[PATCH] selinux: fix memory leak in sel_make_bools

[PATCH] selinux: fix memory leak in sel_make_bools

[Xiaotian Feng]

In sel_make_bools, kernel allocates memory for bool_pending_names[i]
with security_get_bools. So if we just free bool_pending_names, those
memories for bool_pending_names[i] will be leaked.

This patch resolves dozens of following kmemleak report after resuming
from suspend:
unreferenced object 0xffff88022e4c7380 (size 32):
  comm "init", pid 1, jiffies 4294677173
  backtrace:
    [<ffffffff810f76b5>] create_object+0x1a2/0x2a9
    [<ffffffff810f78bb>] kmemleak_alloc+0x26/0x4b
    [<ffffffff810ef3eb>] __kmalloc+0x18f/0x1b8
    [<ffffffff811cd511>] security_get_bools+0xd7/0x16f
    [<ffffffff811c48c0>] sel_write_load+0x12e/0x62b
    [<ffffffff810f9a39>] vfs_write+0xae/0x10b
    [<ffffffff810f9b56>] sys_write+0x4a/0x6e
    [<ffffffff81011b82>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
---
 security/selinux/selinuxfs.c |    6 +++++-
 1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index b4fc506..ab93472 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -979,7 +979,11 @@ static int sel_make_bools(void)
 	u32 sid;
 
 	/* remove any existing files */
-	kfree(bool_pending_names);
+	if (bool_pending_names) {
+		for (i = 0; i < bool_num; i++)
+			kfree(bool_pending_names[i]);
+		kfree(bool_pending_names);
+	}
 	kfree(bool_pending_values);
 	bool_pending_names = NULL;
 	bool_pending_values = NULL;
-- 
1.6.2.5

Re: [PATCH] selinux: fix memory leak in sel_make_bools

[Paul Moore]

On Thursday 13 August 2009 04:26:16 am Xiaotian Feng wrote:
> In sel_make_bools, kernel allocates memory for bool_pending_names[i]
> with security_get_bools. So if we just free bool_pending_names, those
> memories for bool_pending_names[i] will be leaked.
>
> This patch resolves dozens of following kmemleak report after resuming
> from suspend:
> unreferenced object 0xffff88022e4c7380 (size 32):
>   comm "init", pid 1, jiffies 4294677173
>   backtrace:
>     [<ffffffff810f76b5>] create_object+0x1a2/0x2a9
>     [<ffffffff810f78bb>] kmemleak_alloc+0x26/0x4b
>     [<ffffffff810ef3eb>] __kmalloc+0x18f/0x1b8
>     [<ffffffff811cd511>] security_get_bools+0xd7/0x16f
>     [<ffffffff811c48c0>] sel_write_load+0x12e/0x62b
>     [<ffffffff810f9a39>] vfs_write+0xae/0x10b
>     [<ffffffff810f9b56>] sys_write+0x4a/0x6e
>     [<ffffffff81011b82>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
>
> Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
> ---
>  security/selinux/selinuxfs.c |    6 +++++-
>  1 files changed, 5 insertions(+), 1 deletions(-)
>
> diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
> index b4fc506..ab93472 100644
> --- a/security/selinux/selinuxfs.c
> +++ b/security/selinux/selinuxfs.c
> @@ -979,7 +979,11 @@ static int sel_make_bools(void)
>  	u32 sid;
>
>  	/* remove any existing files */
> -	kfree(bool_pending_names);
> +	if (bool_pending_names) {
> +		for (i = 0; i < bool_num; i++)
> +			kfree(bool_pending_names[i]);
> +		kfree(bool_pending_names);
> +	}
>  	kfree(bool_pending_values);
>  	bool_pending_names = NULL;
>  	bool_pending_values = NULL;

Since the code seems to rely on 'bool_num' in other places to ensure we don't 
walk off the end of the array it is probably safe to omit the 'if 
(bool_pending_names) ...' conditional and just rely on the for loop to do the 
right thing.

