linux-kernel - [PATCH] security: keys: Use kvfree

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Message-Id: <20200911114400.82207-1-alex.dewar90@gmail.com>
Date:   Fri, 11 Sep 2020 12:44:00 +0100
From:   Alex Dewar <alex.dewar90@...il.com>
To:     unlisted-recipients:; (no To-header on input)
Cc:     Alex Dewar <alex.dewar90@...il.com>,
        David Howells <dhowells@...hat.com>,
        Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>,
        James Morris <jmorris@...ei.org>,
        "Serge E. Hallyn" <serge@...lyn.com>, keyrings@...r.kernel.org,
        linux-security-module@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] security: keys: Use kvfree_sensitive in a few places

In big_key.c, there are a few places where memzero_explicit + kvfree is
used. It is better to use kvfree_sensitive instead, which is more
readable and also prevents the compiler from eliding the call to
memzero_explicit. Fix this.

Signed-off-by: Alex Dewar <alex.dewar90@...il.com>
---
 security/keys/big_key.c | 9 +++------
 1 file changed, 3 insertions(+), 6 deletions(-)

diff --git a/security/keys/big_key.c b/security/keys/big_key.c
index 691347dea3c1..d17e5f09eeb8 100644
--- a/security/keys/big_key.c
+++ b/security/keys/big_key.c
@@ -121,8 +121,7 @@ int big_key_preparse(struct key_preparsed_payload *prep)
 		*path = file->f_path;
 		path_get(path);
 		fput(file);
-		memzero_explicit(buf, enclen);
-		kvfree(buf);
+		kvfree_sensitive(buf, enclen);
 	} else {
 		/* Just store the data in a buffer */
 		void *data = kmalloc(datalen, GFP_KERNEL);
@@ -140,8 +139,7 @@ int big_key_preparse(struct key_preparsed_payload *prep)
 err_enckey:
 	kfree_sensitive(enckey);
 error:
-	memzero_explicit(buf, enclen);
-	kvfree(buf);
+	kvfree_sensitive(buf, enclen);
 	return ret;
 }
 
@@ -273,8 +271,7 @@ long big_key_read(const struct key *key, char *buffer, size_t buflen)
 err_fput:
 		fput(file);
 error:
-		memzero_explicit(buf, enclen);
-		kvfree(buf);
+		kvfree_sensitive(buf, enclen);
 	} else {
 		ret = datalen;
 		memcpy(buffer, key->payload.data[big_key_data], datalen);
-- 
2.28.0