drm/amdgpu: integer overflow in amdgpu_info_ioctl()

The "alloc_size" calculation can overflow leading to memory corruption.

Reviewed-by: Christian König <christian.koenig@amd.com>
Reported-by: Ilja Van Sprundel <ivansprundel@ioactive.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
index 22367939ebf1ad150cb3fe56a7470f0739d0dbcc..8c735f544b6608b0f814dfe2396650ddf9c8a34b 100644 (file)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_kms.c
@@ -390,7 +390,7 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
                                    min((size_t)size, sizeof(vram_gtt))) ? -EFAULT : 0;
        }
        case AMDGPU_INFO_READ_MMR_REG: {
-               unsigned n, alloc_size = info->read_mmr_reg.count * 4;
+               unsigned n, alloc_size;
                uint32_t *regs;
                unsigned se_num = (info->read_mmr_reg.instance >>
                                   AMDGPU_INFO_MMR_SE_INDEX_SHIFT) &
@@ -406,9 +406,10 @@ static int amdgpu_info_ioctl(struct drm_device *dev, void *data, struct drm_file
                if (sh_num == AMDGPU_INFO_MMR_SH_INDEX_MASK)
                        sh_num = 0xffffffff;
 
-               regs = kmalloc(alloc_size, GFP_KERNEL);
+               regs = kmalloc_array(info->read_mmr_reg.count, sizeof(*regs), GFP_KERNEL);
                if (!regs)
                        return -ENOMEM;
+               alloc_size = info->read_mmr_reg.count * sizeof(*regs);
 
                for (i = 0; i < info->read_mmr_reg.count; i++)
                        if (amdgpu_asic_read_register(adev, se_num, sh_num,