linux_dsm_epyc7002/scripts/coccinelle/free/devm_free.cocci
Waiman Long 453431a549 mm, treewide: rename kzfree() to kfree_sensitive()
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>
2020-08-07 11:33:22 -07:00

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// SPDX-License-Identifier: GPL-2.0-only
/// Find uses of standard freeing functons on values allocated using devm_
/// functions. Values allocated using the devm_functions are freed when
/// the device is detached, and thus the use of the standard freeing
/// function would cause a double free.
/// See Documentation/driver-api/driver-model/devres.rst for more information.
///
/// A difficulty of detecting this problem is that the standard freeing
/// function might be called from a different function than the one
/// containing the allocation function. It is thus necessary to make the
/// connection between the allocation function and the freeing function.
/// Here this is done using the specific argument text, which is prone to
/// false positives. There is no rule for the request_region and
/// request_mem_region variants because this heuristic seems to be a bit
/// less reliable in these cases.
///
// Confidence: Moderate
// Copyright: (C) 2011 Julia Lawall, INRIA/LIP6.
// Copyright: (C) 2011 Gilles Muller, INRIA/LiP6.
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options: --no-includes --include-headers
virtual org
virtual report
virtual context
@r depends on context || org || report@
expression x;
@@
(
x = devm_kmalloc(...)
|
x = devm_kvasprintf(...)
|
x = devm_kasprintf(...)
|
x = devm_kzalloc(...)
|
x = devm_kmalloc_array(...)
|
x = devm_kcalloc(...)
|
x = devm_kstrdup(...)
|
x = devm_kmemdup(...)
|
x = devm_get_free_pages(...)
|
x = devm_request_irq(...)
|
x = devm_ioremap(...)
|
x = devm_ioport_map(...)
)
@safe depends on context || org || report exists@
expression x;
position p;
@@
(
x = kmalloc(...)
|
x = kvasprintf(...)
|
x = kasprintf(...)
|
x = kzalloc(...)
|
x = kmalloc_array(...)
|
x = kcalloc(...)
|
x = kstrdup(...)
|
x = kmemdup(...)
|
x = get_free_pages(...)
|
x = request_irq(...)
|
x = ioremap(...)
|
x = ioport_map(...)
)
...
(
kfree@p(x)
|
kfree_sensitive@p(x)
|
krealloc@p(x, ...)
|
free_pages@p(x, ...)
|
free_page@p(x)
|
free_irq@p(x)
|
iounmap@p(x)
|
ioport_unmap@p(x)
)
@pb@
expression r.x;
position p != safe.p;
@@
(
* kfree@p(x)
|
* kfree_sensitive@p(x)
|
* krealloc@p(x, ...)
|
* free_pages@p(x, ...)
|
* free_page@p(x)
|
* free_irq@p(x)
|
* iounmap@p(x)
|
* ioport_unmap@p(x)
)
@script:python depends on org@
p << pb.p;
@@
msg="WARNING: invalid free of devm_ allocated data"
coccilib.org.print_todo(p[0], msg)
@script:python depends on report@
p << pb.p;
@@
msg="WARNING: invalid free of devm_ allocated data"
coccilib.report.print_report(p[0], msg)