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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

2
drivers/net/wireless/intel/iwlwifi/pcie/rx.c
View File

@@ -1369,7 +1369,7 @@ static void iwl_pcie_rx_handle_rb(struct iwl_trans *trans,
&rxcb, rxq->id);
if (reclaim) {
kzfree(txq->entries[cmd_index].free_buf);
kfree_sensitive(txq->entries[cmd_index].free_buf);
txq->entries[cmd_index].free_buf = NULL;
}

6
drivers/net/wireless/intel/iwlwifi/pcie/tx-gen2.c
View File

@@ -1026,7 +1026,7 @@ static int iwl_pcie_gen2_enqueue_hcmd(struct iwl_trans *trans,
BUILD_BUG_ON(IWL_TFH_NUM_TBS > sizeof(out_meta->tbs) * BITS_PER_BYTE);
out_meta->flags = cmd->flags;
if (WARN_ON_ONCE(txq->entries[idx].free_buf))
kzfree(txq->entries[idx].free_buf);
kfree_sensitive(txq->entries[idx].free_buf);
txq->entries[idx].free_buf = dup_buf;
trace_iwlwifi_dev_hcmd(trans->dev, cmd, cmd_size, &out_cmd->hdr_wide);
@@ -1257,8 +1257,8 @@ static void iwl_pcie_gen2_txq_free(struct iwl_trans *trans, int txq_id)
/* De-alloc array of command/tx buffers */
if (txq_id == trans->txqs.cmd.q_id)
for (i = 0; i < txq->n_window; i++) {
kzfree(txq->entries[i].cmd);
kzfree(txq->entries[i].free_buf);
kfree_sensitive(txq->entries[i].cmd);
kfree_sensitive(txq->entries[i].free_buf);
}
del_timer_sync(&txq->stuck_timer);

6
drivers/net/wireless/intel/iwlwifi/pcie/tx.c
View File

@@ -721,8 +721,8 @@ static void iwl_pcie_txq_free(struct iwl_trans *trans, int txq_id)
/* De-alloc array of command/tx buffers */
if (txq_id == trans->txqs.cmd.q_id)
for (i = 0; i < txq->n_window; i++) {
kzfree(txq->entries[i].cmd);
kzfree(txq->entries[i].free_buf);
kfree_sensitive(txq->entries[i].cmd);
kfree_sensitive(txq->entries[i].free_buf);
}
/* De-alloc circular buffer of TFDs */
@@ -1765,7 +1765,7 @@ static int iwl_pcie_enqueue_hcmd(struct iwl_trans *trans,
BUILD_BUG_ON(IWL_TFH_NUM_TBS > sizeof(out_meta->tbs) * BITS_PER_BYTE);
out_meta->flags = cmd->flags;
if (WARN_ON_ONCE(txq->entries[idx].free_buf))
kzfree(txq->entries[idx].free_buf);
kfree_sensitive(txq->entries[idx].free_buf);
txq->entries[idx].free_buf = dup_buf;
trace_iwlwifi_dev_hcmd(trans->dev, cmd, cmd_size, &out_cmd->hdr_wide);

4
drivers/net/wireless/intersil/orinoco/wext.c
View File

@@ -31,8 +31,8 @@ static int orinoco_set_key(struct orinoco_private *priv, int index,
enum orinoco_alg alg, const u8 *key, int key_len,
const u8 *seq, int seq_len)
{
kzfree(priv->keys[index].key);
kzfree(priv->keys[index].seq);
kfree_sensitive(priv->keys[index].key);
kfree_sensitive(priv->keys[index].seq);
if (key_len) {
priv->keys[index].key = kzalloc(key_len, GFP_ATOMIC);