From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 912532C17A0; Thu, 12 Mar 2026 20:05:24 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773345924; cv=none; b=lCJu4wdQT3gUCEW2Qmluz8yjzc1S0j3xYPSdVevXwdbb2uXVet5lVgV8Ynv8MATi/PuX663h0P2/eW73uSZEfvjDRTq6o+iTZpCjp5a2uvWV3KHSc4RLMBVTq7VpRi++Kp1wDOIIh+X/b1eONUbirwn7kt6N6wR300KTx8FzxdE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773345924; c=relaxed/simple; bh=lDN0jm9mcschecbOir74/VpX5hNwz4SIW1huc4ISwYI=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=aazYSbEPaFmMREYyq4k4AIAiwZicFG875TTwM5BXtb0UOvtMRz2wUQvp5Lv+Ahsodgx5f1ew/MymfTHXc+qRTEPAlN1Ar29M+vpEgRqs5MFnslW0B4zKsVW7kcUQSNX155fmNSH2BFRepdAKAtNQmj8t4Ikn+A0ByPrJMZfBGZs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BJ4ZfjL5; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BJ4ZfjL5" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D7DE7C2BC87; Thu, 12 Mar 2026 20:05:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1773345924; bh=lDN0jm9mcschecbOir74/VpX5hNwz4SIW1huc4ISwYI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=BJ4ZfjL5trgFfR67S2JbO2tfuCGcWvm/BFuqE9LcFuhWmM9yWBaJirJkJBY8HI65d Qhukrz6Xlg4tGZkvotZYZ0w6rsEFwru0Y0qItCUonnSVWz7vxs+dSXyVYwsTZe6ujB KSSofmi+H+EXfWYYeGo1lVp29fwFuuTCghtluqd0= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Qualys Security Advisory , Salvatore Bonaccorso , Georgia Garcia , Cengiz Can , Massimiliano Pellizzer , John Johansen Subject: [PATCH 6.18 03/13] apparmor: validate DFA start states are in bounds in unpack_pdb Date: Thu, 12 Mar 2026 21:03:44 +0100 Message-ID: <20260312200326.373092108@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260312200326.246396673@linuxfoundation.org> References: <20260312200326.246396673@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Massimiliano Pellizzer commit 9063d7e2615f4a7ab321de6b520e23d370e58816 upstream. Start states are read from untrusted data and used as indexes into the DFA state tables. The aa_dfa_next() function call in unpack_pdb() will access dfa->tables[YYTD_ID_BASE][start], and if the start state exceeds the number of states in the DFA, this results in an out-of-bound read. ================================================================== BUG: KASAN: slab-out-of-bounds in aa_dfa_next+0x2a1/0x360 Read of size 4 at addr ffff88811956fb90 by task su/1097 ... Reject policies with out-of-bounds start states during unpacking to prevent the issue. Fixes: ad5ff3db53c6 ("AppArmor: Add ability to load extended policy") Reported-by: Qualys Security Advisory Tested-by: Salvatore Bonaccorso Reviewed-by: Georgia Garcia Reviewed-by: Cengiz Can Signed-off-by: Massimiliano Pellizzer Signed-off-by: John Johansen Signed-off-by: Greg Kroah-Hartman --- security/apparmor/policy_unpack.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-) --- a/security/apparmor/policy_unpack.c +++ b/security/apparmor/policy_unpack.c @@ -770,7 +770,17 @@ static int unpack_pdb(struct aa_ext *e, if (!aa_unpack_u32(e, &pdb->start[AA_CLASS_FILE], "dfa_start")) { /* default start state for xmatch and file dfa */ pdb->start[AA_CLASS_FILE] = DFA_START; - } /* setup class index */ + } + + size_t state_count = pdb->dfa->tables[YYTD_ID_BASE]->td_lolen; + + if (pdb->start[0] >= state_count || + pdb->start[AA_CLASS_FILE] >= state_count) { + *info = "invalid dfa start state"; + goto fail; + } + + /* setup class index */ for (i = AA_CLASS_FILE + 1; i <= AA_CLASS_LAST; i++) { pdb->start[i] = aa_dfa_next(pdb->dfa, pdb->start[0], i);