp onto stdout in vaguely comprehensible form
+ */
+void
+regdump(regexp *r)
+{
+       register char *s;
+       register char op = EXACTLY;     /* Arbitrary non-END op. */
+       register char *next;
+       /* extern char *strchr(); */
+
+
+       s = r->program + 1;
+       while (op != END) {     /* While that wasn't END last time... */
+               op = OP(s);
+               printf("%2d%s", s-r->program, regprop(s));      /* Where, what. */
+               next = regnext(s);
+               if (next == NULL)               /* Next ptr. */
+                       printf("(0)");
+               else
+                       printf("(%d)", (s-r->program)+(next-s));
+               s += 3;
+               if (op == ANYOF || op == ANYBUT || op == EXACTLY) {
+                       /* Literal string, where present. */
+                       while (*s != '\0') {
+                               putchar(*s);
+                               s++;
+                       }
+                       s++;
+               }
+               putchar('\n');
+       }
+
+       /* Header fields of interest. */
+       if (r->regstart != '\0')
+               printf("start `%c' ", r->regstart);
+       if (r->reganch)
+               printf("anchored ");
+       if (r->regmust != NULL)
+               printf("must have \"%s\"", r->regmust);
+       printf("\n");
+}
+
+/*
+ - regprop - printable representation of opcode
+ */
+static char *
+regprop(char *op)
+{
+#define BUFLEN 50
+       register char *p;
+       static char buf[BUFLEN];
+
+       strcpy(buf, ":");
+
+       switch (OP(op)) {
+       case BOL:
+               p = "BOL";
+               break;
+       case EOL:
+               p = "EOL";
+               break;
+       case ANY:
+               p = "ANY";
+               break;
+       case ANYOF:
+               p = "ANYOF";
+               break;
+       case ANYBUT:
+               p = "ANYBUT";
+               break;
+       case BRANCH:
+               p = "BRANCH";
+               break;
+       case EXACTLY:
+               p = "EXACTLY";
+               break;
+       case NOTHING:
+               p = "NOTHING";
+               break;
+       case BACK:
+               p = "BACK";
+               break;
+       case END:
+               p = "END";
+               break;
+       case OPEN+1:
+       case OPEN+2:
+       case OPEN+3:
+       case OPEN+4:
+       case OPEN+5:
+       case OPEN+6:
+       case OPEN+7:
+       case OPEN+8:
+       case OPEN+9:
+               snprintf(buf+strlen(buf),BUFLEN-strlen(buf), "OPEN%d", OP(op)-OPEN);
+               p = NULL;
+               break;
+       case CLOSE+1:
+       case CLOSE+2:
+       case CLOSE+3:
+       case CLOSE+4:
+       case CLOSE+5:
+       case CLOSE+6:
+       case CLOSE+7:
+       case CLOSE+8:
+       case CLOSE+9:
+               snprintf(buf+strlen(buf),BUFLEN-strlen(buf), "CLOSE%d", OP(op)-CLOSE);
+               p = NULL;
+               break;
+       case STAR:
+               p = "STAR";
+               break;
+       case PLUS:
+               p = "PLUS";
+               break;
+       default:
+               printk("<3>Regexp: corrupted opcode\n");
+               break;
+       }
+       if (p != NULL)
+               strncat(buf, p, BUFLEN-strlen(buf));
+       return(buf);
+}
+#endif
+
+
diff -Naur linux-4.9.8.org/net/netfilter/regexp/regexp.h linux-4.9.8/net/netfilter/regexp/regexp.h
--- linux-4.9.8.org/net/netfilter/regexp/regexp.h       1970-01-01 01:00:00.000000000 +0100
+++ linux-4.9.8/net/netfilter/regexp/regexp.h   2017-02-10 20:55:36.898611415 +0100
@@ -0,0 +1,41 @@
+/*
+ * Definitions etc. for regexp(3) routines.
+ *
+ * Caveat:  this is V8 regexp(3) [actually, a reimplementation thereof],
+ * not the System V one.
+ */
+
+#ifndef REGEXP_H
+#define REGEXP_H
+
+
+/*
+http://www.opensource.apple.com/darwinsource/10.3/expect-1/expect/expect.h ,
+which contains a version of this library, says:
+
+ *
+ * NSUBEXP must be at least 10, and no greater than 117 or the parser
+ * will not work properly.
