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netfilter: nft_payload: cancel register tracking after payload update

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The payload expression might mangle the packet, cancel register tracking
since any payload data in the registers is stale.

Finer grain register tracking cancellation by inspecting the payload
base, offset and length on the register is also possible.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
This commit is contained in:
Pablo Neira Ayuso 2022-01-09 17:11:25 +01:00
parent be5650f8f4
commit cc003c7ee6
1 changed files with 21 additions and 0 deletions
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21
net/netfilter/nft_payload.c
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@ -798,12 +798,33 @@ nla_put_failure:
return -1;
}
static bool nft_payload_set_reduce(struct nft_regs_track *track,
const struct nft_expr *expr)
{
int i;
for (i = 0; i < NFT_REG32_NUM; i++) {
if (!track->regs[i].selector)
continue;
if (track->regs[i].selector->ops != &nft_payload_ops &&
track->regs[i].selector->ops != &nft_payload_fast_ops)
continue;
track->regs[i].selector = NULL;
track->regs[i].bitwise = NULL;
}
return false;
}
static const struct nft_expr_ops nft_payload_set_ops = {
.type = &nft_payload_type,
.size = NFT_EXPR_SIZE(sizeof(struct nft_payload_set)),
.eval = nft_payload_set_eval,
.init = nft_payload_set_init,
.dump = nft_payload_set_dump,
.reduce = nft_payload_set_reduce,
};
static const struct nft_expr_ops *