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| author | David Sterba <dsterba@suse.com> | 2023-01-24 20:32:10 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-03-03 11:52:21 +0100 |
| commit | 07c5877e14441f259177a77c48535661a8eb8358 (patch) | |
| tree | 50eb9cdfbf7cf9e25ab0ca5feb901533a153c0bd | |
| parent | 91210aca68f32c9c81587fbb711ff40ff11a144f (diff) | |
| download | linux-riscv-07c5877e14441f259177a77c48535661a8eb8358.tar.gz linux-riscv-07c5877e14441f259177a77c48535661a8eb8358.tar.bz2 linux-riscv-07c5877e14441f259177a77c48535661a8eb8358.zip | |
btrfs: send: limit number of clones and allocated memory size
[ Upstream commit 33e17b3f5ab74af12aca58c515bc8424ff69a343 ]
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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
| -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 1c4b693ee4a3..937b60ae576e 100644 --- a/fs/btrfs/send.c +++ b/fs/btrfs/send.c @@ -7839,10 +7839,10 @@ 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; } |