Coccinelle: Add free/kfree.cocci

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

Signed-off-by: Nicolas Palix <npalix@diku.dk>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: Michal Marek <mmarek@suse.cz>
This commit is contained in:
Nicolas Palix 2010-08-24 17:39:04 +02:00 committed by Michal Marek
parent 5c34050188
commit 43ba21b57a

View File

@ -0,0 +1,116 @@
/// 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 Nicolas Palix, DIKU. GPLv2.
// Copyright: (C) 2010 Julia Lawall, DIKU. GPLv2.
// Copyright: (C) 2010 Gilles Muller, INRIA/LiP6. GPLv2.
// URL: http://coccinelle.lip6.fr/
// Comments:
// Options: -no_includes -include_headers
virtual org
virtual report
@free@
expression E;
position p1;
@@
kfree@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
|
!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)
... 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,...)
...
(
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 = "reference preceded by free on line %s" % (p1[0].line)
coccilib.report.print_report(p2[0],msg)