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authorAlexei Starovoitov <ast@plumgrid.com>2015-04-14 15:57:13 -0700
committerDavid S. Miller <davem@davemloft.net>2015-04-16 12:06:11 -0400
commitc3de6317d748e23b9e46ba36e10483728d00d144 (patch)
treef86a0a9e82ec37f89f4ed5261c000fb3889a13df /kernel
parentf72f116a2a70f616ea44f86775ae6404c84ea8ef (diff)
downloadlinux-c3de6317d748e23b9e46ba36e10483728d00d144.tar.gz
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')
-rw-r--r--kernel/bpf/verifier.c3
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);