4.4-stable patches

added patches:
	x86-uprobes-do-not-use-prefixes.nbytes-when-looping-over-prefixes.bytes.patch

diff --git a/queue-4.4/series b/queue-4.4/series
index e99a5466c243db2b46ca7da438a4c3fa579148b8..f552b8d55a068d7978e266905bf901a2c124b9b4 100644 (file)
--- a/queue-4.4/series
+++ b/queue-4.4/series
@@ -36,3 +36,4 @@ btrfs-cleanup-cow-block-on-error.patch
 mm-userfaultfd-do-not-access-vma-vm_mm-after-calling-handle_userfault.patch
 gfs2-check-for-empty-rgrp-tree-in-gfs2_ri_update.patch
 input-i8042-fix-error-return-code-in-i8042_setup_aux.patch
+x86-uprobes-do-not-use-prefixes.nbytes-when-looping-over-prefixes.bytes.patch

diff --git a/queue-4.4/x86-uprobes-do-not-use-prefixes.nbytes-when-looping-over-prefixes.bytes.patch b/queue-4.4/x86-uprobes-do-not-use-prefixes.nbytes-when-looping-over-prefixes.bytes.patch
new file mode 100644 (file)
index 0000000..154f816
--- /dev/null
+++ b/queue-4.4/x86-uprobes-do-not-use-prefixes.nbytes-when-looping-over-prefixes.bytes.patch
@@ -0,0 +1,97 @@
+From foo@baz Thu Dec 10 03:08:33 PM CET 2020
+From: Masami Hiramatsu <mhiramat@kernel.org>
+Date: Thu, 3 Dec 2020 13:50:37 +0900
+Subject: x86/uprobes: Do not use prefixes.nbytes when looping over prefixes.bytes
+
+From: Masami Hiramatsu <mhiramat@kernel.org>
+
+commit 4e9a5ae8df5b3365183150f6df49e49dece80d8c upstream
+
+Since insn.prefixes.nbytes can be bigger than the size of
+insn.prefixes.bytes[] when a prefix is repeated, the proper check must
+be
+
+  insn.prefixes.bytes[i] != 0 and i < 4
+
+instead of using insn.prefixes.nbytes.
+
+Introduce a for_each_insn_prefix() macro for this purpose. Debugged by
+Kees Cook <keescook@chromium.org>.
+
+ [ bp: Massage commit message, sync with the respective header in tools/
+   and drop "we". ]
+
+Fixes: 2b1444983508 ("uprobes, mm, x86: Add the ability to install and remove uprobes breakpoints")
+Reported-by: syzbot+9b64b619f10f19d19a7c@syzkaller.appspotmail.com
+Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
+Signed-off-by: Borislav Petkov <bp@suse.de>
+Reviewed-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
+Cc: stable@vger.kernel.org
+Link: https://lkml.kernel.org/r/160697103739.3146288.7437620795200799020.stgit@devnote2
+[sudip: adjust context, drop change of insn.h in tools]
+Signed-off-by: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ arch/x86/include/asm/insn.h |   15 +++++++++++++++
+ arch/x86/kernel/uprobes.c   |   10 ++++++----
+ 2 files changed, 21 insertions(+), 4 deletions(-)
+
+--- a/arch/x86/include/asm/insn.h
++++ b/arch/x86/include/asm/insn.h
+@@ -198,6 +198,21 @@ static inline int insn_offset_immediate(
+       return insn_offset_displacement(insn) + insn->displacement.nbytes;
+ }
+ 
++/**
++ * for_each_insn_prefix() -- Iterate prefixes in the instruction
++ * @insn: Pointer to struct insn.
++ * @idx:  Index storage.
++ * @prefix: Prefix byte.
++ *
++ * Iterate prefix bytes of given @insn. Each prefix byte is stored in @prefix
++ * and the index is stored in @idx (note that this @idx is just for a cursor,
++ * do not change it.)
++ * Since prefixes.nbytes can be bigger than 4 if some prefixes
++ * are repeated, it cannot be used for looping over the prefixes.
++ */
++#define for_each_insn_prefix(insn, idx, prefix)       \
++      for (idx = 0; idx < ARRAY_SIZE(insn->prefixes.bytes) && (prefix = insn->prefixes.bytes[idx]) != 0; idx++)
++
+ #define POP_SS_OPCODE 0x1f
+ #define MOV_SREG_OPCODE 0x8e
+ 
+--- a/arch/x86/kernel/uprobes.c
++++ b/arch/x86/kernel/uprobes.c
+@@ -268,10 +268,11 @@ static volatile u32 good_2byte_insns[256
+ 
+ static bool is_prefix_bad(struct insn *insn)
+ {
++      insn_byte_t p;
+       int i;
+ 
+-      for (i = 0; i < insn->prefixes.nbytes; i++) {
+-              switch (insn->prefixes.bytes[i]) {
++      for_each_insn_prefix(insn, i, p) {
++              switch (p) {
+               case 0x26:      /* INAT_PFX_ES   */
+               case 0x2E:      /* INAT_PFX_CS   */
+               case 0x36:      /* INAT_PFX_DS   */
+@@ -711,6 +712,7 @@ static struct uprobe_xol_ops branch_xol_
+ static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn)
+ {
+       u8 opc1 = OPCODE1(insn);
++      insn_byte_t p;
+       int i;
+ 
+       switch (opc1) {
+@@ -741,8 +743,8 @@ static int branch_setup_xol_ops(struct a
+        * Intel and AMD behavior differ in 64-bit mode: Intel ignores 66 prefix.
+        * No one uses these insns, reject any branch insns with such prefix.
+        */
+-      for (i = 0; i < insn->prefixes.nbytes; i++) {
+-              if (insn->prefixes.bytes[i] == 0x66)
++      for_each_insn_prefix(insn, i, p) {
++              if (p == 0x66)
+                       return -ENOTSUPP;
+       }
+