From: Greg Kroah-Hartman Date: Mon, 10 Sep 2018 08:30:42 +0000 (+0200) Subject: 4.4-stable patches X-Git-Tag: v4.4.156~40 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=7cbbef37c8a71f0b4c50957923bec51c8e4aa0fc;p=thirdparty%2Fkernel%2Fstable-queue.git 4.4-stable patches added patches: staging-android-ion-fix-ion_ioc_-map-share-use-after-free.patch --- diff --git a/queue-4.4/series b/queue-4.4/series index af19e7d6c2e..cbef77f8892 100644 --- a/queue-4.4/series +++ b/queue-4.4/series @@ -1 +1,2 @@ x86-speculation-l1tf-fix-up-pte-pfn-conversion-for-pae.patch +staging-android-ion-fix-ion_ioc_-map-share-use-after-free.patch diff --git a/queue-4.4/staging-android-ion-fix-ion_ioc_-map-share-use-after-free.patch b/queue-4.4/staging-android-ion-fix-ion_ioc_-map-share-use-after-free.patch new file mode 100644 index 00000000000..ebeea3aae01 --- /dev/null +++ b/queue-4.4/staging-android-ion-fix-ion_ioc_-map-share-use-after-free.patch @@ -0,0 +1,163 @@ +From stable-owner@vger.kernel.org Tue Sep 4 18:34:26 2018 +From: Greg Hackmann +Date: Tue, 4 Sep 2018 09:33:36 -0700 +Subject: staging: android: ion: fix ION_IOC_{MAP,SHARE} use-after-free +To: linux-kernel@vger.kernel.org +Cc: Laura Abbott , Sumit Semwal , Greg Kroah-Hartman , devel@driverdev.osuosl.org, kernel-team@android.com, Greg Hackmann , stable@vger.kernel.org +Message-ID: <20180904163336.234819-1-ghackmann@google.com> + +From: Greg Hackmann + +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 +--- +v2: remove Change-Id line from commit message + + drivers/staging/android/ion/ion.c | 60 +++++++++++++++++++++++--------------- + 1 file changed, 37 insertions(+), 23 deletions(-) + +--- a/drivers/staging/android/ion/ion.c ++++ b/drivers/staging/android/ion/ion.c +@@ -449,18 +449,6 @@ static struct ion_handle *ion_handle_get + return ERR_PTR(-EINVAL); + } + +-struct ion_handle *ion_handle_get_by_id(struct ion_client *client, +- int id) +-{ +- struct ion_handle *handle; +- +- mutex_lock(&client->lock); +- handle = ion_handle_get_by_id_nolock(client, id); +- mutex_unlock(&client->lock); +- +- return handle; +-} +- + static bool ion_handle_validate(struct ion_client *client, + struct ion_handle *handle) + { +@@ -1138,24 +1126,28 @@ static struct dma_buf_ops dma_buf_ops = + .kunmap = ion_dma_buf_kunmap, + }; + +-struct dma_buf *ion_share_dma_buf(struct ion_client *client, +- struct ion_handle *handle) ++static struct dma_buf *__ion_share_dma_buf(struct ion_client *client, ++ struct ion_handle *handle, ++ bool lock_client) + { + DEFINE_DMA_BUF_EXPORT_INFO(exp_info); + struct ion_buffer *buffer; + struct dma_buf *dmabuf; + bool valid_handle; + +- mutex_lock(&client->lock); ++ if (lock_client) ++ mutex_lock(&client->lock); + valid_handle = ion_handle_validate(client, handle); + if (!valid_handle) { + WARN(1, "%s: invalid handle passed to share.\n", __func__); +- mutex_unlock(&client->lock); ++ if (lock_client) ++ mutex_unlock(&client->lock); + return ERR_PTR(-EINVAL); + } + buffer = handle->buffer; + ion_buffer_get(buffer); +- mutex_unlock(&client->lock); ++ if (lock_client) ++ mutex_unlock(&client->lock); + + exp_info.ops = &dma_buf_ops; + exp_info.size = buffer->size; +@@ -1170,14 +1162,21 @@ struct dma_buf *ion_share_dma_buf(struct + + return dmabuf; + } ++ ++struct dma_buf *ion_share_dma_buf(struct ion_client *client, ++ struct ion_handle *handle) ++{ ++ return __ion_share_dma_buf(client, handle, true); ++} + EXPORT_SYMBOL(ion_share_dma_buf); + +-int ion_share_dma_buf_fd(struct ion_client *client, struct ion_handle *handle) ++static int __ion_share_dma_buf_fd(struct ion_client *client, ++ struct ion_handle *handle, bool lock_client) + { + struct dma_buf *dmabuf; + int fd; + +- dmabuf = ion_share_dma_buf(client, handle); ++ dmabuf = __ion_share_dma_buf(client, handle, lock_client); + if (IS_ERR(dmabuf)) + return PTR_ERR(dmabuf); + +@@ -1187,8 +1186,19 @@ int ion_share_dma_buf_fd(struct ion_clie + + return fd; + } ++ ++int ion_share_dma_buf_fd(struct ion_client *client, struct ion_handle *handle) ++{ ++ return __ion_share_dma_buf_fd(client, handle, true); ++} + EXPORT_SYMBOL(ion_share_dma_buf_fd); + ++static int ion_share_dma_buf_fd_nolock(struct ion_client *client, ++ struct ion_handle *handle) ++{ ++ return __ion_share_dma_buf_fd(client, handle, false); ++} ++ + struct ion_handle *ion_import_dma_buf(struct ion_client *client, int fd) + { + struct dma_buf *dmabuf; +@@ -1335,11 +1345,15 @@ static long ion_ioctl(struct file *filp, + { + struct ion_handle *handle; + +- handle = ion_handle_get_by_id(client, data.handle.handle); +- if (IS_ERR(handle)) ++ mutex_lock(&client->lock); ++ handle = ion_handle_get_by_id_nolock(client, data.handle.handle); ++ if (IS_ERR(handle)) { ++ mutex_unlock(&client->lock); + return PTR_ERR(handle); +- data.fd.fd = ion_share_dma_buf_fd(client, handle); +- ion_handle_put(handle); ++ } ++ data.fd.fd = ion_share_dma_buf_fd_nolock(client, handle); ++ ion_handle_put_nolock(handle); ++ mutex_unlock(&client->lock); + if (data.fd.fd < 0) + ret = data.fd.fd; + break;