From 0257b464b4d52a43cca6c8020b9586b2a6f46153 Mon Sep 17 00:00:00 2001 From: Jeremy Cline Date: Mon, 11 Jan 2021 16:05:28 -0500 Subject: [PATCH] drm/amdkfd: Fix out-of-bounds read in kdf_create_vcrat_image_cpu() KASAN reported a slab-out-of-bounds read of size 1 in kdf_create_vcrat_image_cpu(). This occurs when, for example, when on an x86_64 with a single NUMA node because kfd_fill_iolink_info_for_cpu() is a no-op, but afterwards the sub_type_hdr->length, which is out-of-bounds, is read and multiplied by entries. Fortunately, entries is 0 in this case so the overall crat_table->length is still correct. Check if there were any entries before de-referencing sub_type_hdr which may be pointing to out-of-bounds memory. Fixes: b7b6c38529c9 ("drm/amdkfd: Calculate CPU VCRAT size dynamically (v2)") Suggested-by: Felix Kuehling Signed-off-by: Jeremy Cline Reviewed-by: Felix Kuehling Signed-off-by: Felix Kuehling Signed-off-by: Alex Deucher --- drivers/gpu/drm/amd/amdkfd/kfd_crat.c | 11 +++++++---- 1 file changed, 7 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c index 8cac497..a5640a6 100644 --- a/drivers/gpu/drm/amd/amdkfd/kfd_crat.c +++ b/drivers/gpu/drm/amd/amdkfd/kfd_crat.c @@ -1040,11 +1040,14 @@ static int kfd_create_vcrat_image_cpu(void *pcrat_image, size_t *size) (struct crat_subtype_iolink *)sub_type_hdr); if (ret < 0) return ret; - crat_table->length += (sub_type_hdr->length * entries); - crat_table->total_entries += entries; - sub_type_hdr = (typeof(sub_type_hdr))((char *)sub_type_hdr + - sub_type_hdr->length * entries); + if (entries) { + crat_table->length += (sub_type_hdr->length * entries); + crat_table->total_entries += entries; + + sub_type_hdr = (typeof(sub_type_hdr))((char *)sub_type_hdr + + sub_type_hdr->length * entries); + } #else pr_info("IO link not available for non x86 platforms\n"); #endif -- 2.7.4