linux-stable.git/drivers/staging/android, branch v3.18.136

staging: android: ion: fix ION_IOC_{MAP,SHARE} use-after-free

2018-10-13T07:09:28+00:00

commit 2c155709e4ef2d86d0176aac82e44c048a7e0255 upstream.

The ION_IOC_{MAP,SHARE} ioctls drop and reacquire client->lock several
times while operating on one of the client's ion_handles.  This creates
windows where userspace can call ION_IOC_FREE on the same client with
the same handle, and effectively make the kernel drop its own reference.
For example:

- thread A: ION_IOC_ALLOC creates an ion_handle with refcount 1
- thread A: starts ION_IOC_MAP and increments the refcount to 2
- thread B: ION_IOC_FREE decrements the refcount to 1
- thread B: ION_IOC_FREE decrements the refcount to 0 and frees the
            handle
- thread A: continues ION_IOC_MAP with a dangling ion_handle * to
            freed memory

Fix this by holding client->lock for the duration of
ION_IOC_{MAP,SHARE}, preventing the concurrent ION_IOC_FREE.  Also
remove ion_handle_get_by_id(), since there's literally no way to use it
safely.

This patch is applied on top of 4.4.y, and applies to older kernels
too.  4.9.y was fixed separately.  Kernels 4.12 and later are
unaffected, since all the underlying ion_handle infrastructure has been
ripped out.

Cc: stable@vger.kernel.org # v4.4-
Signed-off-by: Greg Hackmann 
Acked-by: Laura Abbott 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Greg Kroah-Hartman

staging: android: ashmem: Fix mmap size validation

2018-10-13T07:09:26+00:00

[ Upstream commit 8632c614565d0c5fdde527889601c018e97b6384 ]

The ashmem driver did not check that the size/offset of the vma passed
to its .mmap() function was not larger than the ashmem object being
mapped. This could cause mmap() to succeed, even though accessing parts
of the mapping would later fail with a segmentation fault.

Ensure an error is returned by the ashmem_mmap() function if the vma
size is larger than the ashmem object size. This enables safer handling
of the problem in userspace.

Cc: Todd Kjos 
Cc: devel@driverdev.osuosl.org
Cc: linux-kernel@vger.kernel.org
Cc: kernel-team@android.com
Cc: Joel Fernandes 
Signed-off-by: Alistair Strachan 
Acked-by: Joel Fernandes (Google) 
Reviewed-by: Martijn Coenen 
Signed-off-by: Greg Kroah-Hartman 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

staging: android: ion: check for kref overflow

2018-08-28T05:21:37+00:00

This patch is against 4.4. It does not apply to master due to a large
rework of ion in 4.12 which removed the affected functions altogther.
4c23cbff073f3b9b ("staging: android: ion: Remove import interface")

Userspace can cause the kref to handles to increment
arbitrarily high. Ensure it does not overflow.

Signed-off-by: Daniel Rosenberg 
Signed-off-by: Greg Kroah-Hartman

staging: android: ion: Return an ERR_PTR in ion_map_kernel

2018-07-11T13:42:24+00:00

commit 0a2bc00341dcfcc793c0dbf4f8d43adf60458b05 upstream.

The expected return value from ion_map_kernel is an ERR_PTR. The error
path for a vmalloc failure currently just returns NULL, triggering
a warning in ion_buffer_kmap_get. Encode the vmalloc failure as an ERR_PTR.

Reported-by: syzbot+55b1d9f811650de944c6@syzkaller.appspotmail.com
Signed-off-by: Laura Abbott 
Cc: stable 
Signed-off-by: Greg Kroah-Hartman

staging: android: ashmem: Fix lockdep issue during llseek

2018-03-18T10:15:44+00:00

commit cb57469c9573f6018cd1302953dd45d6e05aba7b upstream.

ashmem_mutex create a chain of dependencies like so:

(1)
mmap syscall ->
  mmap_sem ->  (acquired)
  ashmem_mmap
  ashmem_mutex (try to acquire)
  (block)

(2)
llseek syscall ->
  ashmem_llseek ->
  ashmem_mutex ->  (acquired)
  inode_lock ->
  inode->i_rwsem (try to acquire)
  (block)

(3)
getdents ->
  iterate_dir ->
  inode_lock ->
  inode->i_rwsem   (acquired)
  copy_to_user ->
  mmap_sem         (try to acquire)

There is a lock ordering created between mmap_sem and inode->i_rwsem
causing a lockdep splat [2] during a syzcaller test, this patch fixes
the issue by unlocking the mutex earlier. Functionally that's Ok since
we don't need to protect vfs_llseek.

