From 75d6ad382bb91f363452119d34238e156589ca2d Mon Sep 17 00:00:00 2001 From: David Sterba Date: Fri, 31 Oct 2014 17:18:08 +0100 Subject: [PATCH] btrfs: more superblock checks, lower bounds on devices and sectorsize/nodesize I received a few crafted images from Jiri, all got through the recently added superblock checks. The lower bounds checks for num_devices and sector/node -sizes were missing and caused a crash during mount. Tools for symbolic code execution were used to prepare the images contents. Reported-by: Jiri Slaby Signed-off-by: David Sterba Signed-off-by: Chris Mason --- fs/btrfs/disk-io.c | 19 +++++++++++++++++++ 1 file changed, 19 insertions(+) diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index 612d46eece62..11171362bd33 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -3871,6 +3871,21 @@ static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info, printk(KERN_WARNING "BTRFS: log_root block unaligned: %llu\n", btrfs_super_log_root(sb)); + /* + * Check the lower bound, the alignment and other constraints are + * checked later. + */ + if (btrfs_super_nodesize(sb) < 4096) { + printk(KERN_ERR "BTRFS: nodesize too small: %u < 4096\n", + btrfs_super_nodesize(sb)); + ret = -EINVAL; + } + if (btrfs_super_sectorsize(sb) < 4096) { + printk(KERN_ERR "BTRFS: sectorsize too small: %u < 4096\n", + btrfs_super_sectorsize(sb)); + ret = -EINVAL; + } + if (memcmp(fs_info->fsid, sb->dev_item.fsid, BTRFS_UUID_SIZE) != 0) { printk(KERN_ERR "BTRFS: dev_item UUID does not match fsid: %pU != %pU\n", fs_info->fsid, sb->dev_item.fsid); @@ -3884,6 +3899,10 @@ static int btrfs_check_super_valid(struct btrfs_fs_info *fs_info, if (btrfs_super_num_devices(sb) > (1UL << 31)) printk(KERN_WARNING "BTRFS: suspicious number of devices: %llu\n", btrfs_super_num_devices(sb)); + if (btrfs_super_num_devices(sb) == 0) { + printk(KERN_ERR "BTRFS: number of devices is 0\n"); + ret = -EINVAL; + } if (btrfs_super_bytenr(sb) != BTRFS_SUPER_INFO_OFFSET) { printk(KERN_ERR "BTRFS: super offset mismatch %llu != %u\n", -- 2.20.1