[PATCH 3.16 171/410] CIFS: zero sensitive data when freeing

From: Ben Hutchings
Date: Thu Jun 07 2018 - 10:41:25 EST


3.16.57-rc1 review patch. If anyone has any objections, please let me know.

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

From: Aurelien Aptel <aaptel@xxxxxxxx>

commit 97f4b7276b829a8927ac903a119bef2f963ccc58 upstream.

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

Signed-off-by: Aurelien Aptel <aaptel@xxxxxxxx>
Signed-off-by: Steve French <smfrench@xxxxxxxxx>
Reviewed-by: Pavel Shilovsky <pshilov@xxxxxxxxxxxxx>
Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx>
---
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
@@ -303,9 +303,8 @@ 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
@@ -1614,7 +1614,7 @@ 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;
}
@@ -1652,7 +1652,7 @@ 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);
@@ -4039,7 +4039,7 @@ 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);
}