crypto/hash: avoid overwriting user supplied result pointer

If the user provides a pre-allocated buffer for the hash result,
we must use that rather than re-allocating a new buffer.

Reported-by: Dorjoy Chowdhury <dorjoychy111@gmail.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>

diff --git a/crypto/hash-gcrypt.c b/crypto/hash-gcrypt.c
index ccc3cce3f8ab647860da26d2bb417e178b893924..73533a49494ed8c1033f9fda48240eb7426c2775 100644 (file)
--- a/crypto/hash-gcrypt.c
+++ b/crypto/hash-gcrypt.c
@@ -103,16 +103,25 @@ int qcrypto_gcrypt_hash_finalize(QCryptoHash *hash,
                                  size_t *result_len,
                                  Error **errp)
 {
+    int ret;
     unsigned char *digest;
     gcry_md_hd_t *ctx = hash->opaque;
 
-    *result_len = gcry_md_get_algo_dlen(qcrypto_hash_alg_map[hash->alg]);
-    if (*result_len == 0) {
+    ret = gcry_md_get_algo_dlen(qcrypto_hash_alg_map[hash->alg]);
+    if (ret == 0) {
         error_setg(errp, "Unable to get hash length");
         return -1;
     }
 
-    *result = g_new(uint8_t, *result_len);
+    if (*result_len == 0) {
+        *result_len = ret;
+        *result = g_new(uint8_t, *result_len);
+    } else if (*result_len != ret) {
+        error_setg(errp,
+                   "Result buffer size %zu is smaller than hash %d",
+                   *result_len, ret);
+        return -1;
+    }
 
     /* Digest is freed by gcry_md_close(), copy it */
     digest = gcry_md_read(*ctx, 0);

diff --git a/crypto/hash-glib.c b/crypto/hash-glib.c
index 02a6ec1edf9f04cb405cbddc01ec5be52cad9505..809cef98aee4d8f86f84e6059349c6aa4e883464 100644 (file)
--- a/crypto/hash-glib.c
+++ b/crypto/hash-glib.c
@@ -99,8 +99,15 @@ int qcrypto_glib_hash_finalize(QCryptoHash *hash,
         return -1;
     }
 
-    *result_len = ret;
-    *result = g_new(uint8_t, *result_len);
+    if (*result_len == 0) {
+        *result_len = ret;
+        *result = g_new(uint8_t, *result_len);
+    } else if (*result_len != ret) {
+        error_setg(errp,
+                   "Result buffer size %zu is smaller than hash %d",
+                   *result_len, ret);
+        return -1;
+    }
 
     g_checksum_get_digest(ctx, *result, result_len);
     return 0;

diff --git a/crypto/hash-gnutls.c b/crypto/hash-gnutls.c
index 34a63994c9ff9e3ea9f4600aba88ba06cf1b5e9e..99fbe824ead8ce8f19bd28908fc01fb344ca2d65 100644 (file)
--- a/crypto/hash-gnutls.c
+++ b/crypto/hash-gnutls.c
@@ -115,14 +115,24 @@ int qcrypto_gnutls_hash_finalize(QCryptoHash *hash,
                                  Error **errp)
 {
     gnutls_hash_hd_t *ctx = hash->opaque;
+    int ret;
 
-    *result_len = gnutls_hash_get_len(qcrypto_hash_alg_map[hash->alg]);
-    if (*result_len == 0) {
+    ret = gnutls_hash_get_len(qcrypto_hash_alg_map[hash->alg]);
+    if (ret == 0) {
         error_setg(errp, "Unable to get hash length");
         return -1;
     }
 
-    *result = g_new(uint8_t, *result_len);
+    if (*result_len == 0) {
+        *result_len = ret;
+        *result = g_new(uint8_t, *result_len);
+    } else if (*result_len != ret) {
+        error_setg(errp,
+                   "Result buffer size %zu is smaller than hash %d",
+                   *result_len, ret);
+        return -1;
+    }
+
     gnutls_hash_output(*ctx, *result);
     return 0;
 }

diff --git a/crypto/hash-nettle.c b/crypto/hash-nettle.c
index 3b847aa60e8a4a968e2c94462b25d3e828d5539a..c78624b347271b4b7162360b676a90dcc41c0157 100644 (file)
--- a/crypto/hash-nettle.c
+++ b/crypto/hash-nettle.c
@@ -150,9 +150,17 @@ int qcrypto_nettle_hash_finalize(QCryptoHash *hash,
                                  Error **errp)
 {
     union qcrypto_hash_ctx *ctx = hash->opaque;
-
-    *result_len = qcrypto_hash_alg_map[hash->alg].len;
-    *result = g_new(uint8_t, *result_len);
+    int ret = qcrypto_hash_alg_map[hash->alg].len;
+
+    if (*result_len == 0) {
+        *result_len = ret;
+        *result = g_new(uint8_t, *result_len);
+    } else if (*result_len != ret) {
+        error_setg(errp,
+                   "Result buffer size %zu is smaller than hash %d",
+                   *result_len, ret);
+        return -1;
+    }
 
     qcrypto_hash_alg_map[hash->alg].result(ctx, *result_len, *result);