Merge pull request #8182 from daverodgman/asn1write-size
Reduce code size in mbedtls_asn1_write_len
diff --git a/library/asn1write.c b/library/asn1write.c
index 4123ac3..2e9b98a 100644
--- a/library/asn1write.c
+++ b/library/asn1write.c
@@ -28,68 +28,40 @@
#include "mbedtls/platform.h"
+#if defined(MBEDTLS_ASN1_PARSE_C)
+#include "mbedtls/asn1.h"
+#endif
+
int mbedtls_asn1_write_len(unsigned char **p, const unsigned char *start, size_t len)
{
- if (len < 0x80) {
- if (*p - start < 1) {
- return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
- }
-
- *--(*p) = (unsigned char) len;
- return 1;
- }
-
- if (len <= 0xFF) {
- if (*p - start < 2) {
- return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
- }
-
- *--(*p) = (unsigned char) len;
- *--(*p) = 0x81;
- return 2;
- }
-
- if (len <= 0xFFFF) {
- if (*p - start < 3) {
- return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
- }
-
- *--(*p) = MBEDTLS_BYTE_0(len);
- *--(*p) = MBEDTLS_BYTE_1(len);
- *--(*p) = 0x82;
- return 3;
- }
-
- if (len <= 0xFFFFFF) {
- if (*p - start < 4) {
- return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
- }
-
- *--(*p) = MBEDTLS_BYTE_0(len);
- *--(*p) = MBEDTLS_BYTE_1(len);
- *--(*p) = MBEDTLS_BYTE_2(len);
- *--(*p) = 0x83;
- return 4;
- }
-
- int len_is_valid = 1;
#if SIZE_MAX > 0xFFFFFFFF
- len_is_valid = (len <= 0xFFFFFFFF);
+ if (len > 0xFFFFFFFF) {
+ return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
+ }
#endif
- if (len_is_valid) {
- if (*p - start < 5) {
- return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
- }
- *--(*p) = MBEDTLS_BYTE_0(len);
- *--(*p) = MBEDTLS_BYTE_1(len);
- *--(*p) = MBEDTLS_BYTE_2(len);
- *--(*p) = MBEDTLS_BYTE_3(len);
- *--(*p) = 0x84;
- return 5;
+ int required = 1;
+
+ if (len >= 0x80) {
+ for (size_t l = len; l != 0; l >>= 8) {
+ required++;
+ }
}
- return MBEDTLS_ERR_ASN1_INVALID_LENGTH;
+ if (required > (*p - start)) {
+ return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
+ }
+
+ do {
+ *--(*p) = MBEDTLS_BYTE_0(len);
+ len >>= 8;
+ } while (len);
+
+ if (required > 1) {
+ *--(*p) = (unsigned char) (0x80 + required - 1);
+ }
+
+ return required;
}
int mbedtls_asn1_write_tag(unsigned char **p, const unsigned char *start, unsigned char tag)
@@ -105,6 +77,19 @@
#endif /* MBEDTLS_ASN1_WRITE_C || MBEDTLS_X509_USE_C */
#if defined(MBEDTLS_ASN1_WRITE_C)
+static int mbedtls_asn1_write_len_and_tag(unsigned char **p,
+ const unsigned char *start,
+ size_t len,
+ unsigned char tag)
+{
+ int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
+
+ MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
+ MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, tag));
+
+ return (int) len;
+}
+
int mbedtls_asn1_write_raw_buffer(unsigned char **p, const unsigned char *start,
const unsigned char *buf, size_t size)
{
@@ -156,10 +141,7 @@
len += 1;
}
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_INTEGER));
-
- ret = (int) len;
+ ret = mbedtls_asn1_write_len_and_tag(p, start, len, MBEDTLS_ASN1_INTEGER);
cleanup:
return ret;
@@ -168,15 +150,9 @@
int mbedtls_asn1_write_null(unsigned char **p, const unsigned char *start)
{
- int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
- size_t len = 0;
-
// Write NULL
//
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, 0));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_NULL));
-
- return (int) len;
+ return mbedtls_asn1_write_len_and_tag(p, start, 0, MBEDTLS_ASN1_NULL);