+ *
+
+However, it looks rather like this library is limited to 10.  If you think
+otherwise, let us know.
+*/
+
+#define NSUBEXP  10
+typedef struct regexp {
+       char *startp[NSUBEXP];
+       char *endp[NSUBEXP];
+       char regstart;          /* Internal use only. */
+       char reganch;           /* Internal use only. */
+       char *regmust;          /* Internal use only. */
+       int regmlen;            /* Internal use only. */
+       char program[1];        /* Unwarranted chumminess with compiler. */
+} regexp;
+
+regexp * regcomp(char *exp, int *patternsize);
+int regexec(regexp *prog, char *string);
+void regsub(regexp *prog, char *source, char *dest);
+void regerror(char *s);
+
+#endif
diff -Naur linux-4.9.8.org/net/netfilter/regexp/regmagic.h linux-4.9.8/net/netfilter/regexp/regmagic.h
--- linux-4.9.8.org/net/netfilter/regexp/regmagic.h     1970-01-01 01:00:00.000000000 +0100
+++ linux-4.9.8/net/netfilter/regexp/regmagic.h 2017-02-10 20:55:36.898611415 +0100
@@ -0,0 +1,5 @@
+/*
+ * The first byte of the regexp internal "program" is actually this magic
+ * number; the start node begins in the second byte.
+ */
+#define        MAGIC   0234
diff -Naur linux-4.9.8.org/net/netfilter/regexp/regsub.c linux-4.9.8/net/netfilter/regexp/regsub.c
--- linux-4.9.8.org/net/netfilter/regexp/regsub.c       1970-01-01 01:00:00.000000000 +0100
+++ linux-4.9.8/net/netfilter/regexp/regsub.c   2017-02-10 20:55:36.898611415 +0100
@@ -0,0 +1,95 @@
+/*
+ * regsub
+ * @(#)regsub.c        1.3 of 2 April 86
+ *
+ *     Copyright (c) 1986 by University of Toronto.
+ *     Written by Henry Spencer.  Not derived from licensed software.
+ *
+ *     Permission is granted to anyone to use this software for any
+ *     purpose on any computer system, and to redistribute it freely,
+ *     subject to the following restrictions:
+ *
+ *     1. The author is not responsible for the consequences of use of
+ *             this software, no matter how awful, even if they arise
+ *             from defects in it.
+ *
+ *     2. The origin of this software must not be misrepresented, either
+ *             by explicit claim or by omission.
+ *
+ *     3. Altered versions must be plainly marked as such, and must not
+ *             be misrepresented as being the original software.
+ *
+ *
+ * This code was modified by Ethan Sommer to work within the kernel
+ * (it now uses kmalloc etc..)
+ *
+ */
+#include "regexp.h"
+#include "regmagic.h"
+#include <linux/string.h>
+
+
+#ifndef CHARBITS
+#define        UCHARAT(p)      ((int)*(unsigned char *)(p))
+#else
+#define        UCHARAT(p)      ((int)*(p)&CHARBITS)
+#endif
+
+#if 0
+//void regerror(char * s)
+//{
+//        printk("regexp(3): %s", s);
+//        /* NOTREACHED */
+//}
+#endif
+
+/*
+ - regsub - perform substitutions after a regexp match
+ */
+void
+regsub(regexp * prog, char * source, char * dest)
+{
+       register char *src;
+       register char *dst;
+       register char c;
+       register int no;
+       register int len;
+       
+       /* Not necessary and gcc doesn't like it -MLS */
+       /*extern char *strncpy();*/
+
+       if (prog == NULL || source == NULL || dest == NULL) {
+               regerror("NULL parm to regsub");
+               return;
+       }
+       if (UCHARAT(prog->program) != MAGIC) {
+               regerror("damaged regexp fed to regsub");
+               return;
+       }
+
+       src = source;
+       dst = dest;
+       while ((c = *src++) != '\0') {
+               if (c == '&')
+                       no = 0;
+               else if (c == '\\' && '0' <= *src && *src <= '9')
+                       no = *src++ - '0';
+               else
+                       no = -1;
+
+               if (no < 0) {   /* Ordinary character. */
+                       if (c == '\\' && (*src == '\\' || *src == '&'))
+                               c = *src++;
+                       *dst++ = c;
+               } else if (prog->startp[no] != NULL && prog->endp[no] != NULL) {
+                       len = prog->endp[no] - prog->startp[no];
+                       (void) strncpy(dst, prog->startp[no], len);
+                       dst += len;
+                       if (len != 0 && *(dst-1) == '\0') {     /* strncpy hit NUL. */
+                               regerror("damaged match string");
+                               return;
+                       }
+               }
+       }
+       *dst++ = '\0';
+}
diff -Naur linux-4.9.8.org/net/netfilter/xt_layer7.c linux-4.9.8/net/netfilter/xt_layer7.c
--- linux-4.9.8.org/net/netfilter/xt_layer7.c   1970-01-01 01:00:00.000000000 +0100
+++ linux-4.9.8/net/netfilter/xt_layer7.c       2017-02-10 22:42:57.750923134 +0100
@@ -0,0 +1,658 @@
+/*
+  Kernel module to match application layer (OSI layer 7) data in connections.
