From 8404d7a674c49278607d19726e0acc0cae299357 Mon Sep 17 00:00:00 2001 From: Jann Horn Date: Tue, 28 May 2019 17:32:26 +0200 Subject: [PATCH] apparmor: enforce nullbyte at end of tag string 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: stable@vger.kernel.org Fixes: 736ec752d95e ("AppArmor: policy routines for loading and unpacking policy") Signed-off-by: Jann Horn Signed-off-by: John Johansen --- 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 01957ce9252b5..005a705346f05 100644 --- a/security/apparmor/policy_unpack.c +++ b/security/apparmor/policy_unpack.c @@ -272,7 +272,7 @@ 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 */ -- 2.39.2