[PATCH v8] coccinelle: api: add kfree_mismatch script

From: Denis Efremov
Date: Fri Oct 16 2020 - 04:55:19 EST


Check that alloc and free types of functions match each other.

Signed-off-by: Denis Efremov <efremov@xxxxxxxxx>
---
Changes in v2:
- Lines are limited to 80 characters where possible
- Confidence changed from High to Medium because of
fs/btrfs/send.c:1119 false-positive
- __vmalloc_area_node() explicitly excluded from analysis
instead of !(file in "mm/vmalloc.c") condition
Changes in v3:
- prints style in org && report modes changed for python2
Changes in v4:
- missing msg argument to print_todo fixed
Changes in v5:
- fix position p in kfree rule
- move @kok and @v positions in choice rule after the arguments
- remove kvmalloc suggestions
Changes in v6:
- more asterisks added in context mode
- second @kok added to the choice rule
Changes in v7:
- file renamed to kfree_mismatch.cocci
- python function relevant() removed
- additional rule for filtering free positions added
- btrfs false-positive fixed
- confidence level changed to high
- kvfree_switch rule added
- names for position variables changed to @a (alloc) and @f (free)
Changes in v8:
- kzfree() replaced with kfree_sensitive()
- "position f != free.fok;" simplified to "position f;" in patch
and kvfree_switch rules

scripts/coccinelle/api/kfree_mismatch.cocci | 229 ++++++++++++++++++++
1 file changed, 229 insertions(+)
create mode 100644 scripts/coccinelle/api/kfree_mismatch.cocci

