[PATCH] scripts: kzfree.cocci: Deprecate use of kzfree

* [PATCH] scripts: kzfree.cocci: Deprecate use of kzfree
@ 2020-09-11 13:49 Alex Dewar
  2020-09-11 16:08 ` Denis Efremov
  0 siblings, 1 reply; 3+ messages in thread
From: Alex Dewar @ 2020-09-11 13:49 UTC (permalink / raw)
  Cc: Alex Dewar, Julia Lawall, Gilles Muller, Nicolas Palix,
	Michal Marek, Denis Efremov, Mauro Carvalho Chehab,
	Alexandre Belloni, Jonathan Corbet, cocci, linux-kernel

kzfree() is effectively deprecated as of commit 453431a54934 ("mm,
treewide: rename kzfree() to kfree_sensitive()"). It is currently just a
legacy alias for kfree_sensitive(), which achieves the same thing.

Update kzfree.cocci accordingly:
1) Replace instances of kzfree with kfree_sensitive
2) Merge different rules for memset/memset_explicit as kzfree and
   kfree_sensitive are now equivalent
3) Rename script to kfree_sensitive.cocci

In addition:
4) Move the script to the free/ subfolder, where it would seem to fit
   better

Signed-off-by: Alex Dewar <alex.dewar90@gmail.com>
---
 .../kfree_sensitive.cocci}                    | 38 +++++--------------
 1 file changed, 10 insertions(+), 28 deletions(-)
 rename scripts/coccinelle/{api/kzfree.cocci => free/kfree_sensitive.cocci} (59%)

diff --git a/scripts/coccinelle/api/kzfree.cocci b/scripts/coccinelle/free/kfree_sensitive.cocci
similarity index 59%
rename from scripts/coccinelle/api/kzfree.cocci
rename to scripts/coccinelle/free/kfree_sensitive.cocci
index 33625bd7cec9..a87f93f2ed5c 100644
--- a/scripts/coccinelle/api/kzfree.cocci
+++ b/scripts/coccinelle/free/kfree_sensitive.cocci
@@ -1,13 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0-only
 ///
-/// Use kzfree, kvfree_sensitive rather than memset or
-/// memzero_explicit followed by kfree
+/// Use k{,v}free_sensitive rather than memset or memzero_explicit followed by
+/// k{,v}free
 ///
 // Confidence: High
 // Copyright: (C) 2020 Denis Efremov ISPRAS
 // Options: --no-includes --include-headers
 //
-// Keywords: kzfree, kvfree_sensitive
+// Keywords: kfree_sensitive, kvfree_sensitive
 //
 
 virtual context
@@ -18,7 +18,7 @@ virtual report
 @initialize:python@
 @@
 # kmalloc_oob_in_memset uses memset to explicitly trigger out-of-bounds access
-filter = frozenset(['kmalloc_oob_in_memset', 'kzfree', 'kvfree_sensitive'])
+filter = frozenset(['kmalloc_oob_in_memset', 'kfree_sensitive', 'kvfree_sensitive'])
 
 def relevant(p):
     return not (filter & {el.current_element for el in p})
@@ -53,34 +53,16 @@ position m != cond.ok;
 type T;
 @@
 
+(
 - memzero_explicit@m((T)E, size);
-  ... when != E
-      when strict
-// TODO: uncomment when kfree_sensitive will be merged.
-// Only this case is commented out because developers
-// may not like patches like this since kzfree uses memset
-// internally (not memzero_explicit).
-//(
-//- kfree(E)@p;
-//+ kfree_sensitive(E);
-//|
-- \(vfree\|kvfree\)(E)@p;
-+ kvfree_sensitive(E, size);
-//)
-
-@rp_memset depends on patch@
-expression E, size;
-position p : script:python() { relevant(p) };
-position m != cond.ok;
-type T;
-@@
-
+|
 - memset@m((T)E, 0, size);
+)
   ... when != E
       when strict
 (
 - kfree(E)@p;
-+ kzfree(E);
++ kfree_sensitive(E);
 |
 - \(vfree\|kvfree\)(E)@p;
 + kvfree_sensitive(E, size);
@@ -91,11 +73,11 @@ p << r.p;
 @@
 
 coccilib.report.print_report(p[0],
-  "WARNING: opportunity for kzfree/kvfree_sensitive")
+  "WARNING: opportunity for k{,v}free_sensitive")
 
 @script:python depends on org@
 p << r.p;
 @@
 
 coccilib.org.print_todo(p[0],
-  "WARNING: opportunity for kzfree/kvfree_sensitive")
+  "WARNING: opportunity for k{,v}free_sensitive")
-- 
2.28.0


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