bpf: fix verifier memory corruption
authorAlexei Starovoitov <ast@plumgrid.com>
Tue, 14 Apr 2015 22:57:13 +0000 (15:57 -0700)
committerDavid S. Miller <davem@davemloft.net>
Thu, 16 Apr 2015 16:06:11 +0000 (12:06 -0400)
commitc3de6317d748e23b9e46ba36e10483728d00d144
treef86a0a9e82ec37f89f4ed5261c000fb3889a13df
parentf72f116a2a70f616ea44f86775ae6404c84ea8ef
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>
kernel/bpf/verifier.c