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Commit 336163dd authored by Yash Upadhyay's avatar Yash Upadhyay
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msm: camera: memmgr: Avoid TOCTOU buffer access on multiple use of same fd 



Fd is a user-accessible value, referring it multiple times
leads to TOCTOU issues. Dma_buf can be freed after the 1st
use of fd and userspace can create another dma_buf but with
same fd. In such scenario, during 2nd use of fd, we may get
a different dma_buf with different length. To avoid this, we
can use same dma_buf instead of retrieving it twice using same
fd. In this change FD is accessed only once in syscall.

CRs-Fixed: 3159446
Change-Id: I00eb6dd3d798165f5c6c0bd59feabe80a68592b1
Signed-off-by: default avatarYash Upadhyay <quic_yupadhya@quicinc.com>
parent d35e7e89

drivers/cam_req_mgr/cam_mem_mgr.c

+8 −7
Original line number Diff line number Diff line
@@ -577,7 +577,7 @@ static int cam_mem_util_check_map_flags(struct cam_mem_mgr_map_cmd *cmd) 
static int cam_mem_util_map_hw_va(uint32_t flags,

	int32_t *mmu_hdls,

	int32_t num_hdls,

	int fd,

	int fd, struct dma_buf *dmabuf,

	dma_addr_t *hw_vaddr,

	size_t *len,

	enum cam_smmu_region_id region,
@@ -606,7 +606,8 @@ static int cam_mem_util_map_hw_va(uint32_t flags, 
				fd,

				dir,

				hw_vaddr,

				len);

				len,

				dmabuf);



			if (rc < 0) {

				CAM_ERR(CAM_MEM,
@@ -624,7 +625,8 @@ static int cam_mem_util_map_hw_va(uint32_t flags, 
				(dma_addr_t *)hw_vaddr,

				len,

				region,

				is_internal);

				is_internal,

				dmabuf);



			if (rc < 0) {

				CAM_ERR(CAM_MEM,
@@ -716,6 +718,7 @@ int cam_mem_mgr_alloc_and_map(struct cam_mem_mgr_alloc_cmd *cmd) 
			cmd->mmu_hdls,

			cmd->num_hdl,

			fd,

			dmabuf,

			&hw_vaddr,

			&len,

			region,
@@ -856,6 +859,7 @@ int cam_mem_mgr_map(struct cam_mem_mgr_map_cmd *cmd) 
			cmd->mmu_hdls,

			cmd->num_hdl,

			cmd->fd,

			dmabuf,

			&hw_vaddr,

			&len,

			CAM_SMMU_REGION_IO,
@@ -1109,8 +1113,6 @@ static int cam_mem_util_unmap(int32_t idx, 
		if (cam_mem_util_unmap_hw_va(idx, region, client))

			CAM_ERR(CAM_MEM, "Failed, dmabuf=%pK",

				tbl.bufq[idx].dma_buf);

		if (client == CAM_SMMU_MAPPING_KERNEL)

			tbl.bufq[idx].dma_buf = NULL;

	}



	mutex_lock(&tbl.m_lock);
@@ -1126,7 +1128,6 @@ static int cam_mem_util_unmap(int32_t idx, 
		tbl.bufq[idx].is_imported,

		tbl.bufq[idx].dma_buf);



	if (tbl.bufq[idx].dma_buf)

	dma_buf_put(tbl.bufq[idx].dma_buf);



	tbl.bufq[idx].fd = -1;

drivers/cam_smmu/cam_smmu_api.c

+10 −29
Original line number Diff line number Diff line
@@ -262,7 +262,7 @@ static struct cam_dma_buff_info *cam_smmu_find_mapping_by_virt_address(int idx, 
static int cam_smmu_map_buffer_and_add_to_list(int idx, int ion_fd,

	bool dis_delayed_unmap, enum dma_data_direction dma_dir,

	dma_addr_t *paddr_ptr, size_t *len_ptr,

	enum cam_smmu_region_id region_id, bool is_internal);

	enum cam_smmu_region_id region_id, bool is_internal, struct dma_buf *dmabuf);



static int cam_smmu_map_kernel_buffer_and_add_to_list(int idx,

	struct dma_buf *buf, enum dma_data_direction dma_dir,
@@ -2028,7 +2028,7 @@ static int cam_smmu_map_buffer_validate(struct dma_buf *buf, 
	if (IS_ERR_OR_NULL(attach)) {

		rc = PTR_ERR(attach);

