This is a note to let you know that I've just added the patch titled ion: Fix use after free during ION_IOC_ALLOC to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: ion-fix-use-after-free-during-ion_ioc_alloc.patch and it can be found in the queue-4.9 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From foo@baz Thu Jan 27 04:37:00 PM CET 2022 From: Lee Jones <lee.jones@xxxxxxxxxx> Date: Tue, 25 Jan 2022 14:18:06 +0000 Subject: ion: Fix use after free during ION_IOC_ALLOC To: lee.jones@xxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx, Daniel Rosenberg <drosen@xxxxxxxxxx>, Dennis Cagle <d-cagle@xxxxxxxxxxxxxx>, Patrick Daly <pdaly@xxxxxxxxxxxxxx> Message-ID: <20220125141808.1172511-1-lee.jones@xxxxxxxxxx> From: Daniel Rosenberg <drosen@xxxxxxxxxx> If a user happens to call ION_IOC_FREE during an ION_IOC_ALLOC on the just allocated id, and the copy_to_user fails, the cleanup code will attempt to free an already freed handle. This adds a wrapper for ion_alloc that adds an ion_handle_get to avoid this. Signed-off-by: Daniel Rosenberg <drosen@xxxxxxxxxx> Signed-off-by: Dennis Cagle <d-cagle@xxxxxxxxxxxxxx> Signed-off-by: Patrick Daly <pdaly@xxxxxxxxxxxxxx> Signed-off-by: Lee Jones <lee.jones@xxxxxxxxxx> Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/staging/android/ion/ion-ioctl.c | 14 +++++++++----- drivers/staging/android/ion/ion.c | 15 ++++++++++++--- drivers/staging/android/ion/ion.h | 4 ++++ 3 files changed, 25 insertions(+), 8 deletions(-) --- a/drivers/staging/android/ion/ion-ioctl.c +++ b/drivers/staging/android/ion/ion-ioctl.c @@ -96,10 +96,10 @@ long ion_ioctl(struct file *filp, unsign { struct ion_handle *handle; - handle = ion_alloc(client, data.allocation.len, - data.allocation.align, - data.allocation.heap_id_mask, - data.allocation.flags); + handle = __ion_alloc(client, data.allocation.len, + data.allocation.align, + data.allocation.heap_id_mask, + data.allocation.flags, true); if (IS_ERR(handle)) return PTR_ERR(handle); @@ -174,10 +174,14 @@ long ion_ioctl(struct file *filp, unsign if (dir & _IOC_READ) { if (copy_to_user((void __user *)arg, &data, _IOC_SIZE(cmd))) { - if (cleanup_handle) + if (cleanup_handle) { ion_free(client, cleanup_handle); + ion_handle_put(cleanup_handle); + } return -EFAULT; } } + if (cleanup_handle) + ion_handle_put(cleanup_handle); return ret; } --- a/drivers/staging/android/ion/ion.c +++ b/drivers/staging/android/ion/ion.c @@ -401,9 +401,9 @@ static int ion_handle_add(struct ion_cli return 0; } -struct ion_handle *ion_alloc(struct ion_client *client, size_t len, - size_t align, unsigned int heap_id_mask, - unsigned int flags) +struct ion_handle *__ion_alloc(struct ion_client *client, size_t len, + size_t align, unsigned int heap_id_mask, + unsigned int flags, bool grab_handle) { struct ion_handle *handle; struct ion_device *dev = client->dev; @@ -453,6 +453,8 @@ struct ion_handle *ion_alloc(struct ion_ return handle; mutex_lock(&client->lock); + if (grab_handle) + ion_handle_get(handle); ret = ion_handle_add(client, handle); mutex_unlock(&client->lock); if (ret) { @@ -462,6 +464,13 @@ struct ion_handle *ion_alloc(struct ion_ return handle; } + +struct ion_handle *ion_alloc(struct ion_client *client, size_t len, + size_t align, unsigned int heap_id_mask, + unsigned int flags) +{ + return __ion_alloc(client, len, align, heap_id_mask, flags, false); +} EXPORT_SYMBOL(ion_alloc); void ion_free_nolock(struct ion_client *client, --- a/drivers/staging/android/ion/ion.h +++ b/drivers/staging/android/ion/ion.h @@ -109,6 +109,10 @@ struct ion_handle *ion_alloc(struct ion_ size_t align, unsigned int heap_id_mask, unsigned int flags); +struct ion_handle *__ion_alloc(struct ion_client *client, size_t len, + size_t align, unsigned int heap_id_mask, + unsigned int flags, bool grab_handle); + /** * ion_free - free a handle * @client: the client Patches currently in stable-queue which might be from lee.jones@xxxxxxxxxx are queue-4.9/ion-protect-kref-from-userspace-manipulation.patch queue-4.9/ion-do-not-put-ion-handle-until-after-its-final-use.patch queue-4.9/ion-fix-use-after-free-during-ion_ioc_alloc.patch