diff options
| author | Dr. Stephen Henson <steve@openssl.org> | 2014-09-25 23:28:48 +0100 |
|---|---|---|
| committer | Dr. Stephen Henson <steve@openssl.org> | 2014-09-29 12:01:05 +0100 |
| commit | 1cfd255c9123cdb4637cc9a65c6665fe4a06c6d5 (patch) | |
| tree | 86e26adccb01a6f970de107123649ea51c055d91 /crypto/rsa/rsa_sign.c | |
| parent | 3d81ec5b92e1141762eb72caf2aeb9b2cd019a78 (diff) | |
Add additional DigestInfo checks.
Reencode DigestInto in DER and check against the original: this
will reject any improperly encoded DigestInfo structures.
Note: this is a precautionary measure, there is no known attack
which can exploit this.
Thanks to Brian Smith for reporting this issue.
Reviewed-by: Tim Hudson <tjh@openssl.org>
Diffstat (limited to 'crypto/rsa/rsa_sign.c')
| -rw-r--r-- | crypto/rsa/rsa_sign.c | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/crypto/rsa/rsa_sign.c b/crypto/rsa/rsa_sign.c index fa3239ab30..748292550d 100644 --- a/crypto/rsa/rsa_sign.c +++ b/crypto/rsa/rsa_sign.c @@ -143,6 +143,25 @@ int RSA_sign(int type, const unsigned char *m, unsigned int m_len, return(ret); } +/* + * Check DigestInfo structure does not contain extraneous data by reencoding + * using DER and checking encoding against original. + */ +static int rsa_check_digestinfo(X509_SIG *sig, const unsigned char *dinfo, int dinfolen) + { + unsigned char *der = NULL; + int derlen; + int ret = 0; + derlen = i2d_X509_SIG(sig, &der); + if (derlen <= 0) + return 0; + if (derlen == dinfolen && !memcmp(dinfo, der, derlen)) + ret = 1; + OPENSSL_cleanse(der, derlen); + OPENSSL_free(der); + return ret; + } + int int_rsa_verify(int dtype, const unsigned char *m, unsigned int m_len, unsigned char *rm, size_t *prm_len, @@ -211,7 +230,7 @@ int int_rsa_verify(int dtype, const unsigned char *m, if (sig == NULL) goto err; /* Excess data can be used to create forgeries */ - if(p != s+i) + if(p != s+i || !rsa_check_digestinfo(sig, s, i)) { RSAerr(RSA_F_INT_RSA_VERIFY,RSA_R_BAD_SIGNATURE); goto err; |