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 AE4B2346A10; Mon, 13 Apr 2026 17:01:21 +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=1776099681; cv=none; b=i5HMPfvAhAnMr7TrhZZ1dU0w8J6DE2tXwQl19scsQ9D/GY7ayxPYs37sQ8SXVdiGucqqsO+qMwlCSZzlZ1vlOI6Cxii/ROOp6nMuhrNdXM9/mqih1kO9l468XkAFFuv0dMJCbfVjl2rUjYAB0gvErQOjvoD7O6diPfTCoBbtvA4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1776099681; c=relaxed/simple; bh=wrIOtJg/cjK4+qTT03SQ40WnOHg0TYzafEAyNA93bRA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=If6Egn7U3ocDOjLIfwIPSxa537EgUccHFMC+905cr84OyCYvgDs3EtNfCkvP8geItvXLMbcC0F8aNEwwvCOG5CuJsbf9soe1KWWOYtYqjGWBTIxGSniKqskUvfI5met3ntIvZasYvmHGuSeEHIRCH3cggUYvnfjzQkIWhRzTjvY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=uRU7cAlx; 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="uRU7cAlx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4249DC2BCB3; Mon, 13 Apr 2026 17:01:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1776099681; bh=wrIOtJg/cjK4+qTT03SQ40WnOHg0TYzafEAyNA93bRA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=uRU7cAlxCU+D95hQ4pgOqF0fAVkrzkZKPANKC6CnwRvamwzIimxh6SZAYcmYI4xHs 1ktA/ILUfPBPzfPwsUdKi7E8mtDiODRFqJrOTupFN2NHFeQ7DZozhCWKDnsOHfOKml igvcec7p9wnBg+GjTaprSDRmKGqcD33W333MGFwI= 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 5.10 434/491] apparmor: fix side-effect bug in match_char() macro usage Date: Mon, 13 Apr 2026 18:01:19 +0200 Message-ID: <20260413155835.276146833@linuxfoundation.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260413155819.042779211@linuxfoundation.org> References: <20260413155819.042779211@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 5.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: Massimiliano Pellizzer commit 8756b68edae37ff546c02091989a4ceab3f20abd upstream. The match_char() macro evaluates its character parameter multiple times when traversing differential encoding chains. When invoked with *str++, the string pointer advances on each iteration of the inner do-while loop, causing the DFA to check different characters at each iteration and therefore skip input characters. This results in out-of-bounds reads when the pointer advances past the input buffer boundary. [ 94.984676] ================================================================== [ 94.985301] BUG: KASAN: slab-out-of-bounds in aa_dfa_match+0x5ae/0x760 [ 94.985655] Read of size 1 at addr ffff888100342000 by task file/976 [ 94.986319] CPU: 7 UID: 1000 PID: 976 Comm: file Not tainted 6.19.0-rc7-next-20260127 #1 PREEMPT(lazy) [ 94.986322] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2 04/01/2014 [ 94.986329] Call Trace: [ 94.986341] [ 94.986347] dump_stack_lvl+0x5e/0x80 [ 94.986374] print_report+0xc8/0x270 [ 94.986384] ? aa_dfa_match+0x5ae/0x760 [ 94.986388] kasan_report+0x118/0x150 [ 94.986401] ? aa_dfa_match+0x5ae/0x760 [ 94.986405] aa_dfa_match+0x5ae/0x760 [ 94.986408] __aa_path_perm+0x131/0x400 [ 94.986418] aa_path_perm+0x219/0x2f0 [ 94.986424] apparmor_file_open+0x345/0x570 [ 94.986431] security_file_open+0x5c/0x140 [ 94.986442] do_dentry_open+0x2f6/0x1120 [ 94.986450] vfs_open+0x38/0x2b0 [ 94.986453] ? may_open+0x1e2/0x2b0 [ 94.986466] path_openat+0x231b/0x2b30 [ 94.986469] ? __x64_sys_openat+0xf8/0x130 [ 94.986477] do_file_open+0x19d/0x360 [ 94.986487] do_sys_openat2+0x98/0x100 [ 94.986491] __x64_sys_openat+0xf8/0x130 [ 94.986499] do_syscall_64+0x8e/0x660 [ 94.986515] ? count_memcg_events+0x15f/0x3c0 [ 94.986526] ? srso_alias_return_thunk+0x5/0xfbef5 [ 94.986540] ? handle_mm_fault+0x1639/0x1ef0 [ 94.986551] ? vma_start_read+0xf0/0x320 [ 94.986558] ? srso_alias_return_thunk+0x5/0xfbef5 [ 94.986561] ? srso_alias_return_thunk+0x5/0xfbef5 [ 94.986563] ? fpregs_assert_state_consistent+0x50/0xe0 [ 94.986572] ? srso_alias_return_thunk+0x5/0xfbef5 [ 94.986574] ? arch_exit_to_user_mode_prepare+0x9/0xb0 [ 94.986587] ? srso_alias_return_thunk+0x5/0xfbef5 [ 94.986588] ? irqentry_exit+0x3c/0x590 [ 94.986595] entry_SYSCALL_64_after_hwframe+0x76/0x7e [ 94.986597] RIP: 0033:0x7fda4a79c3ea Fix by extracting the character value before invoking match_char, ensuring single evaluation per outer loop. Fixes: 074c1cd798cb ("apparmor: dfa move character match into a macro") 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/match.c | 30 ++++++++++++++++++++---------- 1 file changed, 20 insertions(+), 10 deletions(-) --- a/security/apparmor/match.c +++ b/security/apparmor/match.c @@ -452,13 +452,18 @@ unsigned int aa_dfa_match_len(struct aa_ if (dfa->tables[YYTD_ID_EC]) { /* Equivalence class table defined */ u8 *equiv = EQUIV_TABLE(dfa); - for (; len; len--) - match_char(state, def, base, next, check, - equiv[(u8) *str++]); + for (; len; len--) { + u8 c = equiv[(u8) *str]; + + match_char(state, def, base, next, check, c); + str++; + } } else { /* default is direct to next state */ - for (; len; len--) - match_char(state, def, base, next, check, (u8) *str++); + for (; len; len--) { + match_char(state, def, base, next, check, (u8) *str); + str++; + } } return state; @@ -493,13 +498,18 @@ unsigned int aa_dfa_match(struct aa_dfa /* Equivalence class table defined */ u8 *equiv = EQUIV_TABLE(dfa); /* default is direct to next state */ - while (*str) - match_char(state, def, base, next, check, - equiv[(u8) *str++]); + while (*str) { + u8 c = equiv[(u8) *str]; + + match_char(state, def, base, next, check, c); + str++; + } } else { /* default is direct to next state */ - while (*str) - match_char(state, def, base, next, check, (u8) *str++); + while (*str) { + match_char(state, def, base, next, check, (u8) *str); + str++; + } } return state;