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mm, treewide: rename kzfree() to kfree_sensitive()

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As said by Linus:

  A symmetric naming is only helpful if it implies symmetries in use.
  Otherwise it's actively misleading.

  In "kzalloc()", the z is meaningful and an important part of what the
  caller wants.

  In "kzfree()", the z is actively detrimental, because maybe in the
  future we really _might_ want to use that "memfill(0xdeadbeef)" or
  something. The "zero" part of the interface isn't even _relevant_.

The main reason that kzfree() exists is to clear sensitive information
that should not be leaked to other future users of the same memory
objects.

Rename kzfree() to kfree_sensitive() to follow the example of the recently
added kvfree_sensitive() and make the intention of the API more explicit.
In addition, memzero_explicit() is used to clear the memory to make sure
that it won't get optimized away by the compiler.

The renaming is done by using the command sequence:

  git grep -w --name-only kzfree |\
  xargs sed -i 's/kzfree/kfree_sensitive/'

followed by some editing of the kfree_sensitive() kerneldoc and adding
a kzfree backward compatibility macro in slab.h.

[akpm@linux-foundation.org: fs/crypto/inline_crypt.c needs linux/slab.h]
[akpm@linux-foundation.org: fix fs/crypto/inline_crypt.c some more]

Suggested-by: Joe Perches <joe@perches.com>
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Joe Perches <joe@perches.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dan Carpenter <dan.carpenter@oracle.com>
Cc: "Jason A . Donenfeld" <Jason@zx2c4.com>
Link: http://lkml.kernel.org/r/20200616154311.12314-3-longman@redhat.com
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Waiman Long
2020-08-06 23:18:13 -07:00
committed by Linus Torvalds
parent 57c720d414
commit 453431a549
114 changed files with 323 additions and 320 deletions
Download Patch File Download Diff File Expand all files Collapse all files

10
fs/cifs/connect.c
View File

@@ -2182,7 +2182,7 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
tmp_end++;
if (!(tmp_end < end && tmp_end[1] == delim)) {
/* No it is not. Set the password to NULL */
kzfree(vol->password);
kfree_sensitive(vol->password);
vol->password = NULL;
break;
}
@@ -2220,7 +2220,7 @@ cifs_parse_mount_options(const char *mountdata, const char *devname,
options = end;
}
kzfree(vol->password);
kfree_sensitive(vol->password);
/* Now build new password string */
temp_len = strlen(value);
vol->password = kzalloc(temp_len+1, GFP_KERNEL);
@@ -3198,7 +3198,7 @@ cifs_set_cifscreds(struct smb_vol *vol, struct cifs_ses *ses)
rc = -ENOMEM;
kfree(vol->username);
vol->username = NULL;
kzfree(vol->password);
kfree_sensitive(vol->password);
vol->password = NULL;
goto out_key_put;
}
@@ -4219,7 +4219,7 @@ void
cifs_cleanup_volume_info_contents(struct smb_vol *volume_info)
{
kfree(volume_info->username);
kzfree(volume_info->password);
kfree_sensitive(volume_info->password);
kfree(volume_info->UNC);
kfree(volume_info->domainname);
kfree(volume_info->iocharset);
@@ -5345,7 +5345,7 @@ cifs_construct_tcon(struct cifs_sb_info *cifs_sb, kuid_t fsuid)
out:
kfree(vol_info->username);
kzfree(vol_info->password);
kfree_sensitive(vol_info->password);
kfree(vol_info);
return tcon;