From patchwork Sat Oct 10 18:25:54 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vladimir Zapolskiy X-Patchwork-Id: 11830463 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF6E8C43467 for ; Sat, 10 Oct 2020 23:09:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BEDFC2075E for ; Sat, 10 Oct 2020 23:09:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388235AbgJJW4r (ORCPT ); Sat, 10 Oct 2020 18:56:47 -0400 Received: from mleia.com ([178.79.152.223]:55600 "EHLO mail.mleia.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731229AbgJJTEg (ORCPT ); Sat, 10 Oct 2020 15:04:36 -0400 X-Greylist: delayed 1309 seconds by postgrey-1.27 at vger.kernel.org; Sat, 10 Oct 2020 15:04:36 EDT Received: from mail.mleia.com (localhost [127.0.0.1]) by mail.mleia.com (Postfix) with ESMTP id B629E40FFF7; Sat, 10 Oct 2020 18:26:05 +0000 (UTC) From: Vladimir Zapolskiy To: Steve French Cc: Ronnie Sahlberg , linux-cifs@vger.kernel.org, Vladimir Zapolskiy Subject: [PATCH] cifs: Fix incomplete memory allocation on setxattr path Date: Sat, 10 Oct 2020 21:25:54 +0300 Message-Id: <20201010182554.337097-1-vz@mleia.com> X-Mailer: git-send-email 2.24.0 MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-49551924 X-CRM114-CacheID: sfid-20201010_182605_767711_67D155C6 X-CRM114-Status: GOOD ( 16.92 ) Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org From: Vladimir Zapolskiy On setxattr() syscall path due to an apprent typo the size of a dynamically allocated memory chunk for storing struct smb2_file_full_ea_info object is computed incorrectly, to be more precise the first addend is the size of a pointer instead of the wanted object size. Coincidentally it makes no difference on 64-bit platforms, however on 32-bit targets the following memcpy() writes 4 bytes of data outside of the dynamically allocated memory. ============================================================================= BUG kmalloc-16 (Not tainted): Redzone overwritten ----------------------------------------------------------------------------- Disabling lock debugging due to kernel taint INFO: 0x79e69a6f-0x9e5cdecf @offset=368. First byte 0x73 instead of 0xcc INFO: Slab 0xd36d2454 objects=85 used=51 fp=0xf7d0fc7a flags=0x35000201 INFO: Object 0x6f171df3 @offset=352 fp=0x00000000 Redzone 5d4ff02d: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc ................ Object 6f171df3: 00 00 00 00 00 05 06 00 73 6e 72 75 62 00 66 69 ........snrub.fi Redzone 79e69a6f: 73 68 32 0a sh2. Padding 56254d82: 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZ CPU: 0 PID: 8196 Comm: attr Tainted: G B 5.9.0-rc8+ #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1 04/01/2014 Call Trace: dump_stack+0x54/0x6e print_trailer+0x12c/0x134 check_bytes_and_report.cold+0x3e/0x69 check_object+0x18c/0x250 free_debug_processing+0xfe/0x230 __slab_free+0x1c0/0x300 kfree+0x1d3/0x220 smb2_set_ea+0x27d/0x540 cifs_xattr_set+0x57f/0x620 __vfs_setxattr+0x4e/0x60 __vfs_setxattr_noperm+0x4e/0x100 __vfs_setxattr_locked+0xae/0xd0 vfs_setxattr+0x4e/0xe0 setxattr+0x12c/0x1a0 path_setxattr+0xa4/0xc0 __ia32_sys_lsetxattr+0x1d/0x20 __do_fast_syscall_32+0x40/0x70 do_fast_syscall_32+0x29/0x60 do_SYSENTER_32+0x15/0x20 entry_SYSENTER_32+0x9f/0xf2 Fixes: 5517554e4313 ("cifs: Add support for writing attributes on SMB2+") Signed-off-by: Vladimir Zapolskiy Reviewed-by: Aurelien Aptel --- fs/cifs/smb2ops.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c index 24f107f763f0..76d82a60a550 100644 --- a/fs/cifs/smb2ops.c +++ b/fs/cifs/smb2ops.c @@ -1216,7 +1216,7 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon, rqst[1].rq_iov = si_iov; rqst[1].rq_nvec = 1; - len = sizeof(ea) + ea_name_len + ea_value_len + 1; + len = sizeof(*ea) + ea_name_len + ea_value_len + 1; ea = kzalloc(len, GFP_KERNEL); if (ea == NULL) { rc = -ENOMEM;