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| author | Alexei Starovoitov <ast@plumgrid.com> | 2015-04-15 00:57:13 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2015-04-16 18:06:11 +0200 |
| commit | c3de6317d748e23b9e46ba36e10483728d00d144 (patch) | |
| tree | f86a0a9e82ec37f89f4ed5261c000fb3889a13df /kernel/bpf | |
| parent | cxgb4: drop __GFP_NOFAIL allocation (diff) | |
| download | linux-c3de6317d748e23b9e46ba36e10483728d00d144.tar.xz linux-c3de6317d748e23b9e46ba36e10483728d00d144.zip | |
bpf: fix verifier memory corruption
Due to missing bounds check the DAG pass of the BPF verifier can corrupt
the memory which can cause random crashes during program loading:
[8.449451] BUG: unable to handle kernel paging request at ffffffffffffffff
[8.451293] IP: [<ffffffff811de33d>] kmem_cache_alloc_trace+0x8d/0x2f0
[8.452329] Oops: 0000 [#1] SMP
[8.452329] Call Trace:
[8.452329] [<ffffffff8116cc82>] bpf_check+0x852/0x2000
[8.452329] [<ffffffff8116b7e4>] bpf_prog_load+0x1e4/0x310
[8.452329] [<ffffffff811b190f>] ? might_fault+0x5f/0xb0
[8.452329] [<ffffffff8116c206>] SyS_bpf+0x806/0xa30
Fixes: f1bca824dabb ("bpf: add search pruning optimization to verifier")
Signed-off-by: Alexei Starovoitov <ast@plumgrid.com>
Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel/bpf')
| -rw-r--r-- | kernel/bpf/verifier.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 630a7bac1e51..66bec36ec1ec 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1397,7 +1397,8 @@ peek_stack: /* tell verifier to check for equivalent states * after every call and jump */ - env->explored_states[t + 1] = STATE_LIST_MARK; + if (t + 1 < insn_cnt) + env->explored_states[t + 1] = STATE_LIST_MARK; } else { /* conditional jump with two edges */ ret = push_insn(t, t + 1, FALLTHROUGH, env); |