}
int mbedtls_asn1_write_oid(unsigned char **p, const unsigned char *start,
@@ -187,10 +163,7 @@
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start,
(const unsigned char *) oid, oid_len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OID));
-
- return (int) len;
+ return mbedtls_asn1_write_len_and_tag(p, start, len, MBEDTLS_ASN1_OID);
}
int mbedtls_asn1_write_algorithm_identifier(unsigned char **p, const unsigned char *start,
@@ -217,17 +190,12 @@
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_oid(p, start, oid, oid_len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start,
- MBEDTLS_ASN1_CONSTRUCTED |
- MBEDTLS_ASN1_SEQUENCE));
-
- return (int) len;
+ return mbedtls_asn1_write_len_and_tag(p, start, len,
+ MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE);
}
int mbedtls_asn1_write_bool(unsigned char **p, const unsigned char *start, int boolean)
{
- int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
if (*p - start < 1) {
@@ -237,15 +205,11 @@
*--(*p) = (boolean) ? 255 : 0;
len++;
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_BOOLEAN));
-
- return (int) len;
+ return mbedtls_asn1_write_len_and_tag(p, start, len, MBEDTLS_ASN1_BOOLEAN);
}
static int asn1_write_tagged_int(unsigned char **p, const unsigned char *start, int val, int tag)
{
- int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
do {
@@ -265,10 +229,7 @@
len += 1;
}
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, tag));
-
- return (int) len;
+ return mbedtls_asn1_write_len_and_tag(p, start, len, tag);
}
int mbedtls_asn1_write_int(unsigned char **p, const unsigned char *start, int val)
@@ -291,10 +252,7 @@
(const unsigned char *) text,
text_len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, tag));
-
- return (int) len;
+ return mbedtls_asn1_write_len_and_tag(p, start, len, tag);
}
int mbedtls_asn1_write_utf8_string(unsigned char **p, const unsigned char *start,
@@ -363,7 +321,6 @@
int mbedtls_asn1_write_bitstring(unsigned char **p, const unsigned char *start,
const unsigned char *buf, size_t bits)
{
- int ret = MBEDTLS_ERR_ERROR_CORRUPTION_DETECTED;
size_t len = 0;
size_t unused_bits, byte_len;
@@ -387,10 +344,7 @@
/* Write unused bits */
*--(*p) = (unsigned char) unused_bits;
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_BIT_STRING));
-
- return (int) len;
+ return mbedtls_asn1_write_len_and_tag(p, start, len, MBEDTLS_ASN1_BIT_STRING);
}
int mbedtls_asn1_write_octet_string(unsigned char **p, const unsigned char *start,
@@ -401,13 +355,11 @@
MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_raw_buffer(p, start, buf, size));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_len(p, start, len));
- MBEDTLS_ASN1_CHK_ADD(len, mbedtls_asn1_write_tag(p, start, MBEDTLS_ASN1_OCTET_STRING));
-
- return (int) len;
+ return mbedtls_asn1_write_len_and_tag(p, start, len, MBEDTLS_ASN1_OCTET_STRING);
}
+#if !defined(MBEDTLS_ASN1_PARSE_C)
/* This is a copy of the ASN.1 parsing function mbedtls_asn1_find_named_data(),
* which is replicated to avoid a dependency ASN1_WRITE_C on ASN1_PARSE_C. */
static mbedtls_asn1_named_data *asn1_find_named_data(
@@ -425,6 +377,10 @@
return list;
}
+#else
+#define asn1_find_named_data(list, oid, len) \
+ ((mbedtls_asn1_named_data *) mbedtls_asn1_find_named_data(list, oid, len))
+#endif
mbedtls_asn1_named_data *mbedtls_asn1_store_named_data(
mbedtls_asn1_named_data **head,