[nft PATCH v3] evaluate: fix a crash if we specify ether type or meta nfproto in reject

[Alvaro Neira Ayuso]

If we use this rule:

nft add rule bridge filter input \
ether type ip reject with icmp type host-unreachable

or that:

nft add rule inet filter input \
meta nfproto ipv4 reject with icmp type host-unreachable

we have a segfault because we add a network dependency when we already have
network context.

Signed-off-by: Alvaro Neira Ayuso <***@gmail.com>
---
src/evaluate.c | 14 +++++++-------
1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/evaluate.c b/src/evaluate.c
index d61d76b..1fec120 100644
--- a/src/evaluate.c
+++ b/src/evaluate.c
@@ -1142,7 +1142,7 @@ static int reject_payload_gen_dependency_tcp(struct eval_ctx *ctx,
return 0;
*payload = payload_expr_alloc(&stmt->location, &proto_tcp,
TCPHDR_UNSPEC);
- return 0;
+ return 1;
}

static int reject_payload_gen_dependency_family(struct eval_ctx *ctx,
@@ -1171,7 +1171,7 @@ static int reject_payload_gen_dependency_family(struct eval_ctx *ctx,
default:
BUG("unknown reject family");
}
- return 0;
+ return 1;
}

static int stmt_reject_gen_dependency(struct eval_ctx *ctx, struct stmt *stmt,
@@ -1179,21 +1179,21 @@ static int stmt_reject_gen_dependency(struct eval_ctx *ctx, struct stmt *stmt,
{
struct expr *payload = NULL;
struct stmt *nstmt;
+ int ret;

switch (stmt->reject.type) {
case NFT_REJECT_TCP_RST:
- if (reject_payload_gen_dependency_tcp(ctx, stmt, &payload) < 0)
- return -1;
+ ret = reject_payload_gen_dependency_tcp(ctx, stmt, &payload);
break;
case NFT_REJECT_ICMP_UNREACH:
- if (reject_payload_gen_dependency_family(ctx, stmt,
- &payload) < 0)
- return -1;
+ ret = reject_payload_gen_dependency_family(ctx, stmt, &payload);
break;
default:
BUG("cannot generate reject dependency for type %d",
stmt->reject.type);
}
+ if (ret <= 0)
+ return ret;

if (payload_gen_dependency(ctx, payload, &nstmt) < 0)
return -1;

[Pablo Neira Ayuso]

Post by Alvaro Neira Ayuso
nft add rule bridge filter input \
ether type ip reject with icmp type host-unreachable
nft add rule inet filter input \
meta nfproto ipv4 reject with icmp type host-unreachable
we have a segfault because we add a network dependency when we already have
network context.

Applied, thanks.
--
To unsubscribe from this list: send the line "unsubscribe netfilter-devel" in
the body of a message to ***@vger.kernel.org
More majordomo info at http://vger.kernel.org/majordomo-info.html