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[23.128.96.18]) by mx.google.com with ESMTP id l16si156820edj.405.2021.05.10.04.29.55; Mon, 10 May 2021 04:30:19 -0700 (PDT) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@linuxfoundation.org header.s=korg header.b=J4yFiRMD; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linuxfoundation.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238931AbhEJLZ5 (ORCPT + 99 others); Mon, 10 May 2021 07:25:57 -0400 Received: from mail.kernel.org ([198.145.29.99]:53024 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234374AbhEJK4S (ORCPT ); Mon, 10 May 2021 06:56:18 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 1438361991; Mon, 10 May 2021 10:45:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1620643531; bh=ZZGZsIdjP6OhAwYWvSF6Lf7Z15yVex5kaPiyarkXG+s=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=J4yFiRMDWlkOVqNr1CxocgkddfDVN9yTEH79OSx3gjvAjY6cJsbSxzBARRs1fMpQm ZjSAwiecJllCJECsC2yGn1ipl/ISiHPz+erypZI8VaQH0XcfYZznepAXqLu1TP86YU BNX53sPW8tV6ayGcQqZOs7l7nkNSkFzK4zvmkHRw= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Disseldorp , Ronnie Sahlberg , "Paulo Alcantara (SUSE)" , Steve French Subject: [PATCH 5.11 051/342] cifs: fix leak in cifs_smb3_do_mount() ctx Date: Mon, 10 May 2021 12:17:21 +0200 Message-Id: <20210510102011.813416272@linuxfoundation.org> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20210510102010.096403571@linuxfoundation.org> References: <20210510102010.096403571@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: David Disseldorp commit 315db9a05b7a56810728589baa930864107e4634 upstream. cifs_smb3_do_mount() calls smb3_fs_context_dup() and then cifs_setup_volume_info(). The latter's subsequent smb3_parse_devname() call overwrites the cifs_sb->ctx->UNC string already dup'ed by smb3_fs_context_dup(), resulting in a leak. E.g. unreferenced object 0xffff888002980420 (size 32): comm "mount", pid 160, jiffies 4294892541 (age 30.416s) hex dump (first 32 bytes): 5c 5c 31 39 32 2e 31 36 38 2e 31 37 34 2e 31 30 \\192.168.174.10 34 5c 72 61 70 69 64 6f 2d 73 68 61 72 65 00 00 4\rapido-share.. backtrace: [<00000000069e12f6>] kstrdup+0x28/0x50 [<00000000b61f4032>] smb3_fs_context_dup+0x127/0x1d0 [cifs] [<00000000c6e3e3bf>] cifs_smb3_do_mount+0x77/0x660 [cifs] [<0000000063467a6b>] smb3_get_tree+0xdf/0x220 [cifs] [<00000000716f731e>] vfs_get_tree+0x1b/0x90 [<00000000491d3892>] path_mount+0x62a/0x910 [<0000000046b2e774>] do_mount+0x50/0x70 [<00000000ca7b64dd>] __x64_sys_mount+0x81/0xd0 [<00000000b5122496>] do_syscall_64+0x33/0x40 [<000000002dd397af>] entry_SYSCALL_64_after_hwframe+0x44/0xae This change is a bandaid until the cifs_setup_volume_info() TODO and error handling issues are resolved. Signed-off-by: David Disseldorp Acked-by: Ronnie Sahlberg Reviewed-by: Paulo Alcantara (SUSE) CC: # v5.11+ Signed-off-by: Steve French Signed-off-by: Greg Kroah-Hartman --- fs/cifs/cifsfs.c | 6 ++++++ 1 file changed, 6 insertions(+) --- a/fs/cifs/cifsfs.c +++ b/fs/cifs/cifsfs.c @@ -823,6 +823,12 @@ cifs_smb3_do_mount(struct file_system_ty goto out; } + /* cifs_setup_volume_info->smb3_parse_devname() redups UNC & prepath */ + kfree(cifs_sb->ctx->UNC); + cifs_sb->ctx->UNC = NULL; + kfree(cifs_sb->ctx->prepath); + cifs_sb->ctx->prepath = NULL; + rc = cifs_setup_volume_info(cifs_sb->ctx, NULL, old_ctx->UNC); if (rc) { root = ERR_PTR(rc);