diff options
| author | Rabin Vincent <rabin@rab.in> | 2016-01-05 16:23:07 +0100 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2016-01-31 11:23:36 -0800 |
| commit | 5596242a6263ece70ee14f3b6861f02b8dc82d11 (patch) | |
| tree | 72a12bd35b834cebd31fa8d1cc428a7279bab74d /arch/mips | |
| parent | a6b1d24893805bb4f2e7c7bc6f86a98ec37065ee (diff) | |
net: filter: make JITs zero A for SKF_AD_ALU_XOR_X
[ Upstream commit 55795ef5469290f89f04e12e662ded604909e462 ]
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch/mips')
| -rw-r--r-- | arch/mips/net/bpf_jit.c | 16 |
1 files changed, 1 insertions, 15 deletions
diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c index e23fdf2a9c80..d6d27d51d131 100644 --- a/arch/mips/net/bpf_jit.c +++ b/arch/mips/net/bpf_jit.c @@ -556,19 +556,6 @@ static inline u16 align_sp(unsigned int num) return num; } -static bool is_load_to_a(u16 inst) -{ - switch (inst) { - 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: - return true; - default: - return false; - } -} - static void save_bpf_jit_regs(struct jit_ctx *ctx, unsigned offset) { int i = 0, real_off = 0; @@ -686,7 +673,6 @@ static unsigned int get_stack_depth(struct jit_ctx *ctx) static void build_prologue(struct jit_ctx *ctx) { - u16 first_inst = ctx->skf->insns[0].code; int sp_off; /* Calculate the total offset for the stack pointer */ @@ -700,7 +686,7 @@ static void build_prologue(struct jit_ctx *ctx) emit_jit_reg_move(r_X, r_zero, ctx); /* Do not leak kernel data to userspace */ - if ((first_inst != (BPF_RET | BPF_K)) && !(is_load_to_a(first_inst))) + if (bpf_needs_clear_a(&ctx->skf->insns[0])) emit_jit_reg_move(r_A, r_zero, ctx); } |