diff options
Diffstat (limited to 'meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2021-44733.patch')
| -rw-r--r-- | meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2021-44733.patch | 339 |
1 files changed, 339 insertions, 0 deletions
diff --git a/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2021-44733.patch b/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2021-44733.patch new file mode 100644 index 000000000..a4f8b4d26 --- /dev/null +++ b/meta-openbmc-mods/meta-common/recipes-kernel/linux/linux-aspeed/CVE-2021-44733.patch @@ -0,0 +1,339 @@ +From 492eb7afe858d60408b2da09adc78540c4d16543 Mon Sep 17 00:00:00 2001 +From: Jens Wiklander <jens.wiklander@linaro.org> +Date: Thu, 9 Dec 2021 15:59:37 +0100 +Subject: [PATCH] tee: handle lookup of shm with reference count 0 + +commit dfd0743f1d9ea76931510ed150334d571fbab49d upstream. + +Since the tee subsystem does not keep a strong reference to its idle +shared memory buffers, it races with other threads that try to destroy a +shared memory through a close of its dma-buf fd or by unmapping the +memory. + +In tee_shm_get_from_id() when a lookup in teedev->idr has been +successful, it is possible that the tee_shm is in the dma-buf teardown +path, but that path is blocked by the teedev mutex. Since we don't have +an API to tell if the tee_shm is in the dma-buf teardown path or not we +must find another way of detecting this condition. + +Fix this by doing the reference counting directly on the tee_shm using a +new refcount_t refcount field. dma-buf is replaced by using +anon_inode_getfd() instead, this separates the life-cycle of the +underlying file from the tee_shm. tee_shm_put() is updated to hold the +mutex when decreasing the refcount to 0 and then remove the tee_shm from +teedev->idr before releasing the mutex. This means that the tee_shm can +never be found unless it has a refcount larger than 0. + +Fixes: 967c9cca2cc5 ("tee: generic TEE subsystem") +Cc: stable@vger.kernel.org +Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +Reviewed-by: Lars Persson <larper@axis.com> +Reviewed-by: Sumit Garg <sumit.garg@linaro.org> +Reported-by: Patrik Lantz <patrik.lantz@axis.com> +Signed-off-by: Jens Wiklander <jens.wiklander@linaro.org> +Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> +--- + drivers/tee/tee_shm.c | 171 ++++++++++++++++------------------------ + include/linux/tee_drv.h | 4 +- + 2 files changed, 68 insertions(+), 107 deletions(-) + +diff --git a/drivers/tee/tee_shm.c b/drivers/tee/tee_shm.c +index 8a9384a64f3e29..499fccba3d74bd 100644 +--- a/drivers/tee/tee_shm.c ++++ b/drivers/tee/tee_shm.c +@@ -1,11 +1,11 @@ + // SPDX-License-Identifier: GPL-2.0-only + /* +- * Copyright (c) 2015-2016, Linaro Limited ++ * Copyright (c) 2015-2017, 2019-2021 Linaro Limited + */ ++#include <linux/anon_inodes.h> + #include <linux/device.h> +-#include <linux/dma-buf.h> +-#include <linux/fdtable.h> + #include <linux/idr.h> ++#include <linux/mm.h> + #include <linux/sched.h> + #include <linux/slab.h> + #include <linux/tee_drv.h> +@@ -28,16 +28,8 @@ static void release_registered_pages(struct tee_shm *shm) + } + } + +-static void tee_shm_release(struct tee_shm *shm) ++static void tee_shm_release(struct tee_device *teedev, struct tee_shm *shm) + { +- struct tee_device *teedev = shm->ctx->teedev; +- +- if (shm->flags & TEE_SHM_DMA_BUF) { +- mutex_lock(&teedev->mutex); +- idr_remove(&teedev->idr, shm->id); +- mutex_unlock(&teedev->mutex); +- } +- + if (shm->flags & TEE_SHM_POOL) { + struct tee_shm_pool_mgr *poolm; + +@@ -64,45 +56,6 @@ static void tee_shm_release(struct tee_shm *shm) + tee_device_put(teedev); + } + +-static