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authorRabin Vincent <rabin@rab.in>2016-01-05 16:23:07 +0100
committerDavid S. Miller <davem@davemloft.net>2016-01-06 00:43:52 -0500
commit55795ef5469290f89f04e12e662ded604909e462 (patch)
treedf413e913330af821e7989534a4d36ea621bab56 /arch/sparc/net
parentbridge: Only call /sbin/bridge-stp for the initial network namespace (diff)
downloadlinux-dev-55795ef5469290f89f04e12e662ded604909e462.tar.xz
linux-dev-55795ef5469290f89f04e12e662ded604909e462.zip
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/sparc/net')
-rw-r--r--arch/sparc/net/bpf_jit_comp.c17
1 files changed, 2 insertions, 15 deletions
diff --git a/arch/sparc/net/bpf_jit_comp.c b/arch/sparc/net/bpf_jit_comp.c
index 22564f5f2364..3e6e05a7c4c2 100644
--- a/arch/sparc/net/bpf_jit_comp.c
+++ b/arch/sparc/net/bpf_jit_comp.c
@@ -420,22 +420,9 @@ void bpf_jit_compile(struct bpf_prog *fp)
}
emit_reg_move(O7, r_saved_O7);
- 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:
- /* The first instruction sets the A register (or is
- * a "RET 'constant'")
- */
- break;
- default:
- /* Make sure we dont leak kernel information to the
- * user.
- */
+ /* Make sure we dont leak kernel information to the user. */
+ if (bpf_needs_clear_a(&filter[0]))
emit_clear(r_A); /* A = 0 */
- }
for (i = 0; i < flen; i++) {
unsigned int K = filter[i].k;