+
+  http://l7-filter.sf.net
+
+  (C) 2003-2009 Matthew Strait and Ethan Sommer.
+
+  This program is free software; you can redistribute it and/or
+  modify it under the terms of the GNU General Public License
+  as published by the Free Software Foundation; either version
+  2 of the License, or (at your option) any later version.
+  http://www.gnu.org/licenses/gpl.txt
+
+  Based on ipt_string.c (C) 2000 Emmanuel Roger <winfield@freegates.be>,
+  xt_helper.c (C) 2002 Harald Welte and cls_layer7.c (C) 2003 Matthew Strait,
+  Ethan Sommer, Justin Levandoski.
+*/
+
+#include <linux/spinlock.h>
+#include <linux/version.h>
+#include <net/ip.h>
+#include <net/tcp.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/netfilter.h>
+#include <net/netfilter/nf_conntrack.h>
+#include <net/netfilter/nf_conntrack_core.h>
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 27)
+#include <net/netfilter/nf_conntrack_extend.h>
+#include <net/netfilter/nf_conntrack_acct.h>
+#endif
+#include <linux/netfilter/x_tables.h>
+#include <linux/netfilter/xt_layer7.h>
+#include <linux/ctype.h>
+#include <linux/proc_fs.h>
+
+#include "regexp/regexp.c"
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Matthew Strait <quadong@users.sf.net>, Ethan Sommer <sommere@users.sf.net>");
+MODULE_DESCRIPTION("iptables application layer match module");
+MODULE_ALIAS("ipt_layer7");
+MODULE_VERSION("2.23");
+
+static int maxdatalen = 2048; // this is the default
+module_param(maxdatalen, int, 0444);
+MODULE_PARM_DESC(maxdatalen, "maximum bytes of data looked at by l7-filter");
+#ifdef CONFIG_NETFILTER_XT_MATCH_LAYER7_DEBUG
+       #define DPRINTK(format,args...) printk(format,##args)
+#else
+       #define DPRINTK(format,args...)
+#endif
+
+/* Number of packets whose data we look at.