struct sg_table *tee_shm_op_map_dma_buf(struct dma_buf_attachment +- *attach, enum dma_data_direction dir) +-{ +- return NULL; +-} +- +-static void tee_shm_op_unmap_dma_buf(struct dma_buf_attachment *attach, +- struct sg_table *table, +- enum dma_data_direction dir) +-{ +-} +- +-static void tee_shm_op_release(struct dma_buf *dmabuf) +-{ +- struct tee_shm *shm = dmabuf->priv; +- +- tee_shm_release(shm); +-} +- +-static int tee_shm_op_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) +-{ +- struct tee_shm *shm = dmabuf->priv; +- size_t size = vma->vm_end - vma->vm_start; +- +- /* Refuse sharing shared memory provided by application */ +- if (shm->flags & TEE_SHM_USER_MAPPED) +- return -EINVAL; +- +- return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT, +- size, vma->vm_page_prot); +-} +- +-static const struct dma_buf_ops tee_shm_dma_buf_ops = { +- .map_dma_buf = tee_shm_op_map_dma_buf, +- .unmap_dma_buf = tee_shm_op_unmap_dma_buf, +- .release = tee_shm_op_release, +- .mmap = tee_shm_op_mmap, +-}; +- + struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags) + { + struct tee_device *teedev = ctx->teedev; +@@ -137,6 +90,7 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags) + goto err_dev_put; + } + ++ refcount_set(&shm->refcount, 1); + shm->flags = flags | TEE_SHM_POOL; + shm->ctx = ctx; + if (flags & TEE_SHM_DMA_BUF) +@@ -150,10 +104,7 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags) + goto err_kfree; + } + +- + if (flags & TEE_SHM_DMA_BUF) { +- DEFINE_DMA_BUF_EXPORT_INFO(exp_info); +- + mutex_lock(&teedev->mutex); + shm->id = idr_alloc(&teedev->idr, shm, 1, 0, GFP_KERNEL); + mutex_unlock(&teedev->mutex); +@@ -161,28 +112,11 @@ struct tee_shm *tee_shm_alloc(struct tee_context *ctx, size_t size, u32 flags) + ret = ERR_PTR(shm->id); + goto err_pool_free; + } +- +- exp_info.ops = &tee_shm_dma_buf_ops; +- exp_info.size = shm->size; +- exp_info.flags = O_RDWR; +- exp_info.priv = shm; +- +- shm->dmabuf = dma_buf_export(&exp_info); +- if (IS_ERR(shm->dmabuf)) { +- ret = ERR_CAST(shm->dmabuf); +- goto err_rem; +- } + } + + teedev_ctx_get(ctx); + + return shm; +-err_rem: +- if (flags & TEE_SHM_DMA_BUF) { +- mutex_lock(&teedev->mutex); +- idr_remove(&teedev->idr, shm->id); +- mutex_unlock(&teedev->mutex); +- } + err_pool_free: + poolm->ops->free(poolm, shm); + err_kfree: +@@ -243,6 +177,7 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr, + goto err; + } + ++ refcount_set(&shm->refcount, 1); + shm->flags = flags | TEE_SHM_REGISTER; + shm->ctx = ctx; + shm->id = -1; +@@ -303,22 +238,6 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr, + goto err; + } + +- if (flags & TEE_SHM_DMA_BUF) { +- DEFINE_DMA_BUF_EXPORT_INFO(exp_info); +- +- exp_info.ops = &tee_shm_dma_buf_ops; +- exp_info.size = shm->size; +- exp_info.flags = O_RDWR; +- exp_info.priv = shm; +- +- shm->dmabuf = dma_buf_export(&exp_info); +- if (IS_ERR(shm->dmabuf)) { +- ret = ERR_CAST(shm->dmabuf); +- teedev->desc->ops->shm_unregister(ctx, shm); +- goto err; +- } +- } +- + return shm; + err: + if (shm) { +@@ -336,6 +255,35 @@ struct tee_shm *tee_shm_register(struct tee_context *ctx, unsigned long addr, + } + EXPORT_SYMBOL_GPL(tee_shm_register); + ++static int tee_shm_fop_release(struct inode *inode, struct file *filp) ++{ ++ tee_shm_put(filp->private_data); ++ return 0; ++} ++ ++static int tee_shm_fop_mmap(struct file *filp, struct vm_area_struct *vma) ++{ ++ struct tee_shm *shm = filp->private_data; ++ size_t size = vma->vm_end - vma->vm_start; ++ ++ /* Refuse sharing shared memory provided by application */ ++ if (shm->flags & TEE_SHM_USER_MAPPED) ++ return -EINVAL; ++ ++ /* check for overflowing the buffer's size */ ++ if (vma->vm_pgoff + vma_pages(vma) > shm->size >> PAGE_SHIFT) ++ return -EINVAL; ++ ++ return remap_pfn_range(vma, vma->vm_start, shm->paddr >> PAGE_SHIFT, ++ size, vma->vm_page_prot); ++} ++ ++static const struct file_operations tee_shm_fops = { ++ .owner = THIS_MODULE, ++ .release = tee_shm_fop_release, ++ .mmap = tee_shm_fop_mmap, ++}; ++ + /** + * tee_shm_get_fd() - Increase reference count and return file descriptor + * @shm: Shared memory handle +@@ -348,10 +296,11 @@ int tee_shm_get_fd(struct tee_shm *shm) + if (!(shm->flags & TEE_SHM_DMA_BUF)) + return -EINVAL; + +- get_dma_buf(shm->dmabuf); +- fd = dma_buf_fd(shm->dmabuf, O_CLOEXEC); ++ /* matched by tee_shm_put() in tee_shm_op_release() */ ++ refcount_inc(&shm->refcount); ++ fd = anon_inode_getfd("tee_shm", &tee_shm_fops, shm, O_RDWR); + if (fd < 0) +- dma_buf_put(shm->dmabuf); ++ tee_shm_put(shm); + return fd; + } + +@@ -361,17 +310,7 @@ int tee_shm_get_fd(struct tee_shm *shm) + */ + void tee_shm_free(struct tee_shm *shm) + { +- /* +- * dma_buf_put() decreases the dmabuf reference counter and will +- * call tee_shm_release() when the last reference is gone. +- * +- * In the case of driver private memory we call tee_shm_release +- * directly instead as it doesn't have a reference counter. +- */ +- if (shm->flags & TEE_SHM_DMA_BUF) +- dma_buf_put(shm->dmabuf); +- else +- tee_shm_release(shm); ++ tee_shm_put(shm); + } + EXPORT_SYMBOL_GPL(tee_shm_free); + +@@ -478,10 +417,15 @@ struct tee_shm *tee_shm_get_from_id(struct tee_context *ctx, int id) + teedev = ctx->teedev; + mutex_lock(&teedev->mutex); + shm = idr_find(&teedev->idr, id); ++ /* ++ * If the tee_shm was found in the IDR it must have a refcount ++ * larger than 0 due to the guarantee in tee_shm_put() below. So ++ * it's safe to use refcount_inc(). ++ */ + if (!shm || shm->ctx != ctx) + shm = ERR_PTR(-EINVAL); +- else if (shm->flags & TEE_SHM_DMA_BUF) +- get_dma_buf(shm->dmabuf); ++ else ++ refcount_inc(&shm->refcount); + mutex_unlock(&teedev->mutex); + return shm; + } +@@ -493,7 +437,24 @@ EXPORT_SYMBOL_GPL(tee_shm_get_from_id); + */ + void tee_shm_put(struct tee_shm *shm) + { +- if (shm->flags & TEE_SHM_DMA_BUF) +- dma_buf_put(shm->dmabuf); ++ struct tee_device *teedev = shm->ctx->teedev; ++ bool do_release = false; ++ ++ mutex_lock(&teedev->mutex); ++ if (refcount_dec_and_test(&shm->refcount)) { ++ /* ++ * refcount has reached 0, we must now remove it from the ++ * IDR before releasing the mutex. This will guarantee that ++ * the refcount_inc() in tee_shm_get_from_id() never starts ++ * from 0. ++ */ ++ if (shm->flags & TEE_SHM_DMA_BUF) ++ idr_remove(&teedev->idr, shm->id); ++ do_release = true; ++ } ++ mutex_unlock(&teedev->mutex); ++ ++ if (do_release) ++ tee_shm_release(teedev, shm); + } + EXPORT_SYMBOL_GPL(tee_shm_put); +diff --git a/include/linux/tee_drv.h b/include/linux/tee_drv.h +index 3ebfea0781f100..feda1dc7f98ee7 100644 +--- a/include/linux/tee_drv.h ++++ b/include/linux/tee_drv.h +@@ -195,7 +195,7 @@ int tee_session_calc_client_uuid(uuid_t *uuid, u32 connection_method, + * @offset: offset of buffer in user space + * @pages: locked pages from userspace + * @num_pages: number of locked pages +- * @dmabuf: dmabuf used to for exporting to user space ++ * @refcount: reference counter + * @flags: defined by TEE_SHM_* in tee_drv.h + * @id: unique id of a shared memory object on this device + * +@@ -210,7 +210,7 @@ struct tee_shm { + unsigned int offset; + struct page **pages; + size_t num_pages; +- struct dma_buf *dmabuf; ++ refcount_t refcount; + u32 flags; + int id; + }; + |