From dbed21e7c20d3f85d6edffe7cd25353af0569278 Mon Sep 17 00:00:00 2001 From: Qu Wenruo Date: Tue, 6 Jan 2015 17:30:44 +0800 Subject: btrfs-progs: Fix a buffer overflow causing segfault in fstests/btrfs/069 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 Signed-off-by: David Sterba --- utils.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/utils.c b/utils.c index 868b15e4..9b08144f 100644 --- a/utils.c +++ b/utils.c @@ -1943,8 +1943,10 @@ 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; @@ -2012,6 +2014,19 @@ 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) @@ -2023,6 +2038,8 @@ 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) -- cgit v1.2.3