X-Git-Url: https://git.stg.codes/stg.git/blobdiff_plain/b27841d687ec9e84983340b5581376dfb24010ea..b2b89723a2427bba8290bd6967a1ab39cbb630be:/libs/smux/der_encoder.c

diff --git a/libs/smux/der_encoder.c b/libs/smux/der_encoder.c
index 1c014802..2c6a6f76 100644
--- a/libs/smux/der_encoder.c
+++ b/libs/smux/der_encoder.c
@@ -12,19 +12,17 @@ static ssize_t der_write_TL(ber_tlv_tag_t tag, ber_tlv_len_t len,
  * The DER encoder of any type.
  */
 asn_enc_rval_t
-der_encode(asn_TYPE_descriptor_t *type_descriptor, void *struct_ptr,
-	asn_app_consume_bytes_f *consume_bytes, void *app_key) {
-
-	ASN_DEBUG("DER encoder invoked for %s",
+der_encode(const asn_TYPE_descriptor_t *type_descriptor, const void *struct_ptr,
+           asn_app_consume_bytes_f *consume_bytes, void *app_key) {
+    ASN_DEBUG("DER encoder invoked for %s",
 		type_descriptor->name);
 
 	/*
 	 * Invoke type-specific encoder.
 	 */
-	return type_descriptor->der_encoder(type_descriptor,
-		struct_ptr,	/* Pointer to the destination structure */
-		0, 0,
-		consume_bytes, app_key);
+    return type_descriptor->op->der_encoder(
+        type_descriptor, struct_ptr, /* Pointer to the destination structure */
+        0, 0, consume_bytes, app_key);
 }
 
 /*
@@ -51,15 +49,15 @@ static int encode_to_buffer_cb(const void *buffer, size_t size, void *key) {
  * A variant of the der_encode() which encodes the data into the provided buffer
  */
 asn_enc_rval_t
-der_encode_to_buffer(asn_TYPE_descriptor_t *type_descriptor, void *struct_ptr,
-	void *buffer, size_t buffer_size) {
-	enc_to_buf_arg arg;
+der_encode_to_buffer(const asn_TYPE_descriptor_t *type_descriptor,
+                     const void *struct_ptr, void *buffer, size_t buffer_size) {
+    enc_to_buf_arg arg;
 	asn_enc_rval_t ec;
 
 	arg.buffer = buffer;
 	arg.left = buffer_size;
 
-	ec = type_descriptor->der_encoder(type_descriptor,
+	ec = type_descriptor->op->der_encoder(type_descriptor,
 		struct_ptr,	/* Pointer to the destination structure */
 		0, 0, encode_to_buffer_cb, &arg);
 	if(ec.encoded != -1) {
@@ -74,19 +72,20 @@ der_encode_to_buffer(asn_TYPE_descriptor_t *type_descriptor, void *struct_ptr,
  * Write out leading TL[v] sequence according to the type definition.
  */
 ssize_t
-der_write_tags(asn_TYPE_descriptor_t *sd,
-		size_t struct_length,
-		int tag_mode, int last_tag_form,
-		ber_tlv_tag_t tag,	/* EXPLICIT or IMPLICIT tag */
-		asn_app_consume_bytes_f *cb,
-		void *app_key) {
-	const ber_tlv_tag_t *tags;	/* Copy of tags stream */
-	int tags_count;			/* Number of tags */
-	size_t overall_length;
-	ssize_t *lens;
-	int i;
-
-	ASN_DEBUG("Writing tags (%s, tm=%d, tc=%d, tag=%s, mtc=%d)",
+der_write_tags(const asn_TYPE_descriptor_t *sd, size_t struct_length,
+               int tag_mode, int last_tag_form,
+               ber_tlv_tag_t tag, /* EXPLICIT or IMPLICIT tag */
+               asn_app_consume_bytes_f *cb, void *app_key) {
+#define ASN1_DER_MAX_TAGS_COUNT 4
+    ber_tlv_tag_t
+        tags_buf_scratch[ASN1_DER_MAX_TAGS_COUNT * sizeof(ber_tlv_tag_t)];
+    ssize_t lens[ASN1_DER_MAX_TAGS_COUNT * sizeof(ssize_t)];
+    const ber_tlv_tag_t *tags; /* Copy of tags stream */
+    int tags_count;            /* Number of tags */
+    size_t overall_length;
+    int i;
+
+    ASN_DEBUG("Writing tags (%s, tm=%d, tc=%d, tag=%s, mtc=%d)",
 		sd->name, tag_mode, sd->tags_count,
 		ber_tlv_tag_string(tag),
 		tag_mode
@@ -95,6 +94,11 @@ der_write_tags(asn_TYPE_descriptor_t *sd,
 			:sd->tags_count
 	);
 
+    if(sd->tags_count + 1 > ASN1_DER_MAX_TAGS_COUNT) {
+        ASN_DEBUG("System limit %d on tags count", ASN1_DER_MAX_TAGS_COUNT);
+        return -1;
+    }
+
 	if(tag_mode) {
 		/*
 		 * Instead of doing shaman dance like we do in ber_check_tags(),
@@ -102,12 +106,7 @@ der_write_tags(asn_TYPE_descriptor_t *sd,
 		 * and initialize it appropriately.
 		 */
 		int stag_offset;
-		ber_tlv_tag_t *tags_buf;
-		tags_buf = (ber_tlv_tag_t *)alloca((sd->tags_count + 1) * sizeof(ber_tlv_tag_t));
-		if(!tags_buf) {	/* Can fail on !x86 */
-			errno = ENOMEM;
-			return -1;
-		}
+		ber_tlv_tag_t *tags_buf = tags_buf_scratch;
 		tags_count = sd->tags_count
 			+ 1	/* EXPLICIT or IMPLICIT tag is given */
 			- ((tag_mode == -1) && sd->tags_count);
@@ -126,12 +125,6 @@ der_write_tags(asn_TYPE_descriptor_t *sd,
 	if(tags_count == 0)
 		return 0;
 
-	lens = (ssize_t *)alloca(tags_count * sizeof(lens[0]));
-	if(!lens) {
-		errno = ENOMEM;
-		return -1;
-	}
-
 	/*
 	 * Array of tags is initialized.
 	 * Now, compute the size of the TLV pairs, from right to left.
@@ -146,8 +139,8 @@ der_write_tags(asn_TYPE_descriptor_t *sd,
 
 	if(!cb) return overall_length - struct_length;
 
-	ASN_DEBUG("%s %s TL sequence (%d elements)",
-		cb?"Encoding":"Estimating", sd->name, tags_count);
+	ASN_DEBUG("Encoding %s TL sequence (%d elements)", sd->name,
+                  tags_count);
 
 	/*
 	 * Encode the TL sequence for real.