Add new mbedtls_pkcs5_pbe2_ext function
Add new mbedtls_pkcs5_pbe2_ext function to replace old
function with possible security issues.
Signed-off-by: Waleed Elmelegy <waleed.elmelegy@arm.com>
diff --git a/library/pkcs5.c b/library/pkcs5.c
index bbbe82c..ec8dc66 100644
--- a/library/pkcs5.c
+++ b/library/pkcs5.c
@@ -44,6 +44,14 @@
#include "mbedtls/platform.h"
+#if !defined(MBEDTLS_CIPHER_PADDING_PKCS7)
+int mbedtls_pkcs5_pbes2_ext(const mbedtls_asn1_buf *pbe_params, int mode,
+ const unsigned char *pwd, size_t pwdlen,
+ const unsigned char *data, size_t datalen,
+ unsigned char *output, size_t output_size,
+ size_t *output_len);
+#endif
+
#if defined(MBEDTLS_ASN1_PARSE_C)
static int pkcs5_parse_pbkdf2_params(const mbedtls_asn1_buf *params,
mbedtls_asn1_buf *salt, int *iterations,
@@ -114,18 +122,34 @@
const unsigned char *data, size_t datalen,
unsigned char *output)
{
+ size_t output_len = 0;
+
+ /* We assume caller of the function is providing a big enough output buffer
+ * so we pass output_size as SIZE_MAX to pass checks, However, no gurantees
+ * for the output size actually being correct.
+ */
+ return mbedtls_pkcs5_pbes2_ext(pbe_params, mode, pwd, pwdlen, data,
+ datalen, output, SIZE_MAX, &output_len);
+}
+
+int mbedtls_pkcs5_pbes2_ext(const mbedtls_asn1_buf *pbe_params, int mode,
+ const unsigned char *pwd, size_t pwdlen,
+ const unsigned char *data, size_t datalen,
+ unsigned char *output, size_t output_size,
+ size_t *output_len)
+{
int ret, iterations = 0, keylen = 0;
unsigned char *p, *end;
mbedtls_asn1_buf kdf_alg_oid, enc_scheme_oid, kdf_alg_params, enc_scheme_params;
mbedtls_asn1_buf salt;
mbedtls_md_type_t md_type = MBEDTLS_MD_SHA1;
unsigned char key[32], iv[32];
- size_t olen = 0;
const mbedtls_md_info_t *md_info;
const mbedtls_cipher_info_t *cipher_info;
mbedtls_md_context_t md_ctx;
mbedtls_cipher_type_t cipher_alg;
mbedtls_cipher_context_t cipher_ctx;
+ unsigned int padlen = 0;
p = pbe_params->p;
end = p + pbe_params->len;
@@ -188,7 +212,21 @@
return MBEDTLS_ERR_PKCS5_INVALID_FORMAT;
}
+ if (mode == MBEDTLS_PKCS5_DECRYPT) {
+ if (output_size < datalen) {
+ return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
+ }
+ }
+
+ if (mode == MBEDTLS_PKCS5_ENCRYPT) {
+ padlen = cipher_info->block_size - (datalen % cipher_info->block_size);
+ if (output_size < (datalen + padlen)) {
+ return MBEDTLS_ERR_ASN1_BUF_TOO_SMALL;
+ }
+ }
+
mbedtls_md_init(&md_ctx);
+
mbedtls_cipher_init(&cipher_ctx);
memcpy(iv, enc_scheme_params.p, enc_scheme_params.len);
@@ -232,7 +270,7 @@
}
#endif /* MBEDTLS_CIPHER_MODE_WITH_PADDING */
if ((ret = mbedtls_cipher_crypt(&cipher_ctx, iv, enc_scheme_params.len,
- data, datalen, output, &olen)) != 0) {
+ data, datalen, output, output_len)) != 0) {
ret = MBEDTLS_ERR_PKCS5_PASSWORD_MISMATCH;
}