payload: fix crash with uncombinable protocols

The dependency of non-combinable protocols (f.i. arp + tcp) results in
a relational dependency expression without a datatype, causing a segfault
later on.

Signed-off-by: Patrick McHardy <kaber@trash.net>

diff --git a/src/payload.c b/src/payload.c
index 003d84b8c75d42d856e1ddf6cb6ddd426546a007..611697ec064fd76d94e0316a4d60894943e980dc 100644 (file)
--- a/src/payload.c
+++ b/src/payload.c
@@ -141,8 +141,8 @@ payload_select_proto(const struct payload_desc *base, unsigned int num)
  * @base:      lower layer protocol description
  * @desc:      upper layer protocol description
  */
-static unsigned int payload_proto_val(const struct payload_desc *base,
-                                     const struct payload_desc *desc)
+static int payload_proto_val(const struct payload_desc *base,
+                            const struct payload_desc *desc)
 {
        unsigned int i;
 
@@ -150,7 +150,7 @@ static unsigned int payload_proto_val(const struct payload_desc *base,
                if (base->protocols[i].desc == desc)
                        return base->protocols[i].num;
        }
-       return 0;
+       return -1;
 }
 
 static const struct dev_payload_desc dev_payload_desc[] = {
@@ -297,7 +297,7 @@ int payload_gen_dependency(struct eval_ctx *ctx, const struct expr *expr,
        const struct payload_desc *desc;
        const struct payload_template *tmpl;
        struct expr *dep, *left, *right;
-       unsigned int protocol;
+       int protocol;
        uint16_t type;
 
        if (expr->payload.base < h->base) {
@@ -328,9 +328,14 @@ int payload_gen_dependency(struct eval_ctx *ctx, const struct expr *expr,
                                  "no %s protocol specified",
                                  payload_base_names[expr->payload.base - 1]);
 
+       protocol = payload_proto_val(desc, expr->payload.desc);
+       if (protocol < 0)
+               return expr_error(ctx, expr,
+                                 "conflicting protocols specified: %s vs. %s",
+                                 desc->name, expr->payload.desc->name);
+
        tmpl = &desc->templates[desc->protocol_key];
        left = payload_expr_alloc(&expr->location, desc, desc->protocol_key);
-       protocol = payload_proto_val(desc, expr->payload.desc);
        right = constant_expr_alloc(&expr->location, tmpl->dtype,
                                    BYTEORDER_HOST_ENDIAN,
                                    tmpl->len, &protocol);