Backport:

apr_crypto: Clear out buffers that are allocated by us when the pool from
which the memory was allocated from is cleaned up.


git-svn-id: http://svn.apache.org/repos/asf/apr/apr-util/branches/1.5.x@1210530 13f79535-47bb-0310-9956-ffa450edef68

4 files changed, 48 insertions, 0 deletions

diff --git a/crypto/apr_crypto.c b/crypto/apr_crypto.c
index 2352c703..2ca391a0 100644
--- a/crypto/apr_crypto.c
+++ b/crypto/apr_crypto.c
@@ -62,6 +62,11 @@ APR_TYPEDEF_STRUCT(apr_crypto_block_t,
     const apr_crypto_t *f;
 )
 
+typedef struct apr_crypto_clear_t {
+    void *buffer;
+    apr_size_t size;
+} apr_crypto_clear_t;
+
 #if !APU_DSO_BUILD
 #define DRIVER_LOAD(name,driver,pool,params) \
     {   \
@@ -124,6 +129,31 @@ APU_DECLARE(apr_status_t) apr_crypto_init(apr_pool_t *pool)
     return ret;
 }
 
+static apr_status_t crypto_clear(void *ptr)
+{
+    apr_crypto_clear_t *clear = (apr_crypto_clear_t *)ptr;
+
+    memset(clear->buffer, 0, clear->size);
+    clear->buffer = NULL;
+    clear->size = 0;
+
+    return APR_SUCCESS;
+}
+
+APR_DECLARE(apr_status_t) apr_crypto_clear(apr_pool_t *pool,
+        void *buffer, apr_size_t size)
+{
+    apr_crypto_clear_t *clear = apr_palloc(pool, sizeof(apr_crypto_clear_t));
+
+    clear->buffer = buffer;
+    clear->size = size;
+
+    apr_pool_cleanup_register(pool, clear, crypto_clear,
+            apr_pool_cleanup_null);
+
+    return APR_SUCCESS;
+}
+
 APU_DECLARE(apr_status_t) apr_crypto_get_driver(
         const apr_crypto_driver_t **driver, const char *name,
         const char *params, const apu_err_t **result, apr_pool_t *pool)
diff --git a/crypto/apr_crypto_nss.c b/crypto/apr_crypto_nss.c
index edc47cf1..d594542c 100644
--- a/crypto/apr_crypto_nss.c
+++ b/crypto/apr_crypto_nss.c
@@ -551,6 +551,7 @@ static apr_status_t crypto_block_encrypt_init(apr_crypto_block_t **ctx,
             if (!usedIv) {
                 return APR_ENOMEM;
             }
+            apr_crypto_clear(p, usedIv, key->ivSize);
             s = PK11_GenerateRandom(usedIv, key->ivSize);
             if (s != SECSuccess) {
                 return APR_ENOIV;
@@ -622,6 +623,7 @@ static apr_status_t crypto_block_encrypt(unsigned char **out,
         if (!buffer) {
             return APR_ENOMEM;
         }
+        apr_crypto_clear(block->pool, buffer, inlen + block->blockSize);
         *out = buffer;
     }
 
@@ -785,6 +787,7 @@ static apr_status_t crypto_block_decrypt(unsigned char **out,
         if (!buffer) {
             return APR_ENOMEM;
         }
+        apr_crypto_clear(block->pool, buffer, inlen + block->blockSize);
         *out = buffer;
     }
 
diff --git a/crypto/apr_crypto_openssl.c b/crypto/apr_crypto_openssl.c
index cbdb7685..97e6008e 100644
--- a/crypto/apr_crypto_openssl.c
+++ b/crypto/apr_crypto_openssl.c
@@ -430,6 +430,7 @@ static apr_status_t crypto_passphrase(apr_crypto_key_t **k, apr_size_t *ivSize,
     if (!key->key) {
         return APR_ENOMEM;
     }
+    apr_crypto_clear(p, key->key, key->keyLen);
 
     /* generate the key */
     if (PKCS5_PBKDF2_HMAC_SHA1(pass, passLen, (unsigned char *) salt, saltLen,
@@ -503,6 +504,7 @@ static apr_status_t crypto_block_encrypt_init(apr_crypto_block_t **ctx,
             if (!usedIv) {
                 return APR_ENOMEM;
             }
+            apr_crypto_clear(p, usedIv, key->ivSize);
             if (!((RAND_status() == 1)
                     && (RAND_bytes(usedIv, key->ivSize) == 1))) {
                 return APR_ENOIV;
@@ -574,6 +576,7 @@ static apr_status_t crypto_block_encrypt(unsigned char **out,
         if (!buffer) {
             return APR_ENOMEM;
         }
+        apr_crypto_clear(ctx->pool, buffer, inlen + EVP_MAX_BLOCK_LENGTH);
         *out = buffer;
     }
 
@@ -728,6 +731,7 @@ static apr_status_t crypto_block_decrypt(unsigned char **out,
         if (!buffer) {
             return APR_ENOMEM;
         }
+        apr_crypto_clear(ctx->pool, buffer, inlen + EVP_MAX_BLOCK_LENGTH);
         *out = buffer;
     }
 
diff --git a/include/apr_crypto.h b/include/apr_crypto.h
index 2b772d1f..9c5778be 100644
--- a/include/apr_crypto.h
+++ b/include/apr_crypto.h
@@ -132,6 +132,17 @@ typedef struct apr_crypto_block_t apr_crypto_block_t;
 APU_DECLARE(apr_status_t) apr_crypto_init(apr_pool_t *pool);
 
 /**
+ * @brief Register a cleanup to zero out the buffer provided
+ * when the pool is cleaned up.
+ *
+ * @param pool - pool to register the cleanup
+ * @param buffer - buffer to zero out
+ * @param size - size of the buffer to zero out
+ */
+APR_DECLARE(apr_status_t) apr_crypto_clear(apr_pool_t *pool, void *buffer,
+        apr_size_t size);
+
+/**
  * @brief Get the driver struct for a name
  *
  * @param driver - pointer to driver struct.