Messages in this thread | | | Subject | Re: [PATCH v2 bpf-next] bpf: Fix latent unsoundness in and/or/xor value tracking | From | Daniel Borkmann <> | Date | Wed, 3 Apr 2024 10:39:20 +0200 |
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On 4/2/24 11:20 PM, Harishankar Vishwanathan wrote: [...] > diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c > index fcb62300f407..a7404a7d690f 100644 > --- a/kernel/bpf/verifier.c > +++ b/kernel/bpf/verifier.c > @@ -13326,23 +13326,21 @@ static void scalar32_min_max_and(struct bpf_reg_state *dst_reg, > return; > } > > - /* We get our minimum from the var_off, since that's inherently > + /* We get our minimum from the var32_off, since that's inherently > * bitwise. Our maximum is the minimum of the operands' maxima. > */ > dst_reg->u32_min_value = var32_off.value; > dst_reg->u32_max_value = min(dst_reg->u32_max_value, umax_val); > - if (dst_reg->s32_min_value < 0 || smin_val < 0) {
The smin_val is now unused, triggering the following warnings :
./kernel/bpf/verifier.c:13321:6: warning: unused variable 'smin_val' [-Wunused-variable] 13321 | s32 smin_val = src_reg->s32_min_value; | ^~~~~~~~ ./kernel/bpf/verifier.c:13352:6: warning: unused variable 'smin_val' [-Wunused-variable] 13352 | s64 smin_val = src_reg->smin_value; | ^~~~~~~~ ./kernel/bpf/verifier.c:13386:6: warning: unused variable 'smin_val' [-Wunused-variable] 13386 | s32 smin_val = src_reg->s32_min_value; | ^~~~~~~~ ./kernel/bpf/verifier.c:13417:6: warning: unused variable 'smin_val' [-Wunused-variable] 13417 | s64 smin_val = src_reg->smin_value; | ^~~~~~~~ ./kernel/bpf/verifier.c:13451:6: warning: unused variable 'smin_val' [-Wunused-variable] 13451 | s32 smin_val = src_reg->s32_min_value; | ^~~~~~~~ ./kernel/bpf/verifier.c:13479:6: warning: unused variable 'smin_val' [-Wunused-variable] 13479 | s64 smin_val = src_reg->smin_value; | ^~~~~~~~
Removing these builds fine then, please follow-up with a v3.
Thanks, Daniel
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