linux

iv/linux

History

Daniel Borkmann ef0915cacd bpf: fix loading of BPF_MAXINSNS sized programs

General assumption is that single program can hold up to BPF_MAXINSNS,
that is, 4096 number of instructions. It is the case with cBPF and
that limit was carried over to eBPF. When recently testing digest, I
noticed that it's actually not possible to feed 4096 instructions
via bpf(2).

The check for > BPF_MAXINSNS was added back then to bpf_check() in
cbd357008604 ("bpf: verifier (add ability to receive verification log)").
However, 09756af46893 ("bpf: expand BPF syscall with program load/unload")
added yet another check that comes before that into bpf_prog_load(),
but this time bails out already in case of >= BPF_MAXINSNS.

Fix it up and perform the check early in bpf_prog_load(), so we can drop
the second one in bpf_check(). It makes sense, because also a 0 insn
program is useless and we don't want to waste any resources doing work
up to bpf_check() point. The existing bpf(2) man page documents E2BIG
as the official error for such cases, so just stick with it as well.

Fixes: 09756af46893 ("bpf: expand BPF syscall with program load/unload")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

2016-12-07 13:16:04 -05:00

arraymap.c

bpf: Add bpf_current_task_under_cgroup helper

2016-08-12 21:49:41 -07:00

bpf_lru_list.c

bpf: Fix compilation warning in __bpf_lru_list_rotate_inactive

2016-11-16 11:30:56 -05:00

bpf_lru_list.h

bpf: Add percpu LRU list

2016-11-15 11:50:20 -05:00

cgroup.c

bpf: Add new cgroup attach type to enable sock modifications