| Message ID | e3fa964f-54f2-7310-59d1-41a4b7ad9a5b@solarflare.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
On 07/21/2017 03:37 PM, Edward Cree wrote: > We have to subtract the src max from the dst min, and vice-versa, since > (e.g.) the smallest result comes from the largest subtrahend. > > Fixes: 484611357c19 ("bpf: allow access into map value arrays") > Signed-off-by: Edward Cree <ecree@solarflare.com> LGTM, thanks for the fix! Acked-by: Daniel Borkmann <daniel@iogearbox.net> > --- > kernel/bpf/verifier.c | 21 +++++++++++++++------ > 1 file changed, 15 insertions(+), 6 deletions(-) > > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index af9e84a..664d939 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -1865,10 +1865,12 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, > * do our normal operations to the register, we need to set the values > * to the min/max since they are undefined. > */ > - if (min_val == BPF_REGISTER_MIN_RANGE) > - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; > - if (max_val == BPF_REGISTER_MAX_RANGE) > - dst_reg->max_value = BPF_REGISTER_MAX_RANGE; > + if (opcode != BPF_SUB) { > + if (min_val == BPF_REGISTER_MIN_RANGE) > + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; > + if (max_val == BPF_REGISTER_MAX_RANGE) > + dst_reg->max_value = BPF_REGISTER_MAX_RANGE; > + } > > switch (opcode) { > case BPF_ADD: > @@ -1879,10 +1881,17 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, > dst_reg->min_align = min(src_align, dst_align); > break; > case BPF_SUB: > + /* If one of our values was at the end of our ranges, then the > + * _opposite_ value in the dst_reg goes to the end of our range. > + */ > + if (min_val == BPF_REGISTER_MIN_RANGE) > + dst_reg->max_value = BPF_REGISTER_MAX_RANGE; > + if (max_val == BPF_REGISTER_MAX_RANGE) > + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; > if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) > - dst_reg->min_value -= min_val; > + dst_reg->min_value -= max_val; > if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) > - dst_reg->max_value -= max_val; > + dst_reg->max_value -= min_val; > dst_reg->min_align = min(src_align, dst_align); > break; > case BPF_MUL: >
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index af9e84a..664d939 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -1865,10 +1865,12 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, * do our normal operations to the register, we need to set the values * to the min/max since they are undefined. */ - if (min_val == BPF_REGISTER_MIN_RANGE) - dst_reg->min_value = BPF_REGISTER_MIN_RANGE; - if (max_val == BPF_REGISTER_MAX_RANGE) - dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + if (opcode != BPF_SUB) { + if (min_val == BPF_REGISTER_MIN_RANGE) + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; + if (max_val == BPF_REGISTER_MAX_RANGE) + dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + } switch (opcode) { case BPF_ADD: @@ -1879,10 +1881,17 @@ static void adjust_reg_min_max_vals(struct bpf_verifier_env *env, dst_reg->min_align = min(src_align, dst_align); break; case BPF_SUB: + /* If one of our values was at the end of our ranges, then the + * _opposite_ value in the dst_reg goes to the end of our range. + */ + if (min_val == BPF_REGISTER_MIN_RANGE) + dst_reg->max_value = BPF_REGISTER_MAX_RANGE; + if (max_val == BPF_REGISTER_MAX_RANGE) + dst_reg->min_value = BPF_REGISTER_MIN_RANGE; if (dst_reg->min_value != BPF_REGISTER_MIN_RANGE) - dst_reg->min_value -= min_val; + dst_reg->min_value -= max_val; if (dst_reg->max_value != BPF_REGISTER_MAX_RANGE) - dst_reg->max_value -= max_val; + dst_reg->max_value -= min_val; dst_reg->min_align = min(src_align, dst_align); break; case BPF_MUL:
We have to subtract the src max from the dst min, and vice-versa, since (e.g.) the smallest result comes from the largest subtrahend. Fixes: 484611357c19 ("bpf: allow access into map value arrays") Signed-off-by: Edward Cree <ecree@solarflare.com> --- kernel/bpf/verifier.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-)