From patchwork Fri Apr 4 05:31:29 2025 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Edward Adam Davis X-Patchwork-Id: 14038148 Received: from out162-62-57-210.mail.qq.com (out162-62-57-210.mail.qq.com [162.62.57.210]) (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 2939DDDC1; Fri, 4 Apr 2025 05:37:40 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=162.62.57.210 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743745066; cv=none; b=R2FbgTYmo4rvS9lehGKP1ka46f2KtyCUDNVfHBwUtAVmngA370XYRAvH0tbCbDZEIqPOHncP3bGx+1wtIcC0u4V/288EBzNZoI2Any6PBO9vyWLI6XMccdtKfVC/9nhCWjKoLXST6kBm+cSnC0bATH1ZGZVgriu1EVk6rdJsyC0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1743745066; c=relaxed/simple; bh=v2K3Ci6Hqa/XaBgTwF7fn5YXxKcOQtRT8RTrXCQP4Cw=; h=Message-ID:From:To:Cc:Subject:Date:In-Reply-To:References: MIME-Version; b=EwzXoj9dnjyP0Wst/vAntHYGtGeHusAnW8uXdwSN1hoEHbWTQttgOeWsG2pp4xOsfnGka3vt0VoeoPNMTmsZV1KiquKDuwyM3HAgKBn3ocUICrMQBuH2E/lok0kjYyET7wdEHLkqb3Zt8YPtNmy2fqft5oMuG5P/ep0BTcUNdx4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com; spf=pass smtp.mailfrom=qq.com; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b=lEjdKZB1; arc=none smtp.client-ip=162.62.57.210 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=qq.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=qq.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=qq.com header.i=@qq.com header.b="lEjdKZB1" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=qq.com; s=s201512; t=1743745056; bh=wrSj9PzWh2wVzoWv3XkhoWrvov00Rs2DfdHlLI0RZ/k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=lEjdKZB11l3Mx7QWXWEFV84QBrUlzgPRk6ngIRu/ZAnVTJquac7Wkfm5D491TaPC4 bMf/5SqLd1BDuqpSjET/W8CCl0gNiUSeLW5z3EtSNxKSqWrcZ3ethUP1F+DnbvI+sH u5EU9aCuwEoI7toUPi1maCZQT/t5eK8pDhuXAnpE= Received: from pek-lxu-l1.wrs.com ([114.244.57.157]) by newxmesmtplogicsvrszc13-0.qq.com (NewEsmtp) with SMTP id 7DCAA611; Fri, 04 Apr 2025 13:31:28 +0800 X-QQ-mid: xmsmtpt1743744688tomd71bwx Message-ID: X-QQ-XMAILINFO: MiwL2wmyONS9vtXwWrRJ1j3yBQKHJJvDrdoSgeiSARMKVgikB3klDMnagz4rab 9Utwb0i2hGs0PnYpOh9ZFzfaYTj3VtD7g9zoPHIcamlzaHFIEjxD6wRx+NSMVsGsVg9bcHYxDSQv gfUrXQRo/fncdt5xei+d8uML0vouOHMFLSaLIc35lbwzV9Hjd/66riDveY0t3H4ZhIuyyjXHLkMF csUVT2Gijz/AY9rdDSfOGBhagWpPKFur8RVz58G/3NszzY3IwjoVS7yq7YdWRXsmd2mS+7DKK35N QvmyjmZt3hkEedNUKLL9fYgOX+x6mGhjHHVfNCxi0c6NCMtjQCGOBnodHhQ/eWh7YQNW6IwxetZj ZeCDmEn1PEnbNZZPNswUfYeccI4yS0hlvwuSkeuzPTp7oDEFbrV4H4rax7VY5JBKNVoGcmCEWwu3 msKkRd2dK5xn8UXPhmixWJJ0oVmzz2pDk0sIPdeV4+ECYJj7ja8WdjJsmFaC8/kSYakQ+SRuZx50 bp+mARe0uVOSdvs7fUNiSNvykVRHHu5Mqoi9MnfTsDKi3ANucO1+R5G1bgrg8qBNQIpEKcUBVuS9 CVLYdpUn4pCXga/eUPN7BcM9s4oZ6vnZB4fhNZjTAvyGVmBh2kFLOXa9TsrbFhuYmlYvDXu97N26 zRmEXgYrxqUb+25rilvfaFGW9Nhm7pARKbD4qun8dY8cQyJm3BX7mRgd11kd4zzRA3F7W6TOCa9J AV6A16ctJd+DGWKNBa3XRjgHFxFMmwneUk4TYfQviThywESBxluedaAj9zI+7Nz+I/EqgszIiJkp N5owYYKYYqqURgndfLBioxVvA8LuEg1ZeP/qMxl3fL68/8x5BnHL9a9vjNZVruf9XudNQNWOb4hW BgrLSM3fCY/mA05dodmlt7JIuPTuzOKZfk10/7gyOxEYf+8alYur9kIZNW6GU8IlM1R+bFsc41 X-QQ-XMRINFO: Mp0Kj//9VHAxr69bL5MkOOs= From: Edward Adam Davis To: syzbot+4d7cd7dd0ce1aa8d5c65@syzkaller.appspotmail.com Cc: jack@suse.cz, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: [PATCH] isofs: Prevent the use of too small fid Date: Fri, 4 Apr 2025 13:31:29 +0800 X-OQ-MSGID: <20250404053128.2801269-2-eadavis@qq.com> X-Mailer: git-send-email 2.49.0 In-Reply-To: <67eee51c.050a0220.9040b.0240.GAE@google.com> References: <67eee51c.050a0220.9040b.0240.GAE@google.com> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 