-- 
paul moore
linux @ hp

Re: [PATCH] selinux: fix memory leak in sel_make_bools

[Danny Feng]

On 08/14/2009 02:55 AM, Paul Moore wrote:
> On Thursday 13 August 2009 04:26:16 am Xiaotian Feng wrote:
>> In sel_make_bools, kernel allocates memory for bool_pending_names[i]
>> with security_get_bools. So if we just free bool_pending_names, those
>> memories for bool_pending_names[i] will be leaked.
>>
>> This patch resolves dozens of following kmemleak report after resuming
>> from suspend:
>> unreferenced object 0xffff88022e4c7380 (size 32):
>>    comm "init", pid 1, jiffies 4294677173
>>    backtrace:
>>      [<ffffffff810f76b5>] create_object+0x1a2/0x2a9
>>      [<ffffffff810f78bb>] kmemleak_alloc+0x26/0x4b
>>      [<ffffffff810ef3eb>] __kmalloc+0x18f/0x1b8
>>      [<ffffffff811cd511>] security_get_bools+0xd7/0x16f
>>      [<ffffffff811c48c0>] sel_write_load+0x12e/0x62b
>>      [<ffffffff810f9a39>] vfs_write+0xae/0x10b
>>      [<ffffffff810f9b56>] sys_write+0x4a/0x6e
>>      [<ffffffff81011b82>] system_call_fastpath+0x16/0x1b
>>      [<ffffffffffffffff>] 0xffffffffffffffff
>>
>> Signed-off-by: Xiaotian Feng<dfeng@redhat.com>
>> ---
>>   security/selinux/selinuxfs.c |    6 +++++-
>>   1 files changed, 5 insertions(+), 1 deletions(-)
>>
>> diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
>> index b4fc506..ab93472 100644
>> --- a/security/selinux/selinuxfs.c
>> +++ b/security/selinux/selinuxfs.c
>> @@ -979,7 +979,11 @@ static int sel_make_bools(void)
>>   	u32 sid;
>>
>>   	/* remove any existing files */
>> -	kfree(bool_pending_names);
>> +	if (bool_pending_names) {
>> +		for (i = 0; i<  bool_num; i++)
>> +			kfree(bool_pending_names[i]);
>> +		kfree(bool_pending_names);
>> +	}
>>   	kfree(bool_pending_values);
>>   	bool_pending_names = NULL;
>>   	bool_pending_values = NULL;
>
> Since the code seems to rely on 'bool_num' in other places to ensure we don't
> walk off the end of the array it is probably safe to omit the 'if
> (bool_pending_names) ...' conditional and just rely on the for loop to do the
> right thing.
Thanks for point out, I'll resend V2 patch :-)

[PATCH V2] selinux: fix memory leak in sel_make_bools

[Xiaotian Feng]

In sel_make_bools, kernel allocates memory for bool_pending_names[i]
with security_get_bools. So if we just free bool_pending_names, those
memories for bool_pending_names[i] will be leaked.

This patch resolves dozens of following kmemleak report after resuming
from suspend:
unreferenced object 0xffff88022e4c7380 (size 32):
  comm "init", pid 1, jiffies 4294677173
  backtrace:
    [<ffffffff810f76b5>] create_object+0x1a2/0x2a9
    [<ffffffff810f78bb>] kmemleak_alloc+0x26/0x4b
    [<ffffffff810ef3eb>] __kmalloc+0x18f/0x1b8
    [<ffffffff811cd511>] security_get_bools+0xd7/0x16f
    [<ffffffff811c48c0>] sel_write_load+0x12e/0x62b
    [<ffffffff810f9a39>] vfs_write+0xae/0x10b
    [<ffffffff810f9b56>] sys_write+0x4a/0x6e
    [<ffffffff81011b82>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff

Signed-off-by: Xiaotian Feng <dfeng@redhat.com>
---
 security/selinux/selinuxfs.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
index b4fc506..1a8a1c2 100644
--- a/security/selinux/selinuxfs.c
+++ b/security/selinux/selinuxfs.c
@@ -979,6 +979,8 @@ static int sel_make_bools(void)
 	u32 sid;
 
 	/* remove any existing files */
+	for (i = 0; i < bool_num; i++)
+		kfree(bool_pending_names[i]);
 	kfree(bool_pending_names);
 	kfree(bool_pending_values);
 	bool_pending_names = NULL;
-- 
1.6.2.5

