| Message ID | 20170522140746.GA10113@embeddedgus |
|---|---|
| State | Rejected, archived |
| Delegated to: | David Miller |
| Headers | show |
From: "Gustavo A. R. Silva" <garsilva@embeddedor.com> Date: Mon, 22 May 2017 09:07:46 -0500 > Execution cannot reach NET_IP_ALIGN inside the following statement: > ip_align = strict ? 2 : NET_IP_ALIGN > > Addresses-Coverity-ID: 1409762 > Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> > --- > NOTE: variable ip_align could also be removed and use value 2 directly. Incorrect. Some platforms define NET_IP_ALIGN to zero, so the code must remain as is.
Hi David, Quoting David Miller <davem@davemloft.net>: > From: "Gustavo A. R. Silva" <garsilva@embeddedor.com> > Date: Mon, 22 May 2017 09:07:46 -0500 > >> Execution cannot reach NET_IP_ALIGN inside the following statement: >> ip_align = strict ? 2 : NET_IP_ALIGN >> >> Addresses-Coverity-ID: 1409762 >> Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> >> --- >> NOTE: variable ip_align could also be removed and use value 2 directly. > > Incorrect. > > Some platforms define NET_IP_ALIGN to zero, so the code must remain > as is. The following piece of code at kernel/bpf/verifier.c:798 is preventing value NET_IP_ALIGN to be stored in variable ip_align when _strict_ is false: 798 if (!strict || size == 1) 799 return 0; Thanks -- Gustavo A. R. Silva
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1eddb71..94f6e46 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -812,7 +812,7 @@ static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg, * we force this to 2 which is universally what architectures use * when they don't set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS. */ - ip_align = strict ? 2 : NET_IP_ALIGN; + ip_align = 2; if ((ip_align + reg_off + off) % size != 0) { verbose("misaligned packet access off %d+%d+%d size %d\n", ip_align, reg_off, off, size);
Execution cannot reach NET_IP_ALIGN inside the following statement: ip_align = strict ? 2 : NET_IP_ALIGN Addresses-Coverity-ID: 1409762 Signed-off-by: Gustavo A. R. Silva <garsilva@embeddedor.com> --- NOTE: variable ip_align could also be removed and use value 2 directly. kernel/bpf/verifier.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)