		CAM_ERR(CAM_SMMU, "Error: dma buf attach failed");

		goto err_put;

		goto err_out;

	}



	if (region_id == CAM_SMMU_REGION_SHARED) {
@@ -2175,8 +2175,6 @@ static int cam_smmu_map_buffer_validate(struct dma_buf *buf, 
	dma_buf_unmap_attachment(attach, table, dma_dir);

err_detach:

	dma_buf_detach(buf, attach);

err_put:

	dma_buf_put(buf);

err_out:

	return rc;

}
@@ -2185,14 +2183,10 @@ static int cam_smmu_map_buffer_validate(struct dma_buf *buf, 
static int cam_smmu_map_buffer_and_add_to_list(int idx, int ion_fd,

	bool dis_delayed_unmap, enum dma_data_direction dma_dir,

	dma_addr_t *paddr_ptr, size_t *len_ptr,

	enum cam_smmu_region_id region_id, bool is_internal)

	enum cam_smmu_region_id region_id, bool is_internal, struct dma_buf *buf)

{

	int rc = -1;

	struct cam_dma_buff_info *mapping_info = NULL;

	struct dma_buf *buf = NULL;



	/* returns the dma_buf structure related to an fd */

	buf = dma_buf_get(ion_fd);



	rc = cam_smmu_map_buffer_validate(buf, idx, dma_dir, paddr_ptr, len_ptr,

		region_id, dis_delayed_unmap, &mapping_info);
@@ -2316,7 +2310,6 @@ static int cam_smmu_unmap_buf_and_remove_from_list( 




	dma_buf_detach(mapping_info->buf, mapping_info->attach);

	dma_buf_put(mapping_info->buf);



	if (iommu_cb_set.map_profile_enable) {

		CAM_GET_TIMESTAMP(ts2);
@@ -2817,10 +2810,9 @@ int cam_smmu_put_scratch_iova(int handle, 


static int cam_smmu_map_stage2_buffer_and_add_to_list(int idx, int ion_fd,

		 enum dma_data_direction dma_dir, dma_addr_t *paddr_ptr,

		 size_t *len_ptr)

		 size_t *len_ptr, struct dma_buf *dmabuf)

{

	int rc = 0;

	struct dma_buf *dmabuf = NULL;

	struct dma_buf_attachment *attach = NULL;

	struct sg_table *table = NULL;

	struct cam_sec_buff_info *mapping_info;
@@ -2829,15 +2821,6 @@ static int cam_smmu_map_stage2_buffer_and_add_to_list(int idx, int ion_fd, 
	*paddr_ptr = (dma_addr_t)NULL;

	*len_ptr = (size_t)0;



	dmabuf = dma_buf_get(ion_fd);

	if (IS_ERR_OR_NULL((void *)(dmabuf))) {

		CAM_ERR(CAM_SMMU,

			"Error: dma buf get failed, idx=%d, ion_fd=%d",

			idx, ion_fd);

		rc = PTR_ERR(dmabuf);

		goto err_out;

	}



	/*

	 * ion_phys() is deprecated. call dma_buf_attach() and

	 * dma_buf_map_attachment() to get the buffer's physical
@@ -2849,7 +2832,7 @@ static int cam_smmu_map_stage2_buffer_and_add_to_list(int idx, int ion_fd, 
			"Error: dma buf attach failed, idx=%d, ion_fd=%d",

			idx, ion_fd);

		rc = PTR_ERR(attach);

		goto err_put;

		goto err_out;