Re: [PATCH V2] selinux: fix memory leak in sel_make_bools

[Serge E. Hallyn]

Quoting Xiaotian Feng (dfeng@redhat.com):
> In sel_make_bools, kernel allocates memory for bool_pending_names[i]
> with security_get_bools. So if we just free bool_pending_names, those
> memories for bool_pending_names[i] will be leaked.
> 
> This patch resolves dozens of following kmemleak report after resuming
> from suspend:
> unreferenced object 0xffff88022e4c7380 (size 32):
>   comm "init", pid 1, jiffies 4294677173
>   backtrace:
>     [<ffffffff810f76b5>] create_object+0x1a2/0x2a9
>     [<ffffffff810f78bb>] kmemleak_alloc+0x26/0x4b
>     [<ffffffff810ef3eb>] __kmalloc+0x18f/0x1b8
>     [<ffffffff811cd511>] security_get_bools+0xd7/0x16f
>     [<ffffffff811c48c0>] sel_write_load+0x12e/0x62b
>     [<ffffffff810f9a39>] vfs_write+0xae/0x10b
>     [<ffffffff810f9b56>] sys_write+0x4a/0x6e
>     [<ffffffff81011b82>] system_call_fastpath+0x16/0x1b
>     [<ffffffffffffffff>] 0xffffffffffffffff
> 
> Signed-off-by: Xiaotian Feng <dfeng@redhat.com>

Acked-by: Serge Hallyn <serue@us.ibm.com>

> ---
>  security/selinux/selinuxfs.c |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/security/selinux/selinuxfs.c b/security/selinux/selinuxfs.c
> index b4fc506..1a8a1c2 100644
> --- a/security/selinux/selinuxfs.c
> +++ b/security/selinux/selinuxfs.c
> @@ -979,6 +979,8 @@ static int sel_make_bools(void)
>  	u32 sid;
> 
>  	/* remove any existing files */
> +	for (i = 0; i < bool_num; i++)
> +		kfree(bool_pending_names[i]);
>  	kfree(bool_pending_names);
>  	kfree(bool_pending_values);
>  	bool_pending_names = NULL;
> -- 
> 1.6.2.5

Re: [PATCH V2] selinux: fix memory leak in sel_make_bools

[James Morris]

On Fri, 14 Aug 2009, Xiaotian Feng wrote:

> In sel_make_bools, kernel allocates memory for bool_pending_names[i]
> with security_get_bools. So if we just free bool_pending_names, those
> memories for bool_pending_names[i] will be leaked.

Thanks, applied and pushed to Linus.

-- 
James Morris
<jmorris@namei.org>

Re: [PATCH V2] selinux: fix memory leak in sel_make_bools

[Xiaotian Feng]

On 08/14/2009 02:06 PM, James Morris wrote:
> On Fri, 14 Aug 2009, Xiaotian Feng wrote:
>
>> In sel_make_bools, kernel allocates memory for bool_pending_names[i]
>> with security_get_bools. So if we just free bool_pending_names, those
>> memories for bool_pending_names[i] will be leaked.
>
> Thanks, applied and pushed to Linus.
This patch is missing or dropped? I'm not seeing this patch until 
2.6.33-rc7, thanks.

Re: [PATCH V2] selinux: fix memory leak in sel_make_bools

[James Morris]

On Mon, 8 Feb 2010, Xiaotian Feng wrote:

> On 08/14/2009 02:06 PM, James Morris wrote:
> > On Fri, 14 Aug 2009, Xiaotian Feng wrote:
> > 
> > > In sel_make_bools, kernel allocates memory for bool_pending_names[i]
> > > with security_get_bools. So if we just free bool_pending_names, those
> > > memories for bool_pending_names[i] will be leaked.
> > 
> > Thanks, applied and pushed to Linus.
> This patch is missing or dropped? I'm not seeing this patch until 2.6.33-rc7,
> thanks.

Not sure what happened to that -- I pushed it to Linus, but it's not in 
the tree for some reason.  Now applied to

git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6#next


-- 
James Morris
<jmorris@namei.org>