A packed AppArmor policy contains null-terminated tag strings that are read
by unpack_nameX(). However, unpack_nameX() uses string functions on them
without ensuring that they are actually null-terminated, potentially
leading to out-of-bounds accesses.
Make sure that the tag string is null-terminated before passing it to
strcmp().
Cc: sta...@vger.kernel.org
Signed-off-by: Jann Horn <ja...@google.com>
---
Warning: The existence of this bug has not been verified at runtime, and
the patch is compile-tested only. I noticed this while browsing through
the code, but didn't want to spend the time necessary to figure out how
to actually test this at runtime.
security/apparmor/policy_unpack.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/security/apparmor/policy_unpack.c
b/security/apparmor/policy_unpack.c
index f6c2bcb2ab14..33041c4fb69f 100644
--- a/security/apparmor/policy_unpack.c
+++ b/security/apparmor/policy_unpack.c
@@ -276,7 +276,7 @@ static bool unpack_nameX(struct aa_ext *e, enum aa_code
code, const char *name)
char *tag = NULL;
size_t size = unpack_u16_chunk(e, &tag);
/* if a name is specified it must match. otherwise skip tag */
- if (name && (!size || strcmp(name, tag)))
+ if (name && (!size || tag[size-1] != '\0' || strcmp(name, tag)))
goto fail;
} else if (name) {
/* if a name is specified and there is no name tag fail */
--
2.22.0.rc1.257.g3120a18244-goog
