Add support for extracting SCHIL.xattr extended attributes

This patch adds support for extracting SCHIL.xattr extended attributes
found in the PAX extended header. Since some of the attributes found
there can be binary data, we extend the parser for support of binary data.

One example for an attribute with binary data is SCHILY.xattr.security.ima,
which contains a digital signature.

Signed-off-by: Stefan Berger <stefanb@linux.vnet.ibm.com>

diff --git a/libarchive/archive_read_support_format_tar.c b/libarchive/archive_read_support_format_tar.c
index b18edcc12029b832ebbfbd400cf2202b4032f643..33732530f8b9b283ef23beeacbe49ad0ce9b084d 100644 (file)
--- a/libarchive/archive_read_support_format_tar.c
+++ b/libarchive/archive_read_support_format_tar.c
@@ -204,13 +204,14 @@ static int        archive_read_format_tar_read_header(struct archive_read *,
                    struct archive_entry *);
 static int     checksum(struct archive_read *, const void *);
 static int     pax_attribute(struct archive_read *, struct tar *,
-                   struct archive_entry *, const char *key, const char *value);
+                   struct archive_entry *, const char *key, const char *value,
+                   size_t value_length);
 static int     pax_attribute_acl(struct archive_read *, struct tar *,
                    struct archive_entry *, const char *, int);
 static int     pax_attribute_xattr(struct archive_entry *, const char *,
                    const char *);
 static int     pax_header(struct archive_read *, struct tar *,
-                   struct archive_entry *, char *attr);
+                   struct archive_entry *, struct archive_string *);
 static void    pax_time(const char *, int64_t *sec, long *nanos);
 static ssize_t readline(struct archive_read *, struct tar *, const char **,
                    ssize_t limit, size_t *);
@@ -1483,7 +1484,7 @@ header_pax_extensions(struct archive_read *a, struct tar *tar,
         * and then skip any fields in the standard header that were
         * defined in the pax header.
         */
-       err2 = pax_header(a, tar, entry, tar->pax_header.s);
+       err2 = pax_header(a, tar, entry, &tar->pax_header);
        err =  err_combine(err, err2);
        tar->entry_padding = 0x1ff & (-tar->entry_bytes_remaining);
        return (err);
@@ -1564,16 +1565,17 @@ header_ustar(struct archive_read *a, struct tar *tar,
  */
 static int
 pax_header(struct archive_read *a, struct tar *tar,
-    struct archive_entry *entry, char *attr)
+    struct archive_entry *entry, struct archive_string *in_as)
 {
-       size_t attr_length, l, line_length;
+       size_t attr_length, l, line_length, value_length;
        char *p;
        char *key, *value;
        struct archive_string *as;
        struct archive_string_conv *sconv;
        int err, err2;
+       char *attr = in_as->s;
 
-       attr_length = strlen(attr);
+       attr_length = in_as->length;
        tar->pax_hdrcharset_binary = 0;
        archive_string_empty(&(tar->entry_gname));
        archive_string_empty(&(tar->entry_linkpath));
@@ -1638,11 +1640,13 @@ pax_header(struct archive_read *a, struct tar *tar,
                }
                *p = '\0';
 
-               /* Identify null-terminated 'value' portion. */
                value = p + 1;
 
+               /* Some values may be binary data */
+               value_length = attr + line_length - 1 - value;
+
                /* Identify this attribute and set it in the entry. */
-               err2 = pax_attribute(a, tar, entry, key, value);
+               err2 = pax_attribute(a, tar, entry, key, value, value_length);
                if (err2 == ARCHIVE_FATAL)
                        return (err2);
                err = err_combine(err, err2);
@@ -1763,6 +1767,20 @@ pax_attribute_xattr(struct archive_entry *entry,
        return 0;
 }
 
+static int
+pax_attribute_schily_xattr(struct archive_entry *entry,
+       const char *name, const char *value, size_t value_length)
+{
+       if (strlen(name) < 14 || (memcmp(name, "SCHILY.xattr.", 13)) != 0)
+               return 1;
+
+       name += 13;
+
+       archive_entry_xattr_add_entry(entry, name, value, value_length);
+
+       return 0;
+}
+
 static int
 pax_attribute_acl(struct archive_read *a, struct tar *tar,
     struct archive_entry *entry, const char *value, int type)
@@ -1824,7 +1842,7 @@ pax_attribute_acl(struct archive_read *a, struct tar *tar,
  */
 static int
 pax_attribute(struct archive_read *a, struct tar *tar,
-    struct archive_entry *entry, const char *key, const char *value)
+    struct archive_entry *entry, const char *key, const char *value, size_t value_length)
 {
        int64_t s;
        long n;
@@ -1959,6 +1977,9 @@ pax_attribute(struct archive_read *a, struct tar *tar,
                } else if (strcmp(key, "SCHILY.realsize") == 0) {
                        tar->realsize = tar_atol10(value, strlen(value));
                        archive_entry_set_size(entry, tar->realsize);
+               } else if (strncmp(key, "SCHILY.xattr.", 13) == 0) {
+                       pax_attribute_schily_xattr(entry, key, value,
+                           value_length);
                } else if (strcmp(key, "SUN.holesdata") == 0) {
                        /* A Solaris extension for sparse. */
                        r = solaris_sparse_parse(a, tar, entry, value);