diff options
| author | Rabin Vincent <rabin@rab.in> | 2016-01-05 18:23:07 +0300 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2016-01-06 08:43:52 +0300 |
| commit | 55795ef5469290f89f04e12e662ded604909e462 (patch) | |
| tree | df413e913330af821e7989534a4d36ea621bab56 /arch/powerpc/net/bpf_jit_comp.c | |
| parent | ff62198553e43cdffa9d539f6165d3e83f8a42bc (diff) | |
| download | linux-55795ef5469290f89f04e12e662ded604909e462.tar.xz | |
net: filter: make JITs zero A for SKF_AD_ALU_XOR_X
The SKF_AD_ALU_XOR_X ancillary is not like the other ancillary data
instructions since it XORs A with X while all the others replace A with
some loaded value. All the BPF JITs fail to clear A if this is used as
the first instruction in a filter. This was found using american fuzzy
lop.
Add a helper to determine if A needs to be cleared given the first
instruction in a filter, and use this in the JITs. Except for ARM, the
rest have only been compile-tested.
Fixes: 3480593131e0 ("net: filter: get rid of BPF_S_* enum")
Signed-off-by: Rabin Vincent <rabin@rab.in>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'arch/powerpc/net/bpf_jit_comp.c')
| -rw-r--r-- | arch/powerpc/net/bpf_jit_comp.c | 13 |
1 files changed, 2 insertions, 11 deletions
diff --git a/arch/powerpc/net/bpf_jit_comp.c b/arch/powerpc/net/bpf_jit_comp.c index 04782164ee67..2d66a8446198 100644 --- a/arch/powerpc/net/bpf_jit_comp.c +++ b/arch/powerpc/net/bpf_jit_comp.c @@ -78,18 +78,9 @@ static void bpf_jit_build_prologue(struct bpf_prog *fp, u32 *image, PPC_LI(r_X, 0); } - switch (filter[0].code) { - case BPF_RET | BPF_K: - case BPF_LD | BPF_W | BPF_LEN: - case BPF_LD | BPF_W | BPF_ABS: - case BPF_LD | BPF_H | BPF_ABS: - case BPF_LD | BPF_B | BPF_ABS: - /* first instruction sets A register (or is RET 'constant') */ - break; - default: - /* make sure we dont leak kernel information to user */ + /* make sure we dont leak kernel information to user */ + if (bpf_needs_clear_a(&filter[0])) PPC_LI(r_A, 0); - } } static void bpf_jit_build_epilogue(u32 *image, struct codegen_context *ctx) |