drm/amdgpu: Fix pointer casts when reading dynamic region sizes

The function amdgpu_virt_get_dynamic_data_info() writes a 64-bit size
value.  In two places (amdgpu_bios.c and amdgpu_discovery.c), the code
passed the address of a smaller variable by casting it to u64 *, which
is unsafe.

This could make the function write more bytes than the smaller variable
can hold, possibly overwriting nearby memory. Reported by static
analysis tools.

v2: Dynamic region size comes from the host (SR-IOV setup) and is always
fixed to 5 MB. (Lijo/Ellen)

5 MB easily fits inside a 32-bit value, so using a 64-bit type is not
needed. It also avoids extra type casts

Fixes: b4a8fcc7826a ("drm/amdgpu: Add logic for VF ipd and VF bios to init from dynamic crit_region offsets")
Reported by: Dan Carpenter <dan.carpenter@linaro.org>
Cc: Ellen Pan <yunru.pan@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Srinivasan Shanmugam <srinivasan.shanmugam@amd.com>
Reviewed-by: Lijo Lazar <lijo.lazar@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

4 files changed, 5 insertions, 5 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
index db705bf723f1..35d04e69aec0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_bios.c
@@ -103,7 +103,7 @@ static bool amdgpu_read_bios_from_vram(struct amdgpu_device *adev)
 {
 	uint8_t __iomem *bios = NULL;
 	resource_size_t vram_base;
-	resource_size_t size = 256 * 1024; /* ??? */
+	u32 size = 256U * 1024U; /* ??? */
 
 	if (!(adev->flags & AMD_IS_APU))
 		if (amdgpu_device_need_post(adev))
@@ -126,7 +126,7 @@ static bool amdgpu_read_bios_from_vram(struct amdgpu_device *adev)
 	 */
 	if (amdgpu_sriov_vf(adev) && adev->virt.is_dynamic_crit_regn_enabled) {
 		if (amdgpu_virt_get_dynamic_data_info(adev,
-				AMD_SRIOV_MSG_VBIOS_IMG_TABLE_ID, adev->bios, (uint64_t *)&size)) {
+				AMD_SRIOV_MSG_VBIOS_IMG_TABLE_ID, adev->bios, &size)) {
 			amdgpu_bios_release(adev);
 			return false;
 		}
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
index a7cb4665f485..fa2a22dfa048 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
@@ -311,7 +311,7 @@ static int amdgpu_discovery_read_binary_from_mem(struct amdgpu_device *adev,
 			 */
 			if (amdgpu_virt_get_dynamic_data_info(adev,
 						AMD_SRIOV_MSG_IPD_TABLE_ID, binary,
-						(uint64_t *)&adev->discovery.size)) {
+						&adev->discovery.size)) {
 				dev_err(adev->dev,
 						"failed to read discovery info from dynamic critical region.");
 				ret = -EINVAL;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
index 45f2ad083338..f2ce8f506aa8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
@@ -1102,7 +1102,7 @@ out:
 }
 
 int amdgpu_virt_get_dynamic_data_info(struct amdgpu_device *adev,
-	int data_id, uint8_t *binary, uint64_t *size)
+	int data_id, uint8_t *binary, u32 *size)
 {
 	uint32_t data_offset = 0;
 	uint32_t data_size = 0;
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
index 2a13cc892a13..14d864be5800 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.h
@@ -443,7 +443,7 @@ void amdgpu_virt_init(struct amdgpu_device *adev);
 
 int amdgpu_virt_init_critical_region(struct amdgpu_device *adev);
 int amdgpu_virt_get_dynamic_data_info(struct amdgpu_device *adev,
-	int data_id, uint8_t *binary, uint64_t *size);
+	int data_id, uint8_t *binary, u32 *size);
 
 bool amdgpu_virt_can_access_debugfs(struct amdgpu_device *adev);
 int amdgpu_virt_enable_access_debugfs(struct amdgpu_device *adev);