diff options
| author | David Sterba | 2023-01-24 20:32:10 +0100 |
|---|---|---|
| committer | David Sterba | 2023-01-27 14:57:05 +0100 |
| commit | 33e17b3f5ab74af12aca58c515bc8424ff69a343 (patch) | |
| tree | 90cbfd5d60eeabb66ea37bbc9ccb10e5eae62846 /fs | |
| parent | eadd7deca0ad8a83edb2b894d8326c78e78635d6 (diff) | |
btrfs: send: limit number of clones and allocated memory size
The arg->clone_sources_count is u64 and can trigger a warning when a
huge value is passed from user space and a huge array is allocated.
Limit the allocated memory to 8MiB (can be increased if needed), which
in turn limits the number of clone sources to 8M / sizeof(struct
clone_root) = 8M / 40 = 209715. Real world number of clones is from
tens to hundreds, so this is future proof.
Reported-by: syzbot+4376a9a073770c173269@syzkaller.appspotmail.com
Signed-off-by: David Sterba <dsterba@suse.com>
Diffstat (limited to 'fs')
| -rw-r--r-- | fs/btrfs/send.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/fs/btrfs/send.c b/fs/btrfs/send.c index 67f7c698ade3..26dace7b74c6 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -8072,10 +8072,10 @@ long btrfs_ioctl_send(struct inode *inode, struct btrfs_ioctl_send_args *arg) /* * Check that we don't overflow at later allocations, we request * clone_sources_count + 1 items, and compare to unsigned long inside - * access_ok. + * access_ok. Also set an upper limit for allocation size so this can't + * easily exhaust memory. Max number of clone sources is about 200K. */ - if (arg->clone_sources_count > - ULONG_MAX / sizeof(struct clone_root) - 1) { + if (arg->clone_sources_count > SZ_8M / sizeof(struct clone_root)) { ret = -EINVAL; goto out; } |