* [PATCH 0/1] selinux: fix double free
@ 2020-06-10 18:10 trix
2020-06-10 18:10 ` [PATCH 1/1] " trix
0 siblings, 1 reply; 4+ messages in thread
From: trix @ 2020-06-10 18:10 UTC (permalink / raw)
To: paul, stephen.smalley.work, eparis, omosnace, jeffv, rgb
Cc: selinux, linux-kernel, Tom Rix
From: Tom Rix <trix@redhat.com>
Repo: linux-next
Tag: next-20200609
Running clang scan-view over linux-next uncovers many problem only a
few are memory related, this one looked like the most serious.
Tom Rix (1):
selinux: fix double free
security/selinux/ss/services.c | 4 ++++
1 file changed, 4 insertions(+)
--
2.18.1
^ permalink raw reply [flat|nested] 4+ messages in thread
* [PATCH 1/1] selinux: fix double free
2020-06-10 18:10 [PATCH 0/1] selinux: fix double free trix
@ 2020-06-10 18:10 ` trix
2020-06-10 19:10 ` Stephen Smalley
0 siblings, 1 reply; 4+ messages in thread
From: trix @ 2020-06-10 18:10 UTC (permalink / raw)
To: paul, stephen.smalley.work, eparis, omosnace, jeffv, rgb
Cc: selinux, linux-kernel, Tom Rix
From: Tom Rix <trix@redhat.com>
Clang's static analysis tool reports these double free memory errors.
security/selinux/ss/services.c:2987:4: warning: Attempt to free released memory [unix.Malloc]
kfree(bnames[i]);
^~~~~~~~~~~~~~~~
security/selinux/ss/services.c:2990:2: warning: Attempt to free released memory [unix.Malloc]
kfree(bvalues);
^~~~~~~~~~~~~~
So improve the security_get_bools error handling by freeing these variables
and setting their return pointers to NULL and the return len to 0
Signed-off-by: Tom Rix <trix@redhat.com>
---
security/selinux/ss/services.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
index 313919bd42f8..2dffae1feaff 100644
--- a/security/selinux/ss/services.c
+++ b/security/selinux/ss/services.c
@@ -2888,8 +2888,12 @@ int security_get_bools(struct selinux_state *state,
if (*names) {
for (i = 0; i < *len; i++)
kfree((*names)[i]);
+ kfree(names);
}
kfree(*values);
+ *len = 0;
+ *names = NULL;
+ *values = NULL;
goto out;
}
--
2.18.1
^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH 1/1] selinux: fix double free
2020-06-10 18:10 ` [PATCH 1/1] " trix
@ 2020-06-10 19:10 ` Stephen Smalley
2020-06-10 20:00 ` Tom Rix
0 siblings, 1 reply; 4+ messages in thread
From: Stephen Smalley @ 2020-06-10 19:10 UTC (permalink / raw)
To: trix
Cc: Paul Moore, Eric Paris, Ondrej Mosnacek, Jeffrey Vander Stoep,
rgb, SElinux list, linux-kernel
On Wed, Jun 10, 2020 at 2:10 PM <trix@redhat.com> wrote:
>
> From: Tom Rix <trix@redhat.com>
>
> Clang's static analysis tool reports these double free memory errors.
>
> security/selinux/ss/services.c:2987:4: warning: Attempt to free released memory [unix.Malloc]
> kfree(bnames[i]);
> ^~~~~~~~~~~~~~~~
> security/selinux/ss/services.c:2990:2: warning: Attempt to free released memory [unix.Malloc]
> kfree(bvalues);
> ^~~~~~~~~~~~~~
>
> So improve the security_get_bools error handling by freeing these variables
> and setting their return pointers to NULL and the return len to 0
>
> Signed-off-by: Tom Rix <trix@redhat.com>
> ---
> security/selinux/ss/services.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/security/selinux/ss/services.c b/security/selinux/ss/services.c
> index 313919bd42f8..2dffae1feaff 100644
> --- a/security/selinux/ss/services.c
> +++ b/security/selinux/ss/services.c
> @@ -2888,8 +2888,12 @@ int security_get_bools(struct selinux_state *state,
> if (*names) {
> for (i = 0; i < *len; i++)
> kfree((*names)[i]);
> + kfree(names);
kfree(*names)?
> }
> kfree(*values);
> + *len = 0;
> + *names = NULL;
> + *values = NULL;
> goto out;
> }
Wondering if the caller handling ought to be changed too even though
this should avoid the problem.
^ permalink raw reply [flat|nested] 4+ messages in thread* Re: [PATCH 1/1] selinux: fix double free
2020-06-10 19:10 ` Stephen Smalley
@ 2020-06-10 20:00 ` Tom Rix
0 siblings, 0 replies; 4+ messages in thread
From: Tom Rix @ 2020-06-10 20:00 UTC (permalink / raw)
To: Stephen Smalley
Cc: Paul Moore, Eric Paris, Ondrej Mosnacek, Jeffrey Vander Stoep,
rgb, SElinux list, linux-kernel
>> +++ b/security/selinux/ss/services.c
>> @@ -2888,8 +2888,12 @@ int security_get_bools(struct selinux_state *state,
>> if (*names) {
>> for (i = 0; i < *len; i++)
>> kfree((*names)[i]);
>> + kfree(names);
> kfree(*names)?
Yes.
> kfree(*values);
>> + *len = 0;
>> + *names = NULL;
>> + *values = NULL;
>> goto out;
>> }
> Wondering if the caller handling ought to be changed too even though
> this should avoid the problem.
>
The poisoning of the returns avoids this.
^ permalink raw reply [flat|nested] 4+ messages in thread
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2020-06-10 18:10 [PATCH 0/1] selinux: fix double free trix
2020-06-10 18:10 ` [PATCH 1/1] " trix
2020-06-10 19:10 ` Stephen Smalley
2020-06-10 20:00 ` Tom Rix
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