From: Jann Horn jannh@google.com
commit 8404d7a674c49278607d19726e0acc0cae299357 upstream.
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 jannh@google.com Signed-off-by: John Johansen john.johansen@canonical.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- security/apparmor/policy_unpack.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/security/apparmor/policy_unpack.c +++ b/security/apparmor/policy_unpack.c @@ -177,7 +177,7 @@ static bool unpack_nameX(struct aa_ext * 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 */