[PATCH v8] coccinelle: api: add kfree_mismatch script

[Denis Efremov]

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