+This can be modified through /proc/net/layer7_numpackets */
+static int num_packets = 10;
+
+static struct pattern_cache {
+       char * regex_string;
+       regexp * pattern;
+       struct pattern_cache * next;
+} * first_pattern_cache = NULL;
+
+DEFINE_SPINLOCK(l7_lock);
+
+static int total_acct_packets(struct nf_conn *ct)
+{
+#if LINUX_VERSION_CODE <= KERNEL_VERSION(2, 6, 26)
+       BUG_ON(ct == NULL);
+       return (ct->counters[IP_CT_DIR_ORIGINAL].packets + ct->counters[IP_CT_DIR_REPLY].packets);
+#else
+       struct nf_conn_counter *acct;
+
+       BUG_ON(ct == NULL);
+       acct = nf_conn_acct_find(ct);
+       if (!acct)
+               return 0;
+        return (atomic64_read(&acct[IP_CT_DIR_ORIGINAL].packets) + atomic64_read(&acct[IP_CT_DIR_REPLY].packets));
+#endif
+}
+
+#ifdef CONFIG_IP_NF_MATCH_LAYER7_DEBUG
+/* Converts an unfriendly string into a friendly one by
+replacing unprintables with periods and all whitespace with " ". */
+static char * friendly_print(unsigned char * s)
+{
+       char * f = kmalloc(strlen(s) + 1, GFP_ATOMIC);
+       int i;
+
+       if(!f) {
+               if (net_ratelimit())
+                       printk(KERN_ERR "layer7: out of memory in "
+                                       "friendly_print, bailing.\n");
+               return NULL;
+       }
+
+       for(i = 0; i < strlen(s); i++){
+               if(isprint(s[i]) && s[i] < 128) f[i] = s[i];
+               else if(isspace(s[i]))          f[i] = ' ';
+               else                            f[i] = '.';
+       }
+       f[i] = '\0';
+       return f;
+}
+
+static char dec2hex(int i)
+{
+       switch (i) {
+               case 0 ... 9:
+                       return (i + '0');
+                       break;
+               case 10 ... 15:
+                       return (i - 10 + 'a');
+                       break;
+               default:
+                       if (net_ratelimit())
+                               printk("layer7: Problem in dec2hex\n");
+                       return '\0';
+       }
+}
+
+static char * hex_print(unsigned char * s)
+{
+       char * g = kmalloc(strlen(s)*3 + 1, GFP_ATOMIC);
+       int i;
+
+       if(!g) {
+              if (net_ratelimit())
+                       printk(KERN_ERR "layer7: out of memory in hex_print, "
+                                       "bailing.\n");
+              return NULL;
+       }
+
+       for(i = 0; i < strlen(s); i++) {
+               g[i*3    ] = dec2hex(s[i]/16);
+               g[i*3 + 1] = dec2hex(s[i]%16);
+               g[i*3 + 2] = ' ';
+       }
+       g[i*3] = '\0';
+
+       return g;
+}
+#endif // DEBUG
+
+/* Use instead of regcomp.  As we expect to be seeing the same regexps over and
+over again, it make sense to cache the results. */
+static regexp * compile_and_cache(const char * regex_string, 
+                                  const char * protocol)
+{
+       struct pattern_cache * node               = first_pattern_cache;
+       struct pattern_cache * last_pattern_cache = first_pattern_cache;
+       struct pattern_cache * tmp;
+       unsigned int len;
+
+       while (node != NULL) {
+               if (!strcmp(node->regex_string, regex_string))
+               return node->pattern;
+
+               last_pattern_cache = node;/* points at the last non-NULL node */
+               node = node->next;
+       }
+
+       /* If we reach the end of the list, then we have not yet cached
+          the pattern for this regex. Let's do that now.
+          Be paranoid about running out of memory to avoid list corruption. */
+       tmp = kmalloc(sizeof(struct pattern_cache), GFP_ATOMIC);
+
+       if(!tmp) {
+               if (net_ratelimit())
+                       printk(KERN_ERR "layer7: out of memory in "
+                                       "compile_and_cache, bailing.\n");
+               return NULL;
+       }
+
+       tmp->regex_string  = kmalloc(strlen(regex_string) + 1, GFP_ATOMIC);
+       tmp->pattern       = kmalloc(sizeof(struct regexp),    GFP_ATOMIC);
+       tmp->next = NULL;
+
+       if(!tmp->regex_string || !tmp->pattern) {
+               if (net_ratelimit())
+                       printk(KERN_ERR "layer7: out of memory in "
+                                       "compile_and_cache, bailing.\n");
+               kfree(tmp->regex_string);
+               kfree(tmp->pattern);
+               kfree(tmp);
+               return NULL;
+       }
+
+       /* Ok.  The new node is all ready now. */
+       node = tmp;
+
+       if(first_pattern_cache == NULL) /* list is empty */
+               first_pattern_cache = node; /* make node the beginning */
+       else
+               last_pattern_cache->next = node; /* attach node to the end */
+
+       /* copy the string and compile the regex */
+       len = strlen(regex_string);
+       DPRINTK("About to compile this: \"%s\"\n", regex_string);
+       node->pattern = regcomp((char *)regex_string, &len);
+       if ( !node->pattern ) {
+               if (net_ratelimit())
+                       printk(KERN_ERR "layer7: Error compiling regexp "
+                                       "\"%s\" (%s)\n", 
+                                       regex_string, protocol);
+               /* pattern is now cached as NULL, so we won't try again. */
+       }
+
+       strcpy(node->regex_string, regex_string);
+       return node->pattern;
+}
+
+static int can_handle(const struct sk_buff *skb)
+{
+       if(!ip_hdr(skb)) /* not IP */
+               return 0;
+       if(ip_hdr(skb)->protocol != IPPROTO_TCP &&
+          ip_hdr(skb)->protocol != IPPROTO_UDP &&
+          ip_hdr(skb)->protocol != IPPROTO_ICMP)
+               return 0;
+       return 1;
+}
+
+/* Returns offset the into the skb->data that the application data starts */
+static int app_data_offset(const struct sk_buff *skb)
+{
+       /* In case we are ported somewhere (ebtables?) where ip_hdr(skb)
+       isn't set, this can be gotten from 4*(skb->data[0] & 0x0f) as well. */
+       int ip_hl = 4*ip_hdr(skb)->ihl;
+
+       if( ip_hdr(skb)->protocol == IPPROTO_TCP ) {
+               /* 12 == offset into TCP header for the header length field.