	}



	attach->dma_map_attrs |= DMA_ATTR_SKIP_CPU_SYNC;
@@ -2895,15 +2878,14 @@ static int cam_smmu_map_stage2_buffer_and_add_to_list(int idx, int ion_fd, 
	dma_buf_unmap_attachment(attach, table, dma_dir);

err_detach:

	dma_buf_detach(dmabuf, attach);

err_put:

	dma_buf_put(dmabuf);

err_out:

	return rc;

}



int cam_smmu_map_stage2_iova(int handle,

		int ion_fd, enum cam_smmu_map_dir dir,

		dma_addr_t *paddr_ptr, size_t *len_ptr)

		dma_addr_t *paddr_ptr, size_t *len_ptr,

		struct dma_buf *dmabuf)

{

	int idx, rc;

	enum dma_data_direction dma_dir;
@@ -2962,7 +2944,7 @@ int cam_smmu_map_stage2_iova(int handle, 
		goto get_addr_end;

	}

	rc = cam_smmu_map_stage2_buffer_and_add_to_list(idx, ion_fd, dma_dir,

			paddr_ptr, len_ptr);

			paddr_ptr, len_ptr, dmabuf);

	if (rc < 0) {

		CAM_ERR(CAM_SMMU,

			"Error: mapping or add list fail, idx=%d, handle=%d, fd=%d, rc=%d",
@@ -2998,7 +2980,6 @@ static int cam_smmu_secure_unmap_buf_and_remove_from_list( 
	dma_buf_unmap_attachment(mapping_info->attach,

		mapping_info->table, mapping_info->dir);

	dma_buf_detach(mapping_info->buf, mapping_info->attach);

	dma_buf_put(mapping_info->buf);

	mapping_info->buf = NULL;



	list_del_init(&mapping_info->list);
@@ -3116,7 +3097,7 @@ static int cam_smmu_map_iova_validate_params(int handle, 
int cam_smmu_map_user_iova(int handle, int ion_fd, bool dis_delayed_unmap,

	enum cam_smmu_map_dir dir, dma_addr_t *paddr_ptr,

	size_t *len_ptr, enum cam_smmu_region_id region_id,

	bool is_internal)

	bool is_internal, struct dma_buf *dmabuf)

{

	int idx, rc = 0;

	struct timespec64 *ts = NULL;
@@ -3180,7 +3161,7 @@ int cam_smmu_map_user_iova(int handle, int ion_fd, bool dis_delayed_unmap, 


	rc = cam_smmu_map_buffer_and_add_to_list(idx, ion_fd,

		dis_delayed_unmap, dma_dir, paddr_ptr, len_ptr,

		region_id, is_internal);

		region_id, is_internal, dmabuf);

	if (rc < 0) {

		CAM_ERR(CAM_SMMU,

			"mapping or add list fail cb:%s idx=%d, fd=%d, region=%d, rc=%d",

drivers/cam_smmu/cam_smmu_api.h

+2 −2
Original line number Diff line number Diff line
@@ -128,7 +128,7 @@ int cam_smmu_ops(int handle, enum cam_smmu_ops_param op); 
 */

int cam_smmu_map_user_iova(int handle, int ion_fd, bool dis_delayed_unmap,

	enum cam_smmu_map_dir dir, dma_addr_t *dma_addr, size_t *len_ptr,

	enum cam_smmu_region_id region_id, bool is_internal);

	enum cam_smmu_region_id region_id, bool is_internal, struct dma_buf *dmabuf);



/**

 * @brief        : Maps kernel space IOVA for calling driver
@@ -304,7 +304,7 @@ int cam_smmu_put_iova(int handle, int ion_fd); 
 */

int cam_smmu_map_stage2_iova(int handle,

	int ion_fd, enum cam_smmu_map_dir dir, dma_addr_t *dma_addr,

	size_t *len_ptr);

	size_t *len_ptr, struct dma_buf *dmabuf);



/**

 * @brief Unmaps secure memopry for SMMU handle