[PATCH v8 8/9] ima-evm-utils: Pass status codes from sign and hash functions to the callers

[Vitaly Chikunov <vt@xxxxxxxxxxxx>]

Move sign_hash()/ima_calc_hash()/calc_evm_hmac()/calc_evm_hash() status
checking before assert()'ing of their return values, so it can be passed
to the upper level callers. Especially useful for showing errors.

Fixes: 1d9c279279 ("Define hash and sig buffer sizes and add asserts")
Fixes: 9643544701 ("Fix hash buffer overflow in verify_evm and hmac_evm")
Signed-off-by: Vitaly Chikunov <vt@xxxxxxxxxxxx>

ima-evm-utils: Fix assert after ima_calc_hash
---
 src/evmctl.c    | 16 ++++++++--------
 src/libimaevm.c |  2 +-
 2 files changed, 9 insertions(+), 9 deletions(-)

diff --git a/src/evmctl.c b/src/evmctl.c
index 354d731..4e0a831 100644
--- a/src/evmctl.c
+++ b/src/evmctl.c
@@ -514,14 +514,14 @@ static int sign_evm(const char *file, const char *key)
 	int len, err;
 
 	len = calc_evm_hash(file, hash);
-	assert(len <= sizeof(hash));
 	if (len <= 1)
 		return len;
+	assert(len <= sizeof(hash));
 
 	len = sign_hash(params.hash_algo, hash, len, key, NULL, sig + 1);
-	assert(len < sizeof(sig));
 	if (len <= 1)
 		return len;
+	assert(len < sizeof(sig));
 
 	/* add header */
 	len++;
@@ -563,9 +563,9 @@ static int hash_ima(const char *file)
 	}
 
 	len = ima_calc_hash(file, hash + offset);
-	assert(len + offset <= sizeof(hash));
 	if (len <= 1)
 		return len;
+	assert(len + offset <= sizeof(hash));
 
 	len += offset;
 
@@ -593,14 +593,14 @@ static int sign_ima(const char *file, const char *key)
 	int len, err;
 
 	len = ima_calc_hash(file, hash);
-	assert(len <= sizeof(hash));
 	if (len <= 1)
 		return len;
+	assert(len <= sizeof(hash));
 
 	len = sign_hash(params.hash_algo, hash, len, key, NULL, sig + 1);
-	assert(len < sizeof(sig));
 	if (len <= 1)
 		return len;
+	assert(len < sizeof(sig));
 
 	/* add header */
 	len++;
@@ -724,9 +724,9 @@ static int cmd_sign_hash(struct command *cmd)
 		hex2bin(hash, line, hashlen / 2);
 		siglen = sign_hash(params.hash_algo, hash, hashlen/2,
 				 key, NULL, sig + 1);
-		assert(siglen < sizeof(sig));
 		if (siglen <= 1)
 			return siglen;
+		assert(siglen < sizeof(sig));
 
 		fwrite(line, len, 1, stdout);
 		fprintf(stdout, " ");
@@ -778,9 +778,9 @@ static int verify_evm(const char *file)
 	int len;
 
 	mdlen = calc_evm_hash(file, hash);
-	assert(mdlen <= sizeof(hash));
 	if (mdlen <= 1)
 		return mdlen;
+	assert(mdlen <= sizeof(hash));
 
 	len = lgetxattr(file, xattr_evm, sig, sizeof(sig));
 	if (len < 0) {
@@ -1160,9 +1160,9 @@ static int hmac_evm(const char *file, const char *key)
 	int len, err;
 
 	len = calc_evm_hmac(file, key, hash);
-	assert(len <= sizeof(hash));
 	if (len <= 1)
 		return len;
+	assert(len <= sizeof(hash));
 
 	log_info("hmac: ");
 	log_dump(hash, len);
diff --git a/src/libimaevm.c b/src/libimaevm.c
index d8e23a3..caf1237 100644
--- a/src/libimaevm.c
+++ b/src/libimaevm.c
@@ -618,9 +618,9 @@ int ima_verify_signature(const char *file, unsigned char *sig, int siglen,
 	    return verify_hash(file, digest, digestlen, sig + 1, siglen - 1);
 
 	hashlen = ima_calc_hash(file, hash);
-	assert(hashlen <= sizeof(hash));
 	if (hashlen <= 1)
 		return hashlen;
+	assert(hashlen <= sizeof(hash));
 
 	return verify_hash(file, hash, hashlen, sig + 1, siglen - 1);
 }
-- 
2.11.0