* [PATCH v2] tools: Fix use-after-free for realloc(..., 0)
@ 2022-02-13 18:24 Kees Cook
2022-02-14 20:07 ` Josh Poimboeuf
2022-02-15 20:58 ` Justin Forbes
0 siblings, 2 replies; 5+ messages in thread
From: Kees Cook @ 2022-02-13 18:24 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: Kees Cook, Valdis Klētnieks, Arnaldo Carvalho de Melo,
Justin Forbes, linux-kernel, linux-hardening
GCC 12 was correctly reporting a potential use-after-free condition in
the xrealloc helper. Fix the warning by avoiding an implicit "free(ptr)"
when size == 0:
In file included from help.c:12:
In function 'xrealloc',
inlined from 'add_cmdname' at help.c:24:2: subcmd-util.h:56:23: error: pointer may be used after 'realloc' [-Werror=use-after-free]
56 | ret = realloc(ptr, size);
| ^~~~~~~~~~~~~~~~~~
subcmd-util.h:52:21: note: call to 'realloc' here
52 | void *ret = realloc(ptr, size);
| ^~~~~~~~~~~~~~~~~~
subcmd-util.h:58:31: error: pointer may be used after 'realloc' [-Werror=use-after-free]
58 | ret = realloc(ptr, 1);
| ^~~~~~~~~~~~~~~
subcmd-util.h:52:21: note: call to 'realloc' here
52 | void *ret = realloc(ptr, size);
| ^~~~~~~~~~~~~~~~~~
Reported-by: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
Fixes: 2f4ce5ec1d44 ("perf tools: Finalize subcmd independence")
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
---
v1: https://lore.kernel.org/lkml/20220212181855.3460176-1-keescook@chromium.org/
v2: simplify logic (josh)
---
tools/lib/subcmd/subcmd-util.h | 11 ++---------
1 file changed, 2 insertions(+), 9 deletions(-)
diff --git a/tools/lib/subcmd/subcmd-util.h b/tools/lib/subcmd/subcmd-util.h
index 794a375dad36..b2aec04fce8f 100644
--- a/tools/lib/subcmd/subcmd-util.h
+++ b/tools/lib/subcmd/subcmd-util.h
@@ -50,15 +50,8 @@ static NORETURN inline void die(const char *err, ...)
static inline void *xrealloc(void *ptr, size_t size)
{
void *ret = realloc(ptr, size);
- if (!ret && !size)
- ret = realloc(ptr, 1);
- if (!ret) {
- ret = realloc(ptr, size);
- if (!ret && !size)
- ret = realloc(ptr, 1);
- if (!ret)
- die("Out of memory, realloc failed");
- }
+ if (!ret)
+ die("Out of memory, realloc failed");
return ret;
}
--
2.30.2
^ permalink raw reply related [flat|nested] 5+ messages in thread* Re: [PATCH v2] tools: Fix use-after-free for realloc(..., 0)
2022-02-13 18:24 [PATCH v2] tools: Fix use-after-free for realloc(..., 0) Kees Cook
@ 2022-02-14 20:07 ` Josh Poimboeuf
2022-02-15 20:42 ` Arnaldo Carvalho de Melo
2022-02-15 20:58 ` Justin Forbes
1 sibling, 1 reply; 5+ messages in thread
From: Josh Poimboeuf @ 2022-02-14 20:07 UTC (permalink / raw)
To: Kees Cook
Cc: Valdis Klētnieks, Arnaldo Carvalho de Melo, Justin Forbes,
linux-kernel, linux-hardening
On Sun, Feb 13, 2022 at 10:24:43AM -0800, Kees Cook wrote:
> GCC 12 was correctly reporting a potential use-after-free condition in
> the xrealloc helper. Fix the warning by avoiding an implicit "free(ptr)"
> when size == 0:
>
> In file included from help.c:12:
> In function 'xrealloc',
> inlined from 'add_cmdname' at help.c:24:2: subcmd-util.h:56:23: error: pointer may be used after 'realloc' [-Werror=use-after-free]
> 56 | ret = realloc(ptr, size);
> | ^~~~~~~~~~~~~~~~~~
> subcmd-util.h:52:21: note: call to 'realloc' here
> 52 | void *ret = realloc(ptr, size);
> | ^~~~~~~~~~~~~~~~~~
> subcmd-util.h:58:31: error: pointer may be used after 'realloc' [-Werror=use-after-free]
> 58 | ret = realloc(ptr, 1);
> | ^~~~~~~~~~~~~~~
> subcmd-util.h:52:21: note: call to 'realloc' here
> 52 | void *ret = realloc(ptr, size);
> | ^~~~~~~~~~~~~~~~~~
>
> Reported-by: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
> Fixes: 2f4ce5ec1d44 ("perf tools: Finalize subcmd independence")
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
> ---
> v1: https://lore.kernel.org/lkml/20220212181855.3460176-1-keescook@chromium.org/
> v2: simplify logic (josh)
Thanks, running through testing now.
