From afe5d5a747393cb3d00795db31d7fce5108a766a Mon Sep 17 00:00:00 2001 From: Guanglei Zhu Date: Wed, 16 Sep 2026 19:53:07 +0800 Subject: [PATCH] apparmor: check accept index + 1 is in bounds aa_lookup_condperms() returns perms[index + 1] when an accept entry has ACCEPT_FLAG_OWNER set and the subject uid does not match the file uid, so such an entry consumes two slots in the perms table. But verify_dfa_accept_index() only checks that index is within the perms table, so a policy that sets the owner flag on the last entry is accepted, and the runtime lookup then reads perms[index + 1] one entry past the end of the table. The perms table is allocated by unpack_perms_table() with a u16 size read from the policy blob, so a crafted policy can place the owner flag at index size - 1 to reach the out-of-bounds read. Check that index + 1 is also in bounds when the owner flag is set. Fixes: 6f442d42c0d89 ("apparmor: fix profile verification and enable it") Cc: stable@vger.kernel.org Signed-off-by: Guanglei Zhu Signed-off-by: John Johansen --- security/apparmor/policy_unpack.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/security/apparmor/policy_unpack.c b/security/apparmor/policy_unpack.c index 3ffbab46eec3..7ebffb4ff74f 100644 --- a/security/apparmor/policy_unpack.c +++ b/security/apparmor/policy_unpack.c @@ -1495,6 +1495,15 @@ static bool verify_dfa_accept_index(const struct aa_dfa *dfa, int table_size) for (i = 0; i < dfa->tables[YYTD_ID_ACCEPT]->td_lolen; i++) { if (ACCEPT_TABLE(dfa)[i] >= table_size) return false; + /* + * Accept indexes for owner-conditional permissions come in + * pairs, so the non-owner entry at index + 1 must also be + * in bounds. + */ + if (dfa->tables[YYTD_ID_ACCEPT2] && + (ACCEPT_TABLE2(dfa)[i] & ACCEPT_FLAG_OWNER) && + ACCEPT_TABLE(dfa)[i] + 1 >= table_size) + return false; } return true; }