+               Can't get this with skb->h.th->doff because the tcphdr
+               struct doesn't get set when routing (this is confirmed to be
+               true in Netfilter as well as QoS.) */
+               int tcp_hl = 4*(skb->data[ip_hl + 12] >> 4);
+
+               return ip_hl + tcp_hl;
+       } else if( ip_hdr(skb)->protocol == IPPROTO_UDP  ) {
+               return ip_hl + 8; /* UDP header is always 8 bytes */
+       } else if( ip_hdr(skb)->protocol == IPPROTO_ICMP ) {
+               return ip_hl + 8; /* ICMP header is 8 bytes */
+       } else {
+               if (net_ratelimit())
+                       printk(KERN_ERR "layer7: tried to handle unknown "
+                                       "protocol!\n");
+               return ip_hl + 8; /* something reasonable */
+       }
+}
+
+/* handles whether there's a match when we aren't appending data anymore */
+static int match_no_append(struct nf_conn * conntrack, 
+                           struct nf_conn * master_conntrack, 
+                           enum ip_conntrack_info ctinfo,
+                           enum ip_conntrack_info master_ctinfo,
+                           const struct xt_layer7_info * info)
+{
+       /* If we're in here, throw the app data away */
+       if(master_conntrack->layer7.app_data != NULL) {
+
+       #ifdef CONFIG_IP_NF_MATCH_LAYER7_DEBUG
+               if(!master_conntrack->layer7.app_proto) {
+                       char * f = 
+                         friendly_print(master_conntrack->layer7.app_data);
+                       char * g = 
+                         hex_print(master_conntrack->layer7.app_data);
+                       DPRINTK("\nl7-filter gave up after %d bytes "
+                               "(%d packets):\n%s\n",
+                               strlen(f), total_acct_packets(master_conntrack), f);
+                       kfree(f);
+                       DPRINTK("In hex: %s\n", g);
+                       kfree(g);
+               }
+       #endif
+
+               kfree(master_conntrack->layer7.app_data);
+               master_conntrack->layer7.app_data = NULL; /* don't free again */
+       }
+
+       if(master_conntrack->layer7.app_proto){
+               /* Here child connections set their .app_proto (for /proc) */
+               if(!conntrack->layer7.app_proto) {
+                       conntrack->layer7.app_proto = 
+                         kmalloc(strlen(master_conntrack->layer7.app_proto)+1, 
+                           GFP_ATOMIC);
+                       if(!conntrack->layer7.app_proto){
+                               if (net_ratelimit())
+                                       printk(KERN_ERR "layer7: out of memory "
+                                                       "in match_no_append, "
+                                                       "bailing.\n");
+                               return 1;
+                       }
+                       strcpy(conntrack->layer7.app_proto, 
+                               master_conntrack->layer7.app_proto);
+               }
+
+               return (!strcmp(master_conntrack->layer7.app_proto, 
+                               info->protocol));
+       }
+       else {
+               /* If not classified, set to "unknown" to distinguish from
+               connections that are still being tested. */
+               master_conntrack->layer7.app_proto = 
+                       kmalloc(strlen("unknown")+1, GFP_ATOMIC);
+               if(!master_conntrack->layer7.app_proto){
+                       if (net_ratelimit())
+                               printk(KERN_ERR "layer7: out of memory in "
+                                               "match_no_append, bailing.\n");
+                       return 1;
+               }
+               strcpy(master_conntrack->layer7.app_proto, "unknown");
+               return 0;
+       }
+}
+
+/* add the new app data to the conntrack.  Return number of bytes added. */
+static int add_data(struct nf_conn * master_conntrack,
+                    char * app_data, int appdatalen)
+{
+       int length = 0, i;
+       int oldlength = master_conntrack->layer7.app_data_len;
+
