On Wed, Apr 24, 2019 at 11:00:18AM -0700, Zubin Mithra wrote:
From: Daniel Borkmann daniel@iogearbox.net
commit f7bd9e36ee4a4ce38e1cddd7effe6c0d9943285b upstream
Add a bpf_check_basics_ok() and reject filters that are of invalid size much earlier, so we don't do any useless work such as invoking bpf_prog_alloc(). Currently, rejection happens in bpf_check_classic() only, but it's really unnecessarily late and they should be rejected at earliest point. While at it, also clean up one bpf_prog_size() to make it consistent with the remaining invocations.
Signed-off-by: Daniel Borkmann daniel@iogearbox.net Acked-by: Alexei Starovoitov ast@kernel.org Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Zubin Mithra zsm@chromium.org
Notes:
- Syzkaller reported a kernel BUG related to a kernel paging request in bpf_prog_create with the following stacktrace when fuzzing a 4.4 kernel.
Call Trace: [<ffffffff822ac1c8>] bpf_prog_create+0xc8/0x210 net/core/filter.c:1067 [<ffffffff82454699>] bpf_mt_check+0xb9/0x120 net/netfilter/xt_bpf.c:31 [<ffffffff82437db8>] xt_check_match+0x238/0x730 net/netfilter/x_tables.c:409 [<ffffffff82940254>] ebt_check_match net/bridge/netfilter/ebtables.c:380 [inline] [<ffffffff82940254>] ebt_check_entry+0x844/0x1740 net/bridge/netfilter/ebtables.c:709 [<ffffffff82946842>] translate_table+0xcb2/0x1e80 net/bridge/netfilter/ebtables.c:946 [<ffffffff8294a918>] do_replace_finish+0x6e8/0x1fd0 net/bridge/netfilter/ebtables.c:1002 [<ffffffff8294c419>] do_replace+0x219/0x370 net/bridge/netfilter/ebtables.c:1145 [<ffffffff8294c649>] do_ebt_set_ctl+0xd9/0x110 net/bridge/netfilter/ebtables.c:1492 [<ffffffff8239a87c>] nf_sockopt net/netfilter/nf_sockopt.c:105 [inline] [<ffffffff8239a87c>] nf_setsockopt+0x6c/0xc0 net/netfilter/nf_sockopt.c:114 [<ffffffff825ddeb6>] ip_setsockopt+0xa6/0xc0 net/ipv4/ip_sockglue.c:1226 [<ffffffff825fd3c7>] tcp_setsockopt+0x87/0xd0 net/ipv4/tcp.c:2701 [<ffffffff8220343a>] sock_common_setsockopt+0x9a/0xe0 net/core/sock.c:2690 [<ffffffff822006ed>] SYSC_setsockopt net/socket.c:1767 [inline] [<ffffffff822006ed>] SyS_setsockopt+0x15d/0x240 net/socket.c:1746 [<ffffffff82a16f9b>] entry_SYSCALL_64_fastpath+0x18/0x94
- This patch resolves the following conflicts when applying to v4.4.y:
- __get_filter does not exist in v4.4. Instead the checks are moved into __sk_attach_filter.
This patch is present in v4.9.y.
Tests run: Chrome OS tryjobs, Syzkaller reproducer
Now queued up, thanks.
greg k-h