Make sure PEM_SealInit() will correctly destroy the PEM_ENCODE_SEAL_CTX

upon error, as there is no way to do this outside of PEM_SealFinal(), which
can only work if PEM_SealInit() succeeded...

ok beck@ jsing@

1 files changed, 22 insertions, 8 deletions

diff --git a/src/lib/libcrypto/pem/pem_seal.c b/src/lib/libcrypto/pem/pem_seal.c
index 96687eb77f..79162b32d7 100644
--- a/src/lib/libcrypto/pem/pem_seal.c
+++ b/src/lib/libcrypto/pem/pem_seal.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: pem_seal.c,v 1.22 2015/09/10 15:56:25 jsing Exp $ */
+/* $OpenBSD: pem_seal.c,v 1.23 2016/11/05 11:32:45 miod Exp $ */
 /* Copyright (C) 1995-1998 Eric Young (eay@cryptsoft.com)
  * All rights reserved.
  *
@@ -70,6 +70,14 @@
 #include <openssl/rsa.h>
 #include <openssl/x509.h>
 
+static void
+PEM_ENCODE_SEAL_CTX_cleanup(PEM_ENCODE_SEAL_CTX *ctx)
+{
+        EVP_CIPHER_CTX_cleanup(&ctx->cipher);
+        EVP_MD_CTX_cleanup(&ctx->md);
+        explicit_bzero(&ctx->encode, sizeof(ctx->encode));
+}
+
 int
 PEM_SealInit(PEM_ENCODE_SEAL_CTX *ctx, EVP_CIPHER *type, EVP_MD *md_type,
     unsigned char **ek, int *ekl, unsigned char *iv, EVP_PKEY **pubk, int npubk)
@@ -79,6 +87,14 @@ PEM_SealInit(PEM_ENCODE_SEAL_CTX *ctx, EVP_CIPHER *type, EVP_MD *md_type,
         int i, j, max = 0;
         char *s = NULL;
 
+        /*
+         * Make sure ctx is properly initialized so that we can always pass
+         * it to PEM_ENCODE_SEAL_CTX_cleanup() in the error path.
+         */
+        EVP_EncodeInit(&ctx->encode);
+        EVP_MD_CTX_init(&ctx->md);
+        EVP_CIPHER_CTX_init(&ctx->cipher);
+
         for (i = 0; i < npubk; i++) {
                 if (pubk[i]->type != EVP_PKEY_RSA) {
                         PEMerr(PEM_F_PEM_SEALINIT, PEM_R_PUBLIC_KEY_NO_RSA);
@@ -94,13 +110,9 @@ PEM_SealInit(PEM_ENCODE_SEAL_CTX *ctx, EVP_CIPHER *type, EVP_MD *md_type,
                 goto err;
         }
 
-        EVP_EncodeInit(&ctx->encode);
-
-        EVP_MD_CTX_init(&ctx->md);
         if (!EVP_SignInit(&ctx->md, md_type))
                 goto err;
 
-        EVP_CIPHER_CTX_init(&ctx->cipher);
         ret = EVP_SealInit(&ctx->cipher, type, ek, ekl, iv, pubk, npubk);
         if (ret <= 0)
                 goto err;
@@ -115,9 +127,12 @@ PEM_SealInit(PEM_ENCODE_SEAL_CTX *ctx, EVP_CIPHER *type, EVP_MD *md_type,
 
         ret = npubk;
 
+        if (0) {
 err:
+                PEM_ENCODE_SEAL_CTX_cleanup(ctx);
+        }
         free(s);
-        explicit_bzero(key, EVP_MAX_KEY_LENGTH);
+        explicit_bzero(key, sizeof(key));
         return (ret);
 }
 
@@ -182,8 +197,7 @@ PEM_SealFinal(PEM_ENCODE_SEAL_CTX *ctx, unsigned char *sig, int *sigl,
         ret = 1;
 
 err:
-        EVP_MD_CTX_cleanup(&ctx->md);
-        EVP_CIPHER_CTX_cleanup(&ctx->cipher);
+        PEM_ENCODE_SEAL_CTX_cleanup(ctx);
         free(s);
         return (ret);
 }