| Message ID | 1403516340-22997-6-git-send-email-markos.chandras@imgtec.com |
|---|---|
| State | Changes Requested, archived |
| Delegated to: | David Miller |
| Headers | show |
On Mon, Jun 23, 2014 at 2:38 AM, Markos Chandras <markos.chandras@imgtec.com> 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 <dborkman@redhat.com> > Cc: Alexei Starovoitov <ast@plumgrid.com> > Cc: netdev@vger.kernel.org > Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> 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 <ast@plumgrid.com> One minor nit below: > --- > 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. -- To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On 06/23/2014 11:09 PM, Alexei Starovoitov wrote: > On Mon, Jun 23, 2014 at 2:38 AM, Markos Chandras > <markos.chandras@imgtec.com> 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 <dborkman@redhat.com> >> Cc: Alexei Starovoitov <ast@plumgrid.com> >> Cc: netdev@vger.kernel.org >> Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> > > 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 <ast@plumgrid.com> > Thank you for the review and your constructive comments in your previous emails.
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) + return -ENOTSUPP; + emit_load_imm(r_off, k, ctx); load_common: + /* + * We may got here from the indirect loads so + * return if offset is negative. + */ + emit_slt(r_s0, r_off, r_zero, ctx); + emit_bcond(MIPS_COND_NE, r_s0, r_zero, + b_imm(prog->len, ctx), ctx); + emit_reg_move(r_ret, r_zero, ctx); + ctx->flags |= SEEN_CALL | SEEN_OFF | SEEN_S0 | SEEN_SKB | SEEN_A; @@ -880,6 +899,10 @@ load_ind: emit_load(r_X, r_skb, off, ctx); break; case BPF_LDX | BPF_B | BPF_MSH: + /* the interpreter will deal with the negative K */ + if ((int)k < 0) + return -ENOTSUPP; + /* X <- 4 * (P[k:1] & 0xf) */ ctx->flags |= SEEN_X | SEEN_CALL | SEEN_S0 | SEEN_SKB; /* Load offset to a1 */
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 <dborkman@redhat.com> Cc: Alexei Starovoitov <ast@plumgrid.com> Cc: netdev@vger.kernel.org Signed-off-by: Markos Chandras <markos.chandras@imgtec.com> --- arch/mips/net/bpf_jit.c | 23 +++++++++++++++++++++++ 1 file changed, 23 insertions(+)