linux_dsm_epyc7002/scripts/coccinelle/free/kfree.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 a use after free.
//# Values of variables may imply that some
//# execution paths are not possible, resulting in false positives.
//# Another source of false positives are macros such as
//# SCTP_DBG_OBJCNT_DEC that do not actually evaluate their argument
///
// Confidence: Moderate
// Copyright: (C) 2010-2012 Nicolas Palix.
// Copyright: (C) 2010-2012 Julia Lawall, INRIA/LIP6.
// Copyright: (C) 2010-2012 Gilles Muller, INRIA/LiP6.
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options: --no-includes --include-headers
virtual org
virtual report
@free@
expression E;
position p1;
@@
(
* kfree@p1(E)
|
* kfree_sensitive@p1(E)
)
@print expression@
constant char [] c;
expression free.E,E2;
type T;
position p;
identifier f;
@@
(
f(...,c,...,(T)E@p,...)
|
E@p == E2
|
E@p != E2
|
E2 == E@p
|
E2 != E@p
|
!E@p
|
E@p || ...
)
@sz@
expression free.E;
position p;
@@
sizeof(<+...E@p...+>)
@loop exists@
expression E;
identifier l;
position ok;
@@
while (1) { ...
(
* kfree@ok(E)
|
* kfree_sensitive@ok(E)
)
... when != break;
when != goto l;
when forall
}
@r exists@
expression free.E, subE<=free.E, E2;
expression E1;
iterator iter;
statement S;
position free.p1!=loop.ok,p2!={print.p,sz.p};
@@
(
* kfree@p1(E,...)
|
* kfree_sensitive@p1(E,...)
)
...
(
iter(...,subE,...) S // no use
|
list_remove_head(E1,subE,...)
|
subE = E2
|
subE++
|
++subE
|
--subE
|
subE--
|
&subE
|
BUG(...)
|
BUG_ON(...)
|
return_VALUE(...)
|
return_ACPI_STATUS(...)
|
E@p2 // bad use
)
@script:python depends on org@
p1 << free.p1;
p2 << r.p2;
@@
cocci.print_main("kfree",p1)
cocci.print_secs("ref",p2)
@script:python depends on report@
p1 << free.p1;
p2 << r.p2;
@@
msg = "ERROR: reference preceded by free on line %s" % (p1[0].line)
coccilib.report.print_report(p2[0],msg)