Someone who is root or capable(CAP_SYS_ADMIN) could corrupt the
superblock and make Btrfs printk("%s") crash while holding the
uuid_mutex since nobody forces a limit on the string. Since the
uuid_mutex is significant, the system would be unusable
afterwards.
Signed-off-by: Stefan Behrens <sbehrens@xxxxxxxxxxxxxxxx>
---
fs/btrfs/volumes.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)
diff --git a/fs/btrfs/volumes.c b/fs/btrfs/volumes.c
index eeed97d..a429cc6 100644
--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -764,10 +764,13 @@ int btrfs_scan_one_device(const char *path, fmode_t flags, void *holder,
devid = btrfs_stack_device_id(&disk_super->dev_item);
transid = btrfs_super_generation(disk_super);
total_devices = btrfs_super_num_devices(disk_super);
- if (disk_super->label[0])
+ if (disk_super->label[0]) {
+ if (disk_super->label[BTRFS_LABEL_SIZE - 1])
+ disk_super->label[BTRFS_LABEL_SIZE - 1] = '\0';
printk(KERN_INFO "device label %s ", disk_super->label);
- else
+ } else {
printk(KERN_INFO "device fsid %pU ", disk_super->fsid);
+ }
printk(KERN_CONT "devid %llu transid %llu %s\n",
(unsigned long long)devid, (unsigned long long)transid, path);
ret = device_list_add(path, disk_super, devid, fs_devices_ret);
--
1.8.0
--
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