[PATCH nft v2] payload: fix endianess issue in payload_expr_pctx_update()

[Pablo Neira Ayuso <pablo@netfilter.org>]

Use constant_data_ptr() to point to the right memory position on
big endian when exporting data that is stored in a larger variable.

Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
v2: this also fixes the printing of 1 byte fields that are converted to
    symbolic constant.

 src/datatype.c |    4 ++--
 src/payload.c  |    4 ++--
 2 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/src/datatype.c b/src/datatype.c
index fd3573e..729e63b 100644
--- a/src/datatype.c
+++ b/src/datatype.c
@@ -158,8 +158,8 @@ void symbolic_constant_print(const struct symbol_table *tbl,
 
 	/* Export the data in the correct byteorder for comparison */
 	assert(expr->len / BITS_PER_BYTE <= sizeof(val));
-	mpz_export_data(&val, expr->value, expr->byteorder,
-			expr->len / BITS_PER_BYTE);
+	mpz_export_data(constant_data_ptr(val, expr->len), expr->value,
+			expr->byteorder, expr->len / BITS_PER_BYTE);
 
 	for (s = tbl->symbols; s->identifier != NULL; s++) {
 		if (val == s->value)
diff --git a/src/payload.c b/src/payload.c
index ebf8079..83742fb 100644
--- a/src/payload.c
+++ b/src/payload.c
@@ -79,8 +79,8 @@ static void payload_expr_pctx_update(struct proto_ctx *ctx,
 
 	/* Export the data in the correct byte order */
 	assert(right->len / BITS_PER_BYTE <= sizeof(proto));
-	mpz_export_data(&proto, right->value, right->byteorder,
-			right->len / BITS_PER_BYTE);
+	mpz_export_data(constant_data_ptr(proto, right->len), right->value,
+			right->byteorder, right->len / BITS_PER_BYTE);
 
 	base = ctx->protocol[left->payload.base].desc;
 	desc = proto_find_upper(base, proto);
-- 
1.7.10.4