linux-kernel - [PATCH 4.4 042/108] CIFS: zero sensitive data when freeing

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Message-Id: <20180215151228.322447988@linuxfoundation.org>
Date:   Thu, 15 Feb 2018 16:16:39 +0100
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Aurelien Aptel <aaptel@...e.com>,
        Steve French <smfrench@...il.com>,
        Pavel Shilovsky <pshilov@...rosoft.com>
Subject: [PATCH 4.4 042/108] CIFS: zero sensitive data when freeing

4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Aurelien Aptel <aaptel@...e.com>

commit 97f4b7276b829a8927ac903a119bef2f963ccc58 upstream.

also replaces memset()+kfree() by kzfree().

Signed-off-by: Aurelien Aptel <aaptel@...e.com>
Signed-off-by: Steve French <smfrench@...il.com>
Reviewed-by: Pavel Shilovsky <pshilov@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 fs/cifs/cifsencrypt.c |    3 +--
 fs/cifs/connect.c     |    6 +++---
 fs/cifs/misc.c        |   14 ++++----------
 3 files changed, 8 insertions(+), 15 deletions(-)

--- a/fs/cifs/cifsencrypt.c
+++ b/fs/cifs/cifsencrypt.c
@@ -306,9 +306,8 @@ int calc_lanman_hash(const char *passwor
 {
 	int i;
 	int rc;
-	char password_with_pad[CIFS_ENCPWD_SIZE];
+	char password_with_pad[CIFS_ENCPWD_SIZE] = {0};
 
-	memset(password_with_pad, 0, CIFS_ENCPWD_SIZE);
 	if (password)
 		strncpy(password_with_pad, password, CIFS_ENCPWD_SIZE);
 
--- a/fs/cifs/connect.c
+++ b/fs/cifs/connect.c
@@ -1695,7 +1695,7 @@ cifs_parse_mount_options(const char *mou
 			tmp_end++;
 			if (!(tmp_end < end && tmp_end[1] == delim)) {
 				/* No it is not. Set the password to NULL */
-				kfree(vol->password);
+				kzfree(vol->password);
 				vol->password = NULL;
 				break;
 			}
@@ -1733,7 +1733,7 @@ cifs_parse_mount_options(const char *mou
 					options = end;
 			}
 
-			kfree(vol->password);
+			kzfree(vol->password);
 			/* Now build new password string */
 			temp_len = strlen(value);
 			vol->password = kzalloc(temp_len+1, GFP_KERNEL);
@@ -4148,7 +4148,7 @@ cifs_construct_tcon(struct cifs_sb_info
 		reset_cifs_unix_caps(0, tcon, NULL, vol_info);
 out:
 	kfree(vol_info->username);
-	kfree(vol_info->password);
+	kzfree(vol_info->password);
 	kfree(vol_info);
 
 	return tcon;
--- a/fs/cifs/misc.c
+++ b/fs/cifs/misc.c
@@ -99,14 +99,11 @@ sesInfoFree(struct cifs_ses *buf_to_free
 	kfree(buf_to_free->serverOS);
 	kfree(buf_to_free->serverDomain);
 	kfree(buf_to_free->serverNOS);
-	if (buf_to_free->password) {
-		memset(buf_to_free->password, 0, strlen(buf_to_free->password));
-		kfree(buf_to_free->password);
-	}
+	kzfree(buf_to_free->password);
 	kfree(buf_to_free->user_name);
 	kfree(buf_to_free->domainName);
-	kfree(buf_to_free->auth_key.response);
-	kfree(buf_to_free);
+	kzfree(buf_to_free->auth_key.response);
+	kzfree(buf_to_free);
 }
 
 struct cifs_tcon *
@@ -137,10 +134,7 @@ tconInfoFree(struct cifs_tcon *buf_to_fr
 	}
 	atomic_dec(&tconInfoAllocCount);
 	kfree(buf_to_free->nativeFileSystem);
-	if (buf_to_free->password) {
-		memset(buf_to_free->password, 0, strlen(buf_to_free->password));
-		kfree(buf_to_free->password);
-	}
+	kzfree(buf_to_free->password);
 	kfree(buf_to_free);
 }