--
Josh
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2] tools: Fix use-after-free for realloc(..., 0)
2022-02-14 20:07 ` Josh Poimboeuf
@ 2022-02-15 20:42 ` Arnaldo Carvalho de Melo
2022-02-15 22:14 ` Josh Poimboeuf
0 siblings, 1 reply; 5+ messages in thread
From: Arnaldo Carvalho de Melo @ 2022-02-15 20:42 UTC (permalink / raw)
To: Josh Poimboeuf
Cc: Kees Cook, Valdis Klētnieks, Arnaldo Carvalho de Melo,
Justin Forbes, linux-kernel, linux-hardening
Em Mon, Feb 14, 2022 at 12:07:30PM -0800, Josh Poimboeuf escreveu:
> On Sun, Feb 13, 2022 at 10:24:43AM -0800, Kees Cook wrote:
> > GCC 12 was correctly reporting a potential use-after-free condition in
> > the xrealloc helper. Fix the warning by avoiding an implicit "free(ptr)"
> > when size == 0:
> >
> > In file included from help.c:12:
> > In function 'xrealloc',
> > inlined from 'add_cmdname' at help.c:24:2: subcmd-util.h:56:23: error: pointer may be used after 'realloc' [-Werror=use-after-free]
> > 56 | ret = realloc(ptr, size);
> > | ^~~~~~~~~~~~~~~~~~
> > subcmd-util.h:52:21: note: call to 'realloc' here
> > 52 | void *ret = realloc(ptr, size);
> > | ^~~~~~~~~~~~~~~~~~
> > subcmd-util.h:58:31: error: pointer may be used after 'realloc' [-Werror=use-after-free]
> > 58 | ret = realloc(ptr, 1);
> > | ^~~~~~~~~~~~~~~
> > subcmd-util.h:52:21: note: call to 'realloc' here
> > 52 | void *ret = realloc(ptr, size);
> > | ^~~~~~~~~~~~~~~~~~
> >
> > Reported-by: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
> > Fixes: 2f4ce5ec1d44 ("perf tools: Finalize subcmd independence")
> > Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> > Signed-off-by: Kees Cook <keescook@chromium.org>
> > ---
> > v1: https://lore.kernel.org/lkml/20220212181855.3460176-1-keescook@chromium.org/
> > v2: simplify logic (josh)
>
> Thanks, running through testing now.
I assume that testing went ok, may I add a Tested-by: you?