+       /* This is a fix for a race condition by Deti Fliegl. However, I'm not 
+          clear on whether the race condition exists or whether this really 
+          fixes it.  I might just be being dense... Anyway, if it's not really 
+          a fix, all it does is waste a very small amount of time. */
+       if(!master_conntrack->layer7.app_data) return 0;
+
+       /* Strip nulls. Make everything lower case (our regex lib doesn't
+       do case insensitivity).  Add it to the end of the current data. */
+       for(i = 0; i < maxdatalen-oldlength-1 &&
+                  i < appdatalen; i++) {
+               if(app_data[i] != '\0') {
+                       /* the kernel version of tolower mungs 'upper ascii' */
+                       master_conntrack->layer7.app_data[length+oldlength] =
+                               isascii(app_data[i])? 
+                                       tolower(app_data[i]) : app_data[i];
+                       length++;
+               }
+       }
+
+       master_conntrack->layer7.app_data[length+oldlength] = '\0';
+       master_conntrack->layer7.app_data_len = length + oldlength;
+
+       return length;
+}
+
+/* taken from drivers/video/modedb.c */
+static int my_atoi(const char *s)
+{
+       int val = 0;
+
+       for (;; s++) {
+               switch (*s) {
+                       case '0'...'9':
+                       val = 10*val+(*s-'0');
+                       break;
+               default:
+                       return val;
+               }
+       }
+}
+
+static int layer7_numpackets_proc_show(struct seq_file *s, void *p) {
+       seq_printf(s, "%d\n", num_packets);
+
+       return 0;
+}
+
+static int layer7_numpackets_proc_open(struct inode *inode, struct file *file) {
+       return single_open(file, layer7_numpackets_proc_show, NULL);
+}
+
+/* Read in num_packets from userland */
+static ssize_t layer7_numpackets_write_proc(struct file* file, const char __user *buffer,
+               size_t count, loff_t *data) {
+       char value[1024];
+       int new_num_packets;
+
+       if (copy_from_user(&value, buffer, sizeof(value)))
+               return -EFAULT;
+
+       new_num_packets = my_atoi(value);
+
+       if ((new_num_packets < 1) || (new_num_packets > 99)) {
+               printk(KERN_WARNING "layer7: numpackets must be between 1 and 99\n");
+               return -EFAULT;
+       }
+
+       num_packets = new_num_packets;
+
+       return count;
+}
+
+static bool
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 35)
+match(const struct sk_buff *skbin, struct xt_action_param *par)
+#elif LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+match(const struct sk_buff *skbin, const struct xt_match_param *par)
+#else
+match(const struct sk_buff *skbin,
+      const struct net_device *in,
+      const struct net_device *out,
+      const struct xt_match *match,
+      const void *matchinfo,
+      int offset,
+      unsigned int protoff,
+      bool *hotdrop)
+#endif
+{
+       /* sidestep const without getting a compiler warning... */
+       struct sk_buff * skb = (struct sk_buff *)skbin; 
+
+       const struct xt_layer7_info * info = 
+       #if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+               par->matchinfo;
+       #else
+               matchinfo;
+       #endif
+
+       enum ip_conntrack_info master_ctinfo, ctinfo;
+       struct nf_conn *master_conntrack, *conntrack;
+       unsigned char * app_data;
+       unsigned int pattern_result, appdatalen;
+       regexp * comppattern;
+
+       /* Be paranoid/incompetent - lock the entire match function. */
+       spin_lock_bh(&l7_lock);
+
+       if(!can_handle(skb)){
+               DPRINTK("layer7: This is some protocol I can't handle.\n");
+               spin_unlock_bh(&l7_lock);
+               return info->invert;
+       }
+
+       /* Treat parent & all its children together as one connection, except
+       for the purpose of setting conntrack->layer7.app_proto in the actual
+       connection. This makes /proc/net/ip_conntrack more satisfying. */
+       if(!(conntrack = nf_ct_get(skb, &ctinfo)) ||
+          !(master_conntrack=nf_ct_get(skb,&master_ctinfo))){
