Re: [PATCH 05/17] MIPS: bpf: Return error code if the offset is a negative number
From: Alexei Starovoitov <hidden>
Date: 2014-06-23 22:09:03
Also in:
linux-mips
On Mon, Jun 23, 2014 at 2:38 AM, Markos Chandras [off-list ref] wrote:
Previously, the negative offset was not checked leading to failures due to trying to load data beyond the skb struct boundaries. Until we have proper asm helpers in place, it's best if we return ENOSUPP if K is negative when trying to JIT the filter or 0 during runtime if we do an indirect load where the value of X is unknown during build time. Cc: "David S. Miller" <davem@davemloft.net> Cc: Daniel Borkmann <redacted> Cc: Alexei Starovoitov <redacted> Cc: netdev@vger.kernel.org Signed-off-by: Markos Chandras <redacted>
Hi Markos, thank you for addressing all of my earlier comments. Looks like test_bpf was quite useful in finding all of these bugs :) For the patches that reached netdev: Acked-by: Alexei Starovoitov <redacted> One minor nit below:
quoted hunk ↗ jump to hunk
--- arch/mips/net/bpf_jit.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)diff --git a/arch/mips/net/bpf_jit.c b/arch/mips/net/bpf_jit.c index 5cc92c4590cb..95728ea6cb74 100644 --- a/arch/mips/net/bpf_jit.c +++ b/arch/mips/net/bpf_jit.c@@ -331,6 +331,12 @@ static inline void emit_srl(unsigned int dst, unsigned int src, emit_instr(ctx, srl, dst, src, sa); } +static inline void emit_slt(unsigned int dst, unsigned int src1, + unsigned int src2, struct jit_ctx *ctx) +{ + emit_instr(ctx, slt, dst, src1, src2); +} + static inline void emit_sltu(unsigned int dst, unsigned int src1, unsigned int src2, struct jit_ctx *ctx) {@@ -816,8 +822,21 @@ static int build_body(struct jit_ctx *ctx) /* A <- P[k:1] */ load_order = 0; load: + /* the interpreter will deal with the negative K */ + if ((int)k < 0)
should be a space after cast.