diff --git a/scripts/coccinelle/api/kfree_mismatch.cocci b/scripts/coccinelle/api/kfree_mismatch.cocci
new file mode 100644
index 000000000000..843b794fac7b
--- /dev/null
+++ b/scripts/coccinelle/api/kfree_mismatch.cocci
@@ -0,0 +1,229 @@
+// SPDX-License-Identifier: GPL-2.0-only
+///
+/// Check that kvmalloc'ed memory is freed by kfree functions,
+/// vmalloc'ed by vfree functions and kvmalloc'ed by kvfree
+/// functions.
+///
+// Confidence: High
+// Copyright: (C) 2020 Denis Efremov ISPRAS
+// Options: --no-includes --include-headers
+//
+
+virtual patch
+virtual report
+virtual org
+virtual context
+
+@alloc@
+expression E, E1;
+position kok, vok;
+@@
+
+(
+ if (...) {
+ ...
+ E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|
+ kmalloc_node\|kzalloc_node\|kmalloc_array\|
+ kmalloc_array_node\|kcalloc_node\)(...)@kok
+ ...
+ } else {
+ ...
+ E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|
+ vzalloc_node\|vmalloc_exec\|vmalloc_32\|
+ vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|
+ __vmalloc_node\)(...)@vok
+ ...
+ }
+|
+ E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|kzalloc_node\|
+ kmalloc_array\|kmalloc_array_node\|kcalloc_node\)(...)@kok
+ ... when != E = E1
+ when any
+ if (E == NULL) {
+ ...
+ E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|
+ vzalloc_node\|vmalloc_exec\|vmalloc_32\|
+ vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|
+ __vmalloc_node\)(...)@vok
+ ...
+ }
+)
+
+@free@
+expression E;
+position fok;
+@@
+
+ E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
+ kvmalloc_array\)(...)
+ ...
+ kvfree(E)@fok
+
+@vfree depends on !patch@
+expression E;
+position a != alloc.kok;
+position f != free.fok;
+@@
+
+* E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|
+* kzalloc_node\|kmalloc_array\|kmalloc_array_node\|
+* kcalloc_node\)(...)@a
+ ... when != if (...) { ... E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|__vmalloc_node\)(...); ... }
+ when != is_vmalloc_addr(E)
+ when any
+* \(vfree\|vfree_atomic\|kvfree\)(E)@f
+
+@depends on patch exists@
+expression E;
+position a != alloc.kok;
+position f != free.fok;
+@@
+
+ E = \(kmalloc\|kzalloc\|krealloc\|kcalloc\|kmalloc_node\|
+ kzalloc_node\|kmalloc_array\|kmalloc_array_node\|
+ kcalloc_node\)(...)@a
+ ... when != if (...) { ... E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|__vmalloc_node_range\|__vmalloc_node\)(...); ... }
+ when != is_vmalloc_addr(E)
+ when any
+- \(vfree\|vfree_atomic\|kvfree\)(E)@f
++ kfree(E)
+
+@kfree depends on !patch@
+expression E;
+position a != alloc.vok;
+position f != free.fok;
+@@
+
+* E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|
+* vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|
+* __vmalloc_node_range\|__vmalloc_node\)(...)@a
+ ... when != is_vmalloc_addr(E)
+ when any
+* \(kfree\|kfree_sensitive\|kvfree\)(E)@f
+
+@depends on patch exists@
+expression E;
+position a != alloc.vok;
+position f != free.fok;
+@@
+
+ E = \(vmalloc\|vzalloc\|vmalloc_user\|vmalloc_node\|vzalloc_node\|
+ vmalloc_exec\|vmalloc_32\|vmalloc_32_user\|__vmalloc\|
+ __vmalloc_node_range\|__vmalloc_node\)(...)@a
+ ... when != is_vmalloc_addr(E)
+ when any
+- \(kfree\|kvfree\)(E)@f
++ vfree(E)
+
+@kvfree depends on !patch@
+expression E;
+position a, f;
+@@
+
+* E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
+* kvmalloc_array\)(...)@a
+ ... when != is_vmalloc_addr(E)
+ when any
+* \(kfree\|kfree_sensitive\|vfree\|vfree_atomic\)(E)@f
+
+@depends on patch exists@
+expression E;
+@@
+
+ E = \(kvmalloc\|kvzalloc\|kvcalloc\|kvzalloc_node\|kvmalloc_node\|
+ kvmalloc_array\)(...)
+ ... when != is_vmalloc_addr(E)
+ when any
+- \(kfree\|vfree\)(E)
++ kvfree(E)
+
+@kvfree_switch depends on !patch@
+expression alloc.E;
+position f;
+@@
+
+ ... when != is_vmalloc_addr(E)
+ when any
+* \(kfree\|kfree_sensitive\|vfree\|vfree_atomic\)(E)@f
+
+@depends on patch exists@
+expression alloc.E;
+position f;
+@@
+
+ ... when != is_vmalloc_addr(E)
+ when any
+(
+- \(kfree\|vfree\)(E)@f
++ kvfree(E)
+|
+- kfree_sensitive(E)@f
++ kvfree_sensitive(E)
+)
+
+@script: python depends on report@
+a << vfree.a;
+f << vfree.f;
+@@
+
+msg = "WARNING kmalloc is used to allocate this memory at line %s" % (a[0].line)
+coccilib.report.print_report(f[0], msg)
+
+@script: python depends on org@
+a << vfree.a;
+f << vfree.f;
+@@
+
+msg = "WARNING kmalloc is used to allocate this memory at line %s" % (a[0].line)
+coccilib.org.print_todo(f[0], msg)
+
+@script: python depends on report@
+a << kfree.a;
+f << kfree.f;
+@@
+
+msg = "WARNING vmalloc is used to allocate this memory at line %s" % (a[0].line)
+coccilib.report.print_report(f[0], msg)
+
+@script: python depends on org@
+a << kfree.a;
+f << kfree.f;
+@@
+
+msg = "WARNING vmalloc is used to allocate this memory at line %s" % (a[0].line)
+coccilib.org.print_todo(f[0], msg)
+
+@script: python depends on report@
+a << kvfree.a;
+f << kvfree.f;
+@@
+
+msg = "WARNING kvmalloc is used to allocate this memory at line %s" % (a[0].line)
+coccilib.report.print_report(f[0], msg)
+
+@script: python depends on org@
+a << kvfree.a;
+f << kvfree.f;
+@@
+
+msg = "WARNING kvmalloc is used to allocate this memory at line %s" % (a[0].line)
+coccilib.org.print_todo(f[0], msg)
+
+@script: python depends on report@
+ka << alloc.kok;
+va << alloc.vok;
+f << kvfree_switch.f;
+@@
+
+msg = "WARNING kmalloc (line %s) && vmalloc (line %s) are used to allocate this memory" % (ka[0].line, va[0].line)
+coccilib.report.print_report(f[0], msg)
+
+@script: python depends on org@
+ka << alloc.kok;
+va << alloc.vok;
+f << kvfree_switch.f;
+@@
+
+msg = "WARNING kmalloc (line %s) && vmalloc (line %s) are used to allocate this memory" % (ka[0].line, va[0].line)
+coccilib.org.print_todo(f[0], msg)
+
--
2.26.2