+               DPRINTK("layer7: couldn't get conntrack.\n");
+               spin_unlock_bh(&l7_lock);
+               return info->invert;
+       }
+
+       /* Try to get a master conntrack (and its master etc) for FTP, etc. */
+       while (master_ct(master_conntrack) != NULL)
+               master_conntrack = master_ct(master_conntrack);
+
+       /* if we've classified it or seen too many packets */
+       if(total_acct_packets(master_conntrack) > num_packets ||
+          master_conntrack->layer7.app_proto) {
+
+               pattern_result = match_no_append(conntrack, master_conntrack, 
+                                                ctinfo, master_ctinfo, info);
+
+               /* skb->cb[0] == seen. Don't do things twice if there are 
+               multiple l7 rules. I'm not sure that using cb for this purpose 
+               is correct, even though it says "put your private variables 
+               there". But it doesn't look like it is being used for anything
+               else in the skbs that make it here. */
+               skb->cb[0] = 1; /* marking it seen here's probably irrelevant */
+
+               spin_unlock_bh(&l7_lock);
+               return (pattern_result ^ info->invert);
+       }
+
+       if(skb_is_nonlinear(skb)){
+               if(skb_linearize(skb) != 0){
+                       if (net_ratelimit())
+                               printk(KERN_ERR "layer7: failed to linearize "
+                                               "packet, bailing.\n");
+                       spin_unlock_bh(&l7_lock);
+                       return info->invert;
+               }
+       }
+
+       /* now that the skb is linearized, it's safe to set these. */
+       app_data = skb->data + app_data_offset(skb);
+       appdatalen = skb_tail_pointer(skb) - app_data;
+
+       /* the return value gets checked later, when we're ready to use it */
+       comppattern = compile_and_cache(info->pattern, info->protocol);
+
+       /* On the first packet of a connection, allocate space for app data */
+       if(total_acct_packets(master_conntrack) == 1 && !skb->cb[0] && 
+          !master_conntrack->layer7.app_data){
+               master_conntrack->layer7.app_data = 
+                       kmalloc(maxdatalen, GFP_ATOMIC);
+               if(!master_conntrack->layer7.app_data){
+                       if (net_ratelimit())
+                               printk(KERN_ERR "layer7: out of memory in "
+                                               "match, bailing.\n");
+                       spin_unlock_bh(&l7_lock);
+                       return info->invert;
+               }
+
+               master_conntrack->layer7.app_data[0] = '\0';
+       }
+
+       /* Can be here, but unallocated, if numpackets is increased near
+       the beginning of a connection */
+       if(master_conntrack->layer7.app_data == NULL){
+               spin_unlock_bh(&l7_lock);
+               return info->invert; /* unmatched */
+       }
+
+       if(!skb->cb[0]){
+               int newbytes;
+               newbytes = add_data(master_conntrack, app_data, appdatalen);
+
+               if(newbytes == 0) { /* didn't add any data */
+                       skb->cb[0] = 1;
+                       /* Didn't match before, not going to match now */
+                       spin_unlock_bh(&l7_lock);
+                       return info->invert;
+               }
+       }
+
+       /* If looking for "unknown", then never match.  "Unknown" means that
+       we've given up; we're still trying with these packets. */
+       if(!strcmp(info->protocol, "unknown")) {
+               pattern_result = 0;
+       /* If looking for "unset", then always match. "Unset" means that we
+       haven't yet classified the connection. */
+       } else if(!strcmp(info->protocol, "unset")) {
+               pattern_result = 2;
+               DPRINTK("layer7: matched unset: not yet classified "
+                       "(%d/%d packets)\n",
+                        total_acct_packets(master_conntrack), num_packets);
+       /* If the regexp failed to compile, don't bother running it */
+       } else if(comppattern && 
