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| author | David S. Miller <davem@davemloft.net> | 2017-05-22 12:27:07 -0400 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-05-22 12:27:07 -0400 |
| commit | e4eda884db7930cee434828759064b4711604078 (patch) | |
| tree | b4a5875c74a19036e863ac1be67fab65fbd28c09 /kernel | |
| parent | 751da2a69b7cc82d83dc310ed7606225f2d6e014 (diff) | |
| download | linux-0-day-e4eda884db7930cee434828759064b4711604078.tar.gz linux-0-day-e4eda884db7930cee434828759064b4711604078.tar.xz | |
net: Make IP alignment calulations clearer.
The assignmnet:
ip_align = strict ? 2 : NET_IP_ALIGN;
in compare_pkt_ptr_alignment() trips up Coverity because we can only
get to this code when strict is true, therefore ip_align will always
be 2 regardless of NET_IP_ALIGN's value.
So just assign directly to '2' and explain the situation in the
comment above.
Reported-by: "Gustavo A. R. Silva" <garsilva@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/bpf/verifier.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 1eddb713b815c..c72cd41f5b8b9 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -808,11 +808,15 @@ static int check_pkt_ptr_alignment(const struct bpf_reg_state *reg, reg_off += reg->aux_off; } - /* skb->data is NET_IP_ALIGN-ed, but for strict alignment checking - * we force this to 2 which is universally what architectures use - * when they don't set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS. + /* For platforms that do not have a Kconfig enabling + * CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS the value of + * NET_IP_ALIGN is universally set to '2'. And on platforms + * that do set CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS, we get + * to this code only in strict mode where we want to emulate + * the NET_IP_ALIGN==2 checking. Therefore use an + * unconditional IP align value of '2'. */ - 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); |