syzbot reported a slab-out-of-bounds Read in isofs_fh_to_parent. [1] The handle_bytes value passed in by the reproducing program is equal to 12. In handle_to_path(), only 12 bytes of memory are allocated for the structure file_handle->f_handle member, which causes an out-of-bounds access when accessing the member parent_block of the structure isofs_fid in isofs, because accessing parent_block requires at least 16 bytes of f_handle. Here, fh_len is used to indirectly confirm that the value of handle_bytes is greater than 3 before accessing parent_block. [1] BUG: KASAN: slab-out-of-bounds in isofs_fh_to_parent+0x1b8/0x210 fs/isofs/export.c:183 Read of size 4 at addr ffff0000cc030d94 by task syz-executor215/6466 CPU: 1 UID: 0 PID: 6466 Comm: syz-executor215 Not tainted 6.14.0-rc7-syzkaller-ga2392f333575 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025 Call trace: show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:466 (C) __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0xe4/0x150 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:408 [inline] print_report+0x198/0x550 mm/kasan/report.c:521 kasan_report+0xd8/0x138 mm/kasan/report.c:634 __asan_report_load4_noabort+0x20/0x2c mm/kasan/report_generic.c:380 isofs_fh_to_parent+0x1b8/0x210 fs/isofs/export.c:183 exportfs_decode_fh_raw+0x2dc/0x608 fs/exportfs/expfs.c:523 do_handle_to_path+0xa0/0x198 fs/fhandle.c:257 handle_to_path fs/fhandle.c:385 [inline] do_handle_open+0x8cc/0xb8c fs/fhandle.c:403 __do_sys_open_by_handle_at fs/fhandle.c:443 [inline] __se_sys_open_by_handle_at fs/fhandle.c:434 [inline] __arm64_sys_open_by_handle_at+0x80/0x94 fs/fhandle.c:434 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 Allocated by task 6466: kasan_save_stack mm/kasan/common.c:47 [inline] kasan_save_track+0x40/0x78 mm/kasan/common.c:68 kasan_save_alloc_info+0x40/0x50 mm/kasan/generic.c:562 poison_kmalloc_redzone mm/kasan/common.c:377 [inline] __kasan_kmalloc+0xac/0xc4 mm/kasan/common.c:394 kasan_kmalloc include/linux/kasan.h:260 [inline] __do_kmalloc_node mm/slub.c:4294 [inline] __kmalloc_noprof+0x32c/0x54c mm/slub.c:4306 kmalloc_noprof include/linux/slab.h:905 [inline] handle_to_path fs/fhandle.c:357 [inline] do_handle_open+0x5a4/0xb8c fs/fhandle.c:403 __do_sys_open_by_handle_at fs/fhandle.c:443 [inline] __se_sys_open_by_handle_at fs/fhandle.c:434 [inline] __arm64_sys_open_by_handle_at+0x80/0x94 fs/fhandle.c:434 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline] invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49 el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151 el0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:744 el0t_64_sync_handler+0x84/0x108 arch/arm64/kernel/entry-common.c:762 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600 Reported-by: syzbot+4d7cd7dd0ce1aa8d5c65@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=4d7cd7dd0ce1aa8d5c65 Tested-by: syzbot+4d7cd7dd0ce1aa8d5c65@syzkaller.appspotmail.com Signed-off-by: Edward Adam Davis --- fs/isofs/export.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/isofs/export.c b/fs/isofs/export.c index 35768a63fb1d..421d247fae52 100644 --- a/fs/isofs/export.c +++ b/fs/isofs/export.c @@ -180,7 +180,7 @@ static struct dentry *isofs_fh_to_parent(struct super_block *sb, return NULL; return isofs_export_iget(sb, - fh_len > 2 ? ifid->parent_block : 0, + fh_len > 3 ? ifid->parent_block : 0, ifid->parent_offset, fh_len > 4 ? ifid->parent_generation : 0); }