+                 regexec(comppattern, master_conntrack->layer7.app_data)){
+               DPRINTK("layer7: matched %s\n", info->protocol);
+               pattern_result = 1;
+       } else pattern_result = 0;
+
+       if(pattern_result == 1) {
+               master_conntrack->layer7.app_proto = 
+                       kmalloc(strlen(info->protocol)+1, GFP_ATOMIC);
+               if(!master_conntrack->layer7.app_proto){
+                       if (net_ratelimit())
+                               printk(KERN_ERR "layer7: out of memory in "
+                                               "match, bailing.\n");
+                       spin_unlock_bh(&l7_lock);
+                       return (pattern_result ^ info->invert);
+               }
+               strcpy(master_conntrack->layer7.app_proto, info->protocol);
+       } else if(pattern_result > 1) { /* cleanup from "unset" */
+               pattern_result = 1;
+       }
+
+       /* mark the packet seen */
+       skb->cb[0] = 1;
+
+       spin_unlock_bh(&l7_lock);
+       return (pattern_result ^ info->invert);
+}
+
+// load nf_conntrack_ipv4
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 35)
+static int
+#else
+static bool
+#endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+check(const struct xt_mtchk_param *par)
+{
+        if (nf_ct_l3proto_try_module_get(par->match->family) < 0) {
+                printk(KERN_WARNING "can't load conntrack support for "
+                                    "proto=%d\n", par->match->family);
+#else
+check(const char *tablename, const void *inf,
+                const struct xt_match *match, void *matchinfo,
+                unsigned int hook_mask)
+{
+        if (nf_ct_l3proto_try_module_get(match->family) < 0) {
+                printk(KERN_WARNING "can't load conntrack support for "
+                                    "proto=%d\n", match->family);
+#endif
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 35)
+               return -EINVAL;
+       }
+       return 0;
+#else
+                return 0;
+        }
+       return 1;
+#endif
+}
+
+
+#if LINUX_VERSION_CODE >= KERNEL_VERSION(2, 6, 28)
+       static void destroy(const struct xt_mtdtor_param *par)
+       {
+               nf_ct_l3proto_module_put(par->match->family);
+       }
+#else
+       static void destroy(const struct xt_match *match, void *matchinfo)
+       {
+               nf_ct_l3proto_module_put(match->family);
+       }
+#endif
+
+static struct xt_match xt_layer7_match[] __read_mostly = {
+{
+       .name           = "layer7",
+       .family         = NFPROTO_IPV4,
+       .checkentry     = check,
+       .match          = match,
+       .destroy        = destroy,
+       .matchsize      = sizeof(struct xt_layer7_info),
+       .me             = THIS_MODULE
+}
+};
+
+static const struct file_operations layer7_numpackets_proc_fops = {
+       .owner   = THIS_MODULE,
+       .open    = layer7_numpackets_proc_open,
+       .read    = seq_read,
+       .llseek  = seq_lseek,
+       .release = single_release,
+       .write   = layer7_numpackets_write_proc,
+};
+
+static int __init xt_layer7_init(void)
+{
+       need_conntrack();
+
+       // Register proc interface
+       proc_create_data("layer7_numpackets", 0644,
+               init_net.proc_net, &layer7_numpackets_proc_fops, NULL);
+
+       if(maxdatalen < 1) {
+               printk(KERN_WARNING "layer7: maxdatalen can't be < 1, "
+                       "using 1\n");
+               maxdatalen = 1;
+       }
+       /* This is not a hard limit.  It's just here to prevent people from
+       bringing their slow machines to a grinding halt. */
+       else if(maxdatalen > 65536) {
+               printk(KERN_WARNING "layer7: maxdatalen can't be > 65536, "
+                       "using 65536\n");
+               maxdatalen = 65536;
+       }
+       return xt_register_matches(xt_layer7_match,
+                                  ARRAY_SIZE(xt_layer7_match));
+}
+
+static void __exit xt_layer7_fini(void)
+{
+       remove_proc_entry("layer7_numpackets", init_net.proc_net);
+       xt_unregister_matches(xt_layer7_match, ARRAY_SIZE(xt_layer7_match));
+}
+
+module_init(xt_layer7_init);
+module_exit(xt_layer7_fini);
+