- Arnaldo
^ permalink raw reply [flat|nested] 5+ messages in thread* Re: [PATCH v2] tools: Fix use-after-free for realloc(..., 0)
2022-02-15 20:42 ` Arnaldo Carvalho de Melo
@ 2022-02-15 22:14 ` Josh Poimboeuf
0 siblings, 0 replies; 5+ messages in thread
From: Josh Poimboeuf @ 2022-02-15 22:14 UTC (permalink / raw)
To: Arnaldo Carvalho de Melo
Cc: Kees Cook, Valdis Klētnieks, Arnaldo Carvalho de Melo,
Justin Forbes, linux-kernel, linux-hardening
On Tue, Feb 15, 2022 at 05:42:35PM -0300, Arnaldo Carvalho de Melo wrote:
> Em Mon, Feb 14, 2022 at 12:07:30PM -0800, Josh Poimboeuf escreveu:
> > On Sun, Feb 13, 2022 at 10:24:43AM -0800, Kees Cook wrote:
> > > GCC 12 was correctly reporting a potential use-after-free condition in
> > > the xrealloc helper. Fix the warning by avoiding an implicit "free(ptr)"
> > > when size == 0:
> > >
> > > In file included from help.c:12:
> > > In function 'xrealloc',
> > > inlined from 'add_cmdname' at help.c:24:2: subcmd-util.h:56:23: error: pointer may be used after 'realloc' [-Werror=use-after-free]
> > > 56 | ret = realloc(ptr, size);
> > > | ^~~~~~~~~~~~~~~~~~
> > > subcmd-util.h:52:21: note: call to 'realloc' here
> > > 52 | void *ret = realloc(ptr, size);
> > > | ^~~~~~~~~~~~~~~~~~
> > > subcmd-util.h:58:31: error: pointer may be used after 'realloc' [-Werror=use-after-free]
> > > 58 | ret = realloc(ptr, 1);
> > > | ^~~~~~~~~~~~~~~
> > > subcmd-util.h:52:21: note: call to 'realloc' here
> > > 52 | void *ret = realloc(ptr, size);
> > > | ^~~~~~~~~~~~~~~~~~
> > >
> > > Reported-by: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
> > > Fixes: 2f4ce5ec1d44 ("perf tools: Finalize subcmd independence")
> > > Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> > > Signed-off-by: Kees Cook <keescook@chromium.org>
> > > ---
> > > v1: https://lore.kernel.org/lkml/20220212181855.3460176-1-keescook@chromium.org/
> > > v2: simplify logic (josh)
> >
> > Thanks, running through testing now.
>
> I assume that testing went ok, may I add a Tested-by: you?
Yes, feel free to add:
Acked-by: Josh Poimboeuf <jpoimboe@redhat.com>
--
Josh
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v2] tools: Fix use-after-free for realloc(..., 0)
2022-02-13 18:24 [PATCH v2] tools: Fix use-after-free for realloc(..., 0) Kees Cook
2022-02-14 20:07 ` Josh Poimboeuf
@ 2022-02-15 20:58 ` Justin Forbes
1 sibling, 0 replies; 5+ messages in thread
From: Justin Forbes @ 2022-02-15 20:58 UTC (permalink / raw)
To: Kees Cook
Cc: Josh Poimboeuf, Valdis Klētnieks, Arnaldo Carvalho de Melo,
linux-kernel, linux-hardening
On Sun, Feb 13, 2022 at 10:24:43AM -0800, Kees Cook wrote:
> GCC 12 was correctly reporting a potential use-after-free condition in
> the xrealloc helper. Fix the warning by avoiding an implicit "free(ptr)"
> when size == 0:
>
> In file included from help.c:12:
> In function 'xrealloc',
> inlined from 'add_cmdname' at help.c:24:2: subcmd-util.h:56:23: error: pointer may be used after 'realloc' [-Werror=use-after-free]
> 56 | ret = realloc(ptr, size);
> | ^~~~~~~~~~~~~~~~~~
> subcmd-util.h:52:21: note: call to 'realloc' here
> 52 | void *ret = realloc(ptr, size);
> | ^~~~~~~~~~~~~~~~~~
> subcmd-util.h:58:31: error: pointer may be used after 'realloc' [-Werror=use-after-free]
> 58 | ret = realloc(ptr, 1);
> | ^~~~~~~~~~~~~~~
> subcmd-util.h:52:21: note: call to 'realloc' here
> 52 | void *ret = realloc(ptr, size);
> | ^~~~~~~~~~~~~~~~~~
>
> Reported-by: "Valdis Klētnieks" <valdis.kletnieks@vt.edu>
> Fixes: 2f4ce5ec1d44 ("perf tools: Finalize subcmd independence")
> Cc: Josh Poimboeuf <jpoimboe@redhat.com>
> Signed-off-by: Kees Cook <keescook@chromium.org>
Tested this patch with the Fedora rawhide builds, and this does indeed
fix the issue.
Tested-by: Justin M. Forbes <jforbes@fedoraproject.org>
^ permalink raw reply [flat|nested] 5+ messages in thread
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2022-02-13 18:24 [PATCH v2] tools: Fix use-after-free for realloc(..., 0) Kees Cook
2022-02-14 20:07 ` Josh Poimboeuf
2022-02-15 20:42 ` Arnaldo Carvalho de Melo
2022-02-15 22:14 ` Josh Poimboeuf
2022-02-15 20:58 ` Justin Forbes
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