[PATCH] sysfs: Don't leak secdata when a sysfs_dirent is freed.

[Eric W. Biederman]

While refreshing my sysfs patches I noticed a leak in the secdata
implementation.  We don't free the secdata when we free the
sysfs dirent.

This is a bug in 2.6.32-rc5 that we really should close.

Signed-off-by: Eric W. Biederman <ebiederm@...>
---

 fs/sysfs/dir.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 5fad489..e020183 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -21,6 +21,7 @@
 #include <linux/completion.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/security.h>
 #include "sysfs.h"
 
 DEFINE_MUTEX(sysfs_mutex);
@@ -285,6 +286,9 @@ void release_sysfs_dirent(struct sysfs_dirent * sd)
  sysfs_put(sd->s_symlink.target_sd);
  if (sysfs_type(sd) & SYSFS_COPY_NAME)
  kfree(sd->s_name);
+ if (sd->s_iattr && sd->s_iattr->ia_secdata)
+ security_release_secctx(sd->s_iattr->ia_secdata,
+ sd->s_iattr->ia_secdata_len);
  kfree(sd->s_iattr);
  sysfs_free_ino(sd->s_ino);
  kmem_cache_free(sysfs_dir_cachep, sd);
--
1.6.5.2.143.g8cc62

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Serge E. Hallyn]

Quoting Eric W. Biederman (ebiederm@...):
>
> While refreshing my sysfs patches I noticed a leak in the secdata
> implementation.  We don't free the secdata when we free the
> sysfs dirent.
>
> This is a bug in 2.6.32-rc5 that we really should close.
>
> Signed-off-by: Eric W. Biederman <ebiederm@...>

I'm surprised no kmemleak or anything has found this - but I guess
not many sites hand-set custom selinux contexts on sysfs?

Acked-by: Serge Hallyn <serue@...>

> ---
>
>  fs/sysfs/dir.c |    4 ++++
>  1 files changed, 4 insertions(+), 0 deletions(-)
>
> diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
> index 5fad489..e020183 100644
> --- a/fs/sysfs/dir.c
> +++ b/fs/sysfs/dir.c
> @@ -21,6 +21,7 @@
>  #include <linux/completion.h>
>  #include <linux/mutex.h>
>  #include <linux/slab.h>
> +#include <linux/security.h>
>  #include "sysfs.h"
>
>  DEFINE_MUTEX(sysfs_mutex);
> @@ -285,6 +286,9 @@ void release_sysfs_dirent(struct sysfs_dirent * sd)
>   sysfs_put(sd->s_symlink.target_sd);
>   if (sysfs_type(sd) & SYSFS_COPY_NAME)
>   kfree(sd->s_name);
> + if (sd->s_iattr && sd->s_iattr->ia_secdata)
> + security_release_secctx(sd->s_iattr->ia_secdata,
> + sd->s_iattr->ia_secdata_len);
>   kfree(sd->s_iattr);
>   sysfs_free_ino(sd->s_ino);
>   kmem_cache_free(sysfs_dir_cachep, sd);
> --
> 1.6.5.2.143.g8cc62
>
> --
> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
> the body of a message to majordomo@...
> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[Eric W. Biederman]

"Serge E. Hallyn" <serue@...> writes:

> Quoting Eric W. Biederman (ebiederm@...):
>>
>> While refreshing my sysfs patches I noticed a leak in the secdata
>> implementation.  We don't free the secdata when we free the
>> sysfs dirent.
>>
>> This is a bug in 2.6.32-rc5 that we really should close.
>>
>> Signed-off-by: Eric W. Biederman <ebiederm@...>
>
> I'm surprised no kmemleak or anything has found this - but I guess
> not many sites hand-set custom selinux contexts on sysfs?

I don't expect so since you couldn't customize it in 2.6.31.
This is brand new code, and this corner case was just overlooked
in the review.

Eric

> Acked-by: Serge Hallyn <serue@...>
>
>> ---
>>
>>  fs/sysfs/dir.c |    4 ++++
>>  1 files changed, 4 insertions(+), 0 deletions(-)
>>
>> diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
>> index 5fad489..e020183 100644
>> --- a/fs/sysfs/dir.c
>> +++ b/fs/sysfs/dir.c
>> @@ -21,6 +21,7 @@
>>  #include <linux/completion.h>
>>  #include <linux/mutex.h>
>>  #include <linux/slab.h>
>> +#include <linux/security.h>
>>  #include "sysfs.h"
>>
>>  DEFINE_MUTEX(sysfs_mutex);
>> @@ -285,6 +286,9 @@ void release_sysfs_dirent(struct sysfs_dirent * sd)
>>   sysfs_put(sd->s_symlink.target_sd);
>>   if (sysfs_type(sd) & SYSFS_COPY_NAME)
>>   kfree(sd->s_name);
>> + if (sd->s_iattr && sd->s_iattr->ia_secdata)
>> + security_release_secctx(sd->s_iattr->ia_secdata,
>> + sd->s_iattr->ia_secdata_len);
>>   kfree(sd->s_iattr);
>>   sysfs_free_ino(sd->s_ino);
>>   kmem_cache_free(sysfs_dir_cachep, sd);
>> --
>> 1.6.5.2.143.g8cc62
>>
>> --
>> To unsubscribe from this list: send the line "unsubscribe linux-security-module" in
>> the body of a message to majordomo@...
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

[James Morris-2]

Hi Linus,

This fixes a memory leak introduced in 2.6.32-rc5, please pull.


The following changes since commit 91d3f9bacdb4950d2f79fe2ba296aa249f60d06c:
  Linus Torvalds (1):
        Merge branch 'for-linus' of git://git.kernel.org/.../anholt/drm-intel

are available in the git repository at:

  git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6 for-linus

Eric W. Biederman (1):
      sysfs: Don't leak secdata when a sysfs_dirent is freed.

 fs/sysfs/dir.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)


--
James Morris
<jmorris@...>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/