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Merge pull request #8804 from valeriosetti/issue8799

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mbedtls_rsa_parse_key and mbedtls_rsa_parse_pubkey accept trailing garbage
This commit is contained in:
Manuel Pégourié-Gonnard
2024-02-20 11:58:52 +00:00
committed by GitHub
parent 9fb53a9e26 7e1596d24c
commit a7f651cf16
9 changed files with 92 additions and 26 deletions
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45
library/pem.c
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@ -240,6 +240,29 @@ exit:
}
#endif /* MBEDTLS_AES_C */
#if defined(MBEDTLS_DES_C) || defined(MBEDTLS_AES_C)
static int pem_check_pkcs_padding(unsigned char *input, size_t input_len, size_t *data_len)
{
/* input_len > 0 is guaranteed by mbedtls_pem_read_buffer(). */
size_t pad_len = input[input_len - 1];
size_t i;
if (pad_len > input_len) {
return MBEDTLS_ERR_PEM_PASSWORD_MISMATCH;
}
*data_len = input_len - pad_len;
for (i = *data_len; i < input_len; i++) {
if (input[i] != pad_len) {
return MBEDTLS_ERR_PEM_PASSWORD_MISMATCH;
}
}
return 0;
}
#endif /* MBEDTLS_DES_C || MBEDTLS_AES_C */
#endif /* PEM_RFC1421 */
int mbedtls_pem_read_buffer(mbedtls_pem_context *ctx, const char *header, const char *footer,
@ -389,6 +412,10 @@ int mbedtls_pem_read_buffer(mbedtls_pem_context *ctx, const char *header, const
return MBEDTLS_ERROR_ADD(MBEDTLS_ERR_PEM_INVALID_DATA, ret);
}
if (len == 0) {
return MBEDTLS_ERR_PEM_BAD_INPUT_DATA;
}
if ((buf = mbedtls_calloc(1, len)) == NULL) {
return MBEDTLS_ERR_PEM_ALLOC_FAILED;
}
@ -426,20 +453,20 @@ int mbedtls_pem_read_buffer(mbedtls_pem_context *ctx, const char *header, const
#endif /* MBEDTLS_AES_C */
if (ret != 0) {
mbedtls_free(buf);
mbedtls_zeroize_and_free(buf, len);
return ret;
}
/*
* The result will be ASN.1 starting with a SEQUENCE tag, with 1 to 3
* length bytes (allow 4 to be sure) in all known use cases.
*
* Use that as a heuristic to try to detect password mismatches.
*/
if (len <= 2 || buf[0] != 0x30 || buf[1] > 0x83) {
/* Check PKCS padding and update data length based on padding info.
* This can be used to detect invalid padding data and password
* mismatches. */
size_t unpadded_len;
ret = pem_check_pkcs_padding(buf, len, &unpadded_len);
if (ret != 0) {
mbedtls_zeroize_and_free(buf, len);
return MBEDTLS_ERR_PEM_PASSWORD_MISMATCH;
return ret;
}
len = unpadded_len;
#else
mbedtls_zeroize_and_free(buf, len);
return MBEDTLS_ERR_PEM_FEATURE_UNAVAILABLE;

10
library/rsa.c
View File

@ -108,8 +108,9 @@ int mbedtls_rsa_parse_key(mbedtls_rsa_context *rsa, const unsigned char *key, si
return ret;
}
/* mbedtls_asn1_get_tag() already ensures that len is valid (i.e. p+len <= end)*/
end = p + len;
if (end != p + len) {
return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
}
if ((ret = mbedtls_asn1_get_int(&p, end, &version)) != 0) {
return ret;
@ -241,8 +242,9 @@ int mbedtls_rsa_parse_pubkey(mbedtls_rsa_context *rsa, const unsigned char *key,
return ret;
}
/* mbedtls_asn1_get_tag() already ensures that len is valid (i.e. p+len <= end)*/
end = p + len;
if (end != p + len) {
return MBEDTLS_ERR_RSA_BAD_INPUT_DATA;
}
/* Import N */
if ((ret = mbedtls_asn1_get_tag(&p, end, &len, MBEDTLS_ASN1_INTEGER)) != 0) {