[RFC PATCH ima-evm-utils 07/11] Add missing EVP_MD_CTX_free() call in calc_evm_hash()

[Mimi Zohar <zohar@xxxxxxxxxxxxx>]

When EVP_MD_CTX_new() call was added, the corresponding EVP_MD_CTX_free()
was never called.  Properly free it.

Fixes: 81010f0d87ef ("ima-evm-utils: Add backward compatible support for openssl 1.1")
Signed-off-by: Mimi Zohar <zohar@xxxxxxxxxxxxx>
---
 src/evmctl.c | 57 ++++++++++++++++++++++++++++++++++++----------------
 1 file changed, 40 insertions(+), 17 deletions(-)

diff --git a/src/evmctl.c b/src/evmctl.c
index 913b85f6b620..490d355188d0 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -331,11 +331,17 @@ err:
 	return -1;
 }
 
+/*
+ * calc_evm_hash - calculate the file metadata hash
+ *
+ * Returns 0 for EVP_ function failures. Return -1 for other failures.
+ * Return hash algorithm size on success.
+ */
 static int calc_evm_hash(const char *file, unsigned char *hash)
 {
         const EVP_MD *md;
 	struct stat st;
-	int err;
+	int err = -1;
 	uint32_t generation = 0;
 	EVP_MD_CTX *pctx;
 	unsigned int mdlen;
@@ -349,12 +355,11 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
 #if OPENSSL_VERSION_NUMBER < 0x10100000
 	EVP_MD_CTX ctx;
 	pctx = &ctx;
-#else
-	pctx = EVP_MD_CTX_new();
 #endif
 
 	if (lstat(file, &st)) {
 		log_err("Failed to stat: %s\n", file);
+		errno = 0;
 		return -1;
 	}
 
@@ -391,20 +396,30 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
 	list_size = llistxattr(file, list, sizeof(list));
 	if (list_size < 0) {
 		log_err("llistxattr() failed\n");
+		errno = 0;
 		return -1;
 	}
 
+#if OPENSSL_VERSION_NUMBER >= 0x10100000
+	pctx = EVP_MD_CTX_new();
+	if (!pctx) {
+		log_err("EVP_MD_CTX_new() failed\n");
+		return 0;
+	}
+#endif
+
 	md = EVP_get_digestbyname(imaevm_params.hash_algo);
 	if (!md) {
 		log_err("EVP_get_digestbyname(%s) failed\n",
 			imaevm_params.hash_algo);
-		return 1;
+		err = 0;
+		goto out;
 	}
 
 	err = EVP_DigestInit(pctx, md);
 	if (!err) {
 		log_err("EVP_DigestInit() failed\n");
-		return 1;
+		goto out;
 	}
 
 	for (xattrname = evm_config_xattrnames; *xattrname != NULL; xattrname++) {
@@ -415,7 +430,8 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
 			if (err > sizeof(xattr_value)) {
 				log_err("selinux[%u] value is too long to fit into xattr[%zu]\n",
 					err, sizeof(xattr_value));
-				return -1;
+				err = -1;
+				goto out;
 			}
 			strcpy(xattr_value, selinux_str);
 		} else if (!strcmp(*xattrname, XATTR_NAME_IMA) && ima_str) {
@@ -423,7 +439,8 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
 			if (err > sizeof(xattr_value)) {
 				log_err("ima[%u] value is too long to fit into xattr[%zu]\n",
 					err, sizeof(xattr_value));
-				return -1;
+				err = -1;
+				goto out;
 			}
 			hex2bin(xattr_value, ima_str, err);
 		} else if (!strcmp(*xattrname, XATTR_NAME_IMA) && evm_portable){
@@ -432,7 +449,7 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
 			if (err < 0) {
 				log_err("EVM portable sig: %s required\n",
 					xattr_ima);
-				return -1;
+				goto out;
 			}
 			use_xattr_ima = 1;
 		} else if (!strcmp(*xattrname, XATTR_NAME_CAPS) && (hmac_flags & HMAC_FLAG_CAPS_SET)) {
@@ -442,7 +459,8 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
 			if (err >= sizeof(xattr_value)) {
 				log_err("caps[%u] value is too long to fit into xattr[%zu]\n",
 					err + 1, sizeof(xattr_value));
-				return -1;
+				err = -1;
+				goto out;
 			}
 			strcpy(xattr_value, caps_str);
 		} else {
@@ -463,7 +481,7 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
 		err = EVP_DigestUpdate(pctx, xattr_value, err);
 		if (!err) {
 			log_err("EVP_DigestUpdate() failed\n");
-			return 1;
+			goto out;
 		}
 	}
 
@@ -517,29 +535,33 @@ static int calc_evm_hash(const char *file, unsigned char *hash)
 	err = EVP_DigestUpdate(pctx, &hmac_misc, hmac_size);
 	if (!err) {
 		log_err("EVP_DigestUpdate() failed\n");
-		return 1;
+		goto out;
 	}
 
 	if (!evm_immutable && !evm_portable &&
 	    !(hmac_flags & HMAC_FLAG_NO_UUID)) {
 		err = get_uuid(&st, uuid);
 		if (err)
-			return -1;
+			goto out;
 
 		err = EVP_DigestUpdate(pctx, (const unsigned char *)uuid, sizeof(uuid));
 		if (!err) {
 			log_err("EVP_DigestUpdate() failed\n");
-			return 1;
+			goto out;
 		}
 	}
 
 	err = EVP_DigestFinal(pctx, hash, &mdlen);
-	if (!err) {
+	if (!err)
 		log_err("EVP_DigestFinal() failed\n");
-		return 1;
-	}
 
-	return mdlen;
+out:
+#if OPENSSL_VERSION_NUMBER >= 0x10100000
+	EVP_MD_CTX_free(pctx);
+#endif
+	if (err == 1)
+		return mdlen;
+	return err;
 }
 
 static int sign_evm(const char *file, const char *key)
@@ -575,6 +597,7 @@ static int sign_evm(const char *file, const char *key)
 		err = lsetxattr(file, xattr_evm, sig, len, 0);
 		if (err < 0) {
 			log_err("setxattr failed: %s\n", file);
+			errno = 0;
 			return err;
 		}
 	}
-- 
2.31.1