From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from cn.fujitsu.com ([59.151.112.132]:13782 "EHLO heian.cn.fujitsu.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751510AbbAFJar (ORCPT ); Tue, 6 Jan 2015 04:30:47 -0500 Received: from G08CNEXCHPEKD02.g08.fujitsu.local (localhost.localdomain [127.0.0.1]) by edo.cn.fujitsu.com (8.14.3/8.13.1) with ESMTP id t069UDBg016362 for ; Tue, 6 Jan 2015 17:30:13 +0800 From: Qu Wenruo To: Subject: [PATCH v2] btrfs-progs: Fix a buffer overflow causing segfault in fstests/btrfs/069 Date: Tue, 6 Jan 2015 17:30:44 +0800 Message-ID: <1420536644-12152-1-git-send-email-quwenruo@cn.fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain Sender: linux-btrfs-owner@vger.kernel.org List-ID: The newly introduced search_chunk_tree_for_fs_info() won't count devid 0 in fi_arg->num_devices, which will cause buffer overflow since later get_device_info() will fill di_args with devid. This can be trigger by fstests/btrfs/069 and any operations needs to iterate over all the devices like 'fi show' or 'dev stat' while replacing. The fix is do an extra probe specifically for devid 0 after search_chunk_tree_for_fs_info() and change num_devices if needed. Reported-by: Tsutomu Itoh Signed-off-by: Qu Wenruo Signed-off-by: Gui Hecheng --- utils.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/utils.c b/utils.c index af0a8fe..6581568 100644 --- a/utils.c +++ b/utils.c @@ -1934,8 +1934,10 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args, int ret = 0; int ndevs = 0; int i = 0; + int replacing = 0; struct btrfs_fs_devices *fs_devices_mnt = NULL; struct btrfs_ioctl_dev_info_args *di_args; + struct btrfs_ioctl_dev_info_args tmp; char mp[BTRFS_PATH_NAME_MAX + 1]; DIR *dirstream = NULL; @@ -2003,6 +2005,19 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args, ret = search_chunk_tree_for_fs_info(fd, fi_args); if (ret) goto out; + + /* + * search_chunk_tree_for_fs_info() will lacks the devid 0 + * so manual probe for it here. + */ + ret = get_device_info(fd, 0, &tmp); + if (!ret) { + fi_args->num_devices++; + ndevs++; + replacing = 1; + if (i == 0) + i++; + } } if (!fi_args->num_devices) @@ -2014,6 +2029,8 @@ int get_fs_info(char *path, struct btrfs_ioctl_fs_info_args *fi_args, goto out; } + if (replacing) + memcpy(di_args, &tmp, sizeof(tmp)); for (; i <= fi_args->max_id; ++i) { ret = get_device_info(fd, i, &di_args[ndevs]); if (ret == -ENODEV) -- 2.2.1