[1] https://patchwork.kernel.org/patch/10185031/
[2] https://lkml.org/lkml/2018/1/10/48

Acked-by: Todd Kjos 
Cc: Arve Hjonnevag 
Cc: stable@vger.kernel.org
Reported-by: syzbot+8ec30bb7bf1a981a2012@syzkaller.appspotmail.com
Signed-off-by: Joel Fernandes 
Acked-by: Greg Hackmann 
Signed-off-by: Greg Kroah-Hartman

staging: android: ashmem: fix a race condition in ASHMEM_SET_SIZE ioctl

2018-01-17T08:29:31+00:00

commit 443064cb0b1fb4569fe0a71209da7625129fb760 upstream.

A lock-unlock is missing in ASHMEM_SET_SIZE ioctl which can result in a
race condition when mmap is called. After the !asma->file check, before
setting asma->size, asma->file can be set in mmap. That would result in
having different asma->size than the mapped memory size. Combined with
ASHMEM_UNPIN ioctl and shrinker invocation, this can result in memory
corruption.

Signed-off-by: Viktor Slavkovic 
Signed-off-by: Greg Kroah-Hartman

staging/android/ion : fix a race condition in the ion driver

2017-04-30T03:49:17+00:00

commit 9590232bb4f4cc824f3425a6e1349afbe6d6d2b7 upstream.

There is a use-after-free problem in the ion driver.
This is caused by a race condition in the ion_ioctl()
function.

A handle has ref count of 1 and two tasks on different
cpus calls ION_IOC_FREE simultaneously.

cpu 0                                   cpu 1
-------------------------------------------------------
ion_handle_get_by_id()
(ref == 2)
                            ion_handle_get_by_id()
                            (ref == 3)

ion_free()
(ref == 2)

ion_handle_put()
(ref == 1)

                            ion_free()
                            (ref == 0 so ion_handle_destroy() is
                            called
                            and the handle is freed.)

                            ion_handle_put() is called and it
                            decreases the slub's next free pointer

The problem is detected as an unaligned access in the
spin lock functions since it uses load exclusive
 instruction. In some cases it corrupts the slub's
free pointer which causes a mis-aligned access to the
next free pointer.(kmalloc returns a pointer like
ffffc0745b4580aa). And it causes lots of other
hard-to-debug problems.

This symptom is caused since the first member in the
ion_handle structure is the reference count and the
ion driver decrements the reference after it has been
freed.

To fix this problem client->lock mutex is extended
to protect all the codes that uses the handle.

Signed-off-by: Eun Taik Lee 
Reviewed-by: Laura Abbott 
Cc: Ben Hutchings 
Signed-off-by: Greg Kroah-Hartman 

index 7ff2a7ec871f..33b390e7ea31

staging: android: ashmem: lseek failed due to no FMODE_LSEEK.

2017-04-18T05:55:48+00:00

commit 97fbfef6bd597888485b653175fb846c6998b60c upstream.

vfs_llseek will check whether the file mode has
FMODE_LSEEK, no return failure. But ashmem can be
lseek, so add FMODE_LSEEK to ashmem file.

Comment From Greg Hackmann:
	ashmem_llseek() passes the llseek() call through to the backing
	shmem file.  91360b02ab48 ("ashmem: use vfs_llseek()") changed
	this from directly calling the file's llseek() op into a VFS
	layer call.  This also adds a check for the FMODE_LSEEK bit, so
	without that bit ashmem_llseek() now always fails with -ESPIPE.

Fixes: 91360b02ab48 ("ashmem: use vfs_llseek()")
Signed-off-by: Shuxiao Zhang 
Tested-by: Greg Hackmann 
Signed-off-by: Greg Kroah-Hartman

ANDROID: binder: Clear binder and cookie when setting handle in flat binder struct

2017-04-18T05:55:45+00:00

commit 4afb604e2d14d429ac9e1fd84b952602853b2df5 upstream.

Prevents leaking pointers between processes

Signed-off-by: Arve Hjønnevåg 
Signed-off-by: Martijn Coenen 
Signed-off-by: Greg Kroah-Hartman

ANDROID: binder: Add strong ref checks

2017-04-18T05:55:45+00:00

commit 0a3ffab93fe52530602fe47cd74802cffdb19c05 upstream.

Prevent using a binder_ref with only weak references where a strong
reference is required.

Signed-off-by: Arve Hjønnevåg 
Signed-off-by: Martijn Coenen 
Signed-off-by: Greg Kroah-Hartman