[PATCH v2 3/4] smb: client: Make generate_key() return void

[Eric Biggers <ebiggers@kernel.org>]

Since the crypto library API is now being used instead of crypto_shash,
generate_key() can no longer fail.  Make it return void and simplify the
callers accordingly.

Reviewed-by: Ard Biesheuvel <ardb@kernel.org>
Signed-off-by: Eric Biggers <ebiggers@kernel.org>
---
 fs/smb/client/smb2transport.c | 45 +++++++++++++----------------------
 1 file changed, 16 insertions(+), 29 deletions(-)

diff --git a/fs/smb/client/smb2transport.c b/fs/smb/client/smb2transport.c
index 716e58d1b1c92..0176185a1efcb 100644
--- a/fs/smb/client/smb2transport.c
+++ b/fs/smb/client/smb2transport.c
@@ -249,12 +249,12 @@ smb2_calc_signature(struct smb_rqst *rqst, struct TCP_Server_Info *server,
 		memcpy(shdr->Signature, smb2_signature, SMB2_SIGNATURE_SIZE);
 
 	return rc;
 }
 
-static int generate_key(struct cifs_ses *ses, struct kvec label,
-			struct kvec context, __u8 *key, unsigned int key_size)
+static void generate_key(struct cifs_ses *ses, struct kvec label,
+			 struct kvec context, __u8 *key, unsigned int key_size)
 {
 	unsigned char zero = 0x0;
 	__u8 i[4] = {0, 0, 0, 1};
 	__u8 L128[4] = {0, 0, 0, 128};
 	__u8 L256[4] = {0, 0, 1, 0};
@@ -279,11 +279,10 @@ static int generate_key(struct cifs_ses *ses, struct kvec label,
 		hmac_sha256_update(&hmac_ctx, L128, 4);
 	}
 	hmac_sha256_final(&hmac_ctx, prfhash);
 
 	memcpy(key, prfhash, key_size);
-	return 0;
 }
 
 struct derivation {
 	struct kvec label;
 	struct kvec context;
@@ -298,11 +297,10 @@ struct derivation_triplet {
 static int
 generate_smb3signingkey(struct cifs_ses *ses,
 			struct TCP_Server_Info *server,
 			const struct derivation_triplet *ptriplet)
 {
-	int rc;
 	bool is_binding = false;
 	int chan_index = 0;
 
 	spin_lock(&ses->ses_lock);
 	spin_lock(&ses->chan_lock);
@@ -329,42 +327,31 @@ generate_smb3signingkey(struct cifs_ses *ses,
 	 * key and store it in the channel as to not overwrite the
 	 * master connection signing key stored in the session
 	 */
 
 	if (is_binding) {
-		rc = generate_key(ses, ptriplet->signing.label,
-				  ptriplet->signing.context,
-				  ses->chans[chan_index].signkey,
-				  SMB3_SIGN_KEY_SIZE);
-		if (rc)
-			return rc;
+		generate_key(ses, ptriplet->signing.label,
+			     ptriplet->signing.context,
+			     ses->chans[chan_index].signkey,
+			     SMB3_SIGN_KEY_SIZE);
 	} else {
-		rc = generate_key(ses, ptriplet->signing.label,
-				  ptriplet->signing.context,
-				  ses->smb3signingkey,
-				  SMB3_SIGN_KEY_SIZE);
-		if (rc)
-			return rc;
+		generate_key(ses, ptriplet->signing.label,
+			     ptriplet->signing.context,
+			     ses->smb3signingkey, SMB3_SIGN_KEY_SIZE);
 
 		/* safe to access primary channel, since it will never go away */
 		spin_lock(&ses->chan_lock);
 		memcpy(ses->chans[chan_index].signkey, ses->smb3signingkey,
 		       SMB3_SIGN_KEY_SIZE);
 		spin_unlock(&ses->chan_lock);
 
-		rc = generate_key(ses, ptriplet->encryption.label,
-				  ptriplet->encryption.context,
-				  ses->smb3encryptionkey,
-				  SMB3_ENC_DEC_KEY_SIZE);
-		if (rc)
-			return rc;
-		rc = generate_key(ses, ptriplet->decryption.label,
-				  ptriplet->decryption.context,
-				  ses->smb3decryptionkey,
-				  SMB3_ENC_DEC_KEY_SIZE);
-		if (rc)
-			return rc;
+		generate_key(ses, ptriplet->encryption.label,
+			     ptriplet->encryption.context,
+			     ses->smb3encryptionkey, SMB3_ENC_DEC_KEY_SIZE);
+		generate_key(ses, ptriplet->decryption.label,
+			     ptriplet->decryption.context,
+			     ses->smb3decryptionkey, SMB3_ENC_DEC_KEY_SIZE);
 	}
 
 #ifdef CONFIG_CIFS_DEBUG_DUMP_KEYS
 	cifs_dbg(VFS, "%s: dumping generated AES session keys\n", __func__);
 	/*
@@ -389,11 +376,11 @@ generate_smb3signingkey(struct cifs_ses *ses,
 				SMB3_GCM128_CRYPTKEY_SIZE, ses->smb3encryptionkey);
 		cifs_dbg(VFS, "ServerOut Key %*ph\n",
 				SMB3_GCM128_CRYPTKEY_SIZE, ses->smb3decryptionkey);
 	}
 #endif
-	return rc;
+	return 0;
 }
 
 int
 generate_smb30signingkey(struct cifs_ses *ses,
 			 struct TCP_Server_Info *server)
-- 
2.53.0