From 582f1f41d49b5bf5ceaca241356d5f9c986f230f Mon Sep 17 00:00:00 2001 From: Emilia Kasper Date: Tue, 12 May 2015 19:00:30 +0200 Subject: [PATCH] PKCS#7: Fix NULL dereference with missing EncryptedContent. CVE-2015-1790 Reviewed-by: Rich Salz --- crypto/pkcs7/pk7_doit.c | 16 +++++++++++++++- 1 file changed, 15 insertions(+), 1 deletion(-) diff --git a/crypto/pkcs7/pk7_doit.c b/crypto/pkcs7/pk7_doit.c index db134ddcc3..0a12f03257 100644 --- a/crypto/pkcs7/pk7_doit.c +++ b/crypto/pkcs7/pk7_doit.c @@ -359,12 +359,19 @@ BIO *PKCS7_dataDecode(PKCS7 *p7, EVP_PKEY *pkey, BIO *in_bio, X509 *pcert) switch (i) { case NID_pkcs7_signed: + /* + * p7->d.sign->contents is a PKCS7 structure consisting of a contentType + * field and optional content. + * data_body is NULL if that structure has no (=detached) content + * or if the contentType is wrong (i.e., not "data"). + */ data_body = PKCS7_get_octet_string(p7->d.sign->contents); md_sk = p7->d.sign->md_algs; break; case NID_pkcs7_signedAndEnveloped: rsk = p7->d.signed_and_enveloped->recipientinfo; md_sk = p7->d.signed_and_enveloped->md_algs; + /* data_body is NULL if the optional EncryptedContent is missing. */ data_body = p7->d.signed_and_enveloped->enc_data->enc_data; enc_alg = p7->d.signed_and_enveloped->enc_data->algorithm; evp_cipher = EVP_get_cipherbyobj(enc_alg->algorithm); @@ -377,6 +384,7 @@ BIO *PKCS7_dataDecode(PKCS7 *p7, EVP_PKEY *pkey, BIO *in_bio, X509 *pcert) case NID_pkcs7_enveloped: rsk = p7->d.enveloped->recipientinfo; enc_alg = p7->d.enveloped->enc_data->algorithm; + /* data_body is NULL if the optional EncryptedContent is missing. */ data_body = p7->d.enveloped->enc_data->enc_data; evp_cipher = EVP_get_cipherbyobj(enc_alg->algorithm); if (evp_cipher == NULL) { @@ -390,6 +398,12 @@ BIO *PKCS7_dataDecode(PKCS7 *p7, EVP_PKEY *pkey, BIO *in_bio, X509 *pcert) goto err; } + /* Detached content must be supplied via in_bio instead. */ + if (data_body == NULL && in_bio == NULL) { + PKCS7err(PKCS7_F_PKCS7_DATADECODE, PKCS7_R_NO_CONTENT); + goto err; + } + /* We will be checking the signature */ if (md_sk != NULL) { for (i = 0; i < sk_X509_ALGOR_num(md_sk); i++) { @@ -557,7 +571,7 @@ BIO *PKCS7_dataDecode(PKCS7 *p7, EVP_PKEY *pkey, BIO *in_bio, X509 *pcert) etmp = NULL; } #if 1 - if (PKCS7_is_detached(p7) || (in_bio != NULL)) { + if (in_bio != NULL) { bio = in_bio; } else { # if 0