path: root/src/payload.c
diff options
authorPhil Sutter <>2017-12-09 16:52:29 +0100
committerFlorian Westphal <>2017-12-12 13:24:01 +0100
commita2c55e04d5a1187914cba2c02810db94de499ace (patch)
treeeb7af207d40217a842ee487ba2c49d0eeda7064a /src/payload.c
parent80f5d7fd66895c651c9d1e35b2353f3020ffb538 (diff)
src: fix protocol context update on big-endian systems
There is an obscure bug on big-endian systems when trying to list a rule containing the expression 'ct helper tftp' which triggers the assert() call in mpz_get_type(). Florian identified the cause: ct_expr_pctx_update() is called for the relational expression which calls mpz_get_uint32() to get RHS value (assuming it is a protocol number). On big-endian systems, the misinterpreted value exceeds UINT_MAX. Expressions' pctx_update() callback should only be called for protocol matches, so ct_meta_common_postprocess() lacked a check for 'left->flags & EXPR_F_PROTOCOL' like the one already present in payload_expr_pctx_update(). In order to fix this in a clean way, this patch introduces a wrapper relational_expr_pctx_update() to be used instead of directly calling LHS's pctx_update() callback which unifies the necessary checks (and adds one more assert): - assert(expr->ops->type == EXPR_RELATIONAL) -> This is new, just to ensure the wrapper is called properly. - assert(expr->op == OP_EQ) -> This was moved from {ct,meta,payload}_expr_pctx_update(). - left->ops->pctx_update != NULL -> This was taken from expr_evaluate_relational(), a necessary requirement for the introduced wrapper to function at all. - (left->flags & EXPR_F_PROTOCOL) != 0 -> The crucial missing check which led to the problem. Suggested-by: Florian Westphal <> Signed-off-by: Phil Sutter <> Signed-off-by: Florian Westphal <>
Diffstat (limited to 'src/payload.c')
1 files changed, 1 insertions, 6 deletions
diff --git a/src/payload.c b/src/payload.c
index aa8a95ad..60090acc 100644
--- a/src/payload.c
+++ b/src/payload.c
@@ -84,11 +84,6 @@ static void payload_expr_pctx_update(struct proto_ctx *ctx,
const struct proto_desc *base, *desc;
unsigned int proto = 0;
- if (!(left->flags & EXPR_F_PROTOCOL))
- return;
- assert(expr->op == OP_EQ);
/* Export the data in the correct byte order */
assert(right->len / BITS_PER_BYTE <= sizeof(proto));
mpz_export_data(constant_data_ptr(proto, right->len), right->value,
@@ -240,7 +235,7 @@ static int payload_add_dependency(struct eval_ctx *ctx,
return expr_error(ctx->msgs, expr,
"dependency statement is invalid");
- left->ops->pctx_update(&ctx->pctx, dep);
+ relational_expr_pctx_update(&ctx->pctx, dep);
*res = stmt;
return 0;