From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 474671D5CC6 for ; Mon, 15 Jun 2026 07:49:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781509742; cv=none; b=dAdFHETh0I9EsQ/SJJa90u9eAX1Ls0qo6EOMNvf/zOO8ZJSuF8aqpFtNp6gxsKw2FLPinmpo3oL0SOJL7Co74GdMh/Bh21CRKMfwlV5/btO8iWz8DVvokzVdfrFiiQYj4tN70gd9wpMMf8VGiI01lqR6hGf+8xRBY0JwKewjMak= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781509742; c=relaxed/simple; bh=G7F0f8T1M99OdsE14Y0ratx+JKnqsYMQzZZUcbKHUFM=; h=Message-ID:Date:MIME-Version:Cc:Subject:To:References:From: In-Reply-To:Content-Type; b=eP5VFFt3zEkEaFlgGYU2ww6CADfmvYgl/NUccRsqNXYKsgCosNu4Dr20XXFLlh5aqxtv8qXTRZASfOnRLrFA9ykAV+U1QX59ByiUndYqivbiHEkwdk6hNcTqM5VaRELD/EQ09PT66G4dkrxwb6508swRDOvlOjBKva6Law3ajKs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=m0KXl6qe; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="m0KXl6qe" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6E6261F00A3A; Mon, 15 Jun 2026 07:48:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1781509740; bh=gfi3SSV00neQWQKyfC4FDKdat0tZ0INV/4KF5gThayU=; h=Date:Cc:Subject:To:References:From:In-Reply-To; b=m0KXl6qenWKYS+AN0RebwUPQcuk8TLMz8x9no/6+PC8UoXtHrbCcLC9M60n8JSjzO mq4BUvVh8LYWLxvouMem5r0+PGhiSOf2Tt7jZvUHSB/9IE2LVguys4uTdBAHPAqj8d u+3RduM4XvvDNRbclc8bpjkxpO9pnIZ3WQH5F6zO250i70261nBaaGV24b54/C7Roa U0Jd76s4p8mN0dIDn1SoxGcOz1/etRfzwSAuZOuHxIcErW3uKzuhxlBCbnkHKCmY7O 3Ey/2kpvIlPri4329zrFGjlK9PwYR520w1dFSsrMjJQ7sTG51pqx4m5qjWmRe5BNbp mP0Q3cpP3VTeA== Message-ID: Date: Mon, 15 Jun 2026 15:48:57 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Cc: chao@kernel.org, linux-f2fs-devel@lists.sourceforge.net, linux-kernel@vger.kernel.org, zerocling0077@gmail.com, 2045gemini@gmail.com Subject: Re: [PATCH v3] f2fs: validate ACL entry sizes in f2fs_acl_from_disk() To: Zhang Cen , Jaegeuk Kim References: <20260615071954.4118409-1-rollkingzzc@gmail.com> Content-Language: en-US From: Chao Yu In-Reply-To: <20260615071954.4118409-1-rollkingzzc@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 6/15/26 15:19, Zhang Cen wrote: > f2fs_acl_count() only validates the aggregate ACL xattr length. A > malformed ACL can still place ACL_USER or ACL_GROUP in a slot that only > contains struct f2fs_acl_entry_short bytes, and f2fs_acl_from_disk() > then reads entry->e_id before verifying that a full entry fits. > > Require a short entry before reading e_tag and e_perm, and require a > full entry before reading e_id for ACL_USER and ACL_GROUP. Return > -EFSCORRUPTED from these new truncated-entry checks, while keeping the > pre-existing -EINVAL paths unchanged. > > Validation reproduced this kernel report: > KASAN slab-out-of-bounds in __f2fs_get_acl+0x6fb/0x7e0 > RIP: 0033:0x7f4b835ea7aa > The buggy address belongs to the object at ffff888114589960 which belongs > to the cache kmalloc-8 of size 8 > The buggy address is located 0 bytes to the right of allocated 8-byte > region [ffff888114589960, ffff888114589968) > Read of size 4 > Call trace: > dump_stack_lvl+0x66/0xa0 (?:?) > print_report+0xce/0x630 (?:?) > __f2fs_get_acl+0x6fb/0x7e0 (fs/f2fs/acl.c:169) > srso_alias_return_thunk+0x5/0xfbef5 (?:?) > __virt_addr_valid+0x224/0x430 (?:?) > kasan_report+0xe0/0x110 (?:?) > __f2fs_get_acl+0x5/0x7e0 (fs/f2fs/acl.c:169) > __get_acl+0x281/0x380 (?:?) > vfs_get_acl+0x10b/0x190 (?:?) > do_get_acl+0x2a/0x410 (?:?) > do_get_acl+0x9/0x410 (?:?) > do_getxattr+0xe8/0x260 (?:?) > filename_getxattr+0xd1/0x140 (?:?) > do_getname+0x2d/0x2d0 (?:?) > path_getxattrat+0x16c/0x200 (?:?) > lock_release+0xc8/0x290 (?:?) > cgroup_update_frozen+0x9d/0x320 (?:?) > lockdep_hardirqs_on_prepare+0xea/0x1a0 (?:?) > trace_hardirqs_on+0x1a/0x170 (?:?) > _raw_spin_unlock_irq+0x28/0x50 (?:?) > do_syscall_64+0x115/0x6a0 (arch/x86/entry/syscall_64.c:87) > entry_SYSCALL_64_after_hwframe+0x77/0x7f (?:?) > Cc: stable@kernel.org > Fixes: af48b85b8cd3 ("f2fs: add xattr and acl functionalities") > Assisted-by: Codex:gpt-5.5 > Signed-off-by: Zhang Cen Reviewed-by: Chao Yu Thanks,