diff options
author | Dr. Stephen Henson <steve@openssl.org> | 2012-03-12 16:31:39 +0000 |
---|---|---|
committer | Dr. Stephen Henson <steve@openssl.org> | 2012-03-12 16:31:39 +0000 |
commit | 146b52edd122f55e2b2bfeb486dae8dbe96f739e (patch) | |
tree | b097163337fabe71cc7d2861c4ae7c91f3babc98 /crypto/cms/cms_smime.c | |
parent | 13747c6fdabbba33cb187a133548b73d41ae282d (diff) |
Fix for CMS/PKCS7 MMA. If RSA decryption fails use a random key and
continue with symmetric decryption process to avoid leaking timing
information to an attacker.
Thanks to Ivan Nestlerode <inestlerode@us.ibm.com> for discovering
this issue. (CVE-2012-0884)
Diffstat (limited to 'crypto/cms/cms_smime.c')
-rw-r--r-- | crypto/cms/cms_smime.c | 37 |
1 files changed, 33 insertions, 4 deletions
diff --git a/crypto/cms/cms_smime.c b/crypto/cms/cms_smime.c index a40307605b..8c56e3a852 100644 --- a/crypto/cms/cms_smime.c +++ b/crypto/cms/cms_smime.c @@ -611,7 +611,10 @@ int CMS_decrypt_set1_pkey(CMS_ContentInfo *cms, EVP_PKEY *pk, X509 *cert) STACK_OF(CMS_RecipientInfo) *ris; CMS_RecipientInfo *ri; int i, r; + int debug = 0; ris = CMS_get0_RecipientInfos(cms); + if (ris) + debug = cms->d.envelopedData->encryptedContentInfo->debug; for (i = 0; i < sk_CMS_RecipientInfo_num(ris); i++) { ri = sk_CMS_RecipientInfo_value(ris, i); @@ -625,17 +628,38 @@ int CMS_decrypt_set1_pkey(CMS_ContentInfo *cms, EVP_PKEY *pk, X509 *cert) CMS_RecipientInfo_set0_pkey(ri, pk); r = CMS_RecipientInfo_decrypt(cms, ri); CMS_RecipientInfo_set0_pkey(ri, NULL); - if (r > 0) - return 1; if (cert) { + /* If not debugging clear any error and + * return success to avoid leaking of + * information useful to MMA + */ + if (!debug) + { + ERR_clear_error(); + return 1; + } + if (r > 0) + return 1; CMSerr(CMS_F_CMS_DECRYPT_SET1_PKEY, CMS_R_DECRYPT_ERROR); return 0; } - ERR_clear_error(); + /* If no cert and not debugging don't leave loop + * after first successful decrypt. Always attempt + * to decrypt all recipients to avoid leaking timing + * of a successful decrypt. + */ + else if (r > 0 && debug) + return 1; } } + /* If no cert and not debugging always return success */ + if (!cert && !debug) + { + ERR_clear_error(); + return 1; + } CMSerr(CMS_F_CMS_DECRYPT_SET1_PKEY, CMS_R_NO_MATCHING_RECIPIENT); return 0; @@ -718,9 +742,14 @@ int CMS_decrypt(CMS_ContentInfo *cms, EVP_PKEY *pk, X509 *cert, } if (!dcont && !check_content(cms)) return 0; + if (flags & CMS_DEBUG_DECRYPT) + cms->d.envelopedData->encryptedContentInfo->debug = 1; + else + cms->d.envelopedData->encryptedContentInfo->debug = 0; + if (!pk && !cert && !dcont && !out) + return 1; if (pk && !CMS_decrypt_set1_pkey(cms, pk, cert)) return 0; - cont = CMS_dataInit(cms, dcont); if (!cont) return 0; |