drm/radeon/kms/atom: make sure tables are valid (v2)

Check that atom cmd and data tables are valid
before using them.

(v2)
- fix some whitespace errors noticed by Rafał Miłecki
- check a few more cases

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 20 insertions, 12 deletions

diff --git a/drivers/gpu/drm/radeon/atom.c b/drivers/gpu/drm/radeon/atom.c
index b7fe660985c..247f8ee7e94 100644
--- a/drivers/gpu/drm/radeon/atom.c
+++ b/drivers/gpu/drm/radeon/atom.c
@@ -1295,12 +1295,16 @@ void atom_destroy(struct atom_context *ctx)
         kfree(ctx);
 }
 
-void atom_parse_data_header(struct atom_context *ctx, int index,
+bool atom_parse_data_header(struct atom_context *ctx, int index,
                             uint16_t * size, uint8_t * frev, uint8_t * crev,
                             uint16_t * data_start)
 {
         int offset = index * 2 + 4;
         int idx = CU16(ctx->data_table + offset);
+        u16 *mdt = (u16 *)(ctx->bios + ctx->data_table + 4);
+
+        if (!mdt[index])
+                return false;
 
         if (size)
                 *size = CU16(idx);
@@ -1309,38 +1313,42 @@ void atom_parse_data_header(struct atom_context *ctx, int index,
         if (crev)
                 *crev = CU8(idx + 3);
         *data_start = idx;
-        return;
+        return true;
 }
 
-void atom_parse_cmd_header(struct atom_context *ctx, int index, uint8_t * frev,
+bool atom_parse_cmd_header(struct atom_context *ctx, int index, uint8_t * frev,
                            uint8_t * crev)
 {
         int offset = index * 2 + 4;
         int idx = CU16(ctx->cmd_table + offset);
+        u16 *mct = (u16 *)(ctx->bios + ctx->cmd_table + 4);
+
+        if (!mct[index])
+                return false;
 
         if (frev)
                 *frev = CU8(idx + 2);
         if (crev)
                 *crev = CU8(idx + 3);
-        return;
+        return true;
 }
 
 int atom_allocate_fb_scratch(struct atom_context *ctx)
 {
         int index = GetIndexIntoMasterTable(DATA, VRAM_UsageByFirmware);
         uint16_t data_offset;
-        int usage_bytes;
+        int usage_bytes = 0;
         struct _ATOM_VRAM_USAGE_BY_FIRMWARE *firmware_usage;
 
-        atom_parse_data_header(ctx, index, NULL, NULL, NULL, &data_offset);
+        if (atom_parse_data_header(ctx, index, NULL, NULL, NULL, &data_offset)) {
+                firmware_usage = (struct _ATOM_VRAM_USAGE_BY_FIRMWARE *)(ctx->bios + data_offset);
 
-        firmware_usage = (struct _ATOM_VRAM_USAGE_BY_FIRMWARE *)(ctx->bios + data_offset);
+                DRM_DEBUG("atom firmware requested %08x %dkb\n",
+                          firmware_usage->asFirmwareVramReserveInfo[0].ulStartAddrUsedByFirmware,
+                          firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb);
 
-        DRM_DEBUG("atom firmware requested %08x %dkb\n",
-                  firmware_usage->asFirmwareVramReserveInfo[0].ulStartAddrUsedByFirmware,
-                  firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb);
-
-        usage_bytes = firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb * 1024;
+                usage_bytes = firmware_usage->asFirmwareVramReserveInfo[0].usFirmwareUseInKb * 1024;
+        }
         if (usage_bytes == 0)
                 usage_bytes = 20 * 1024;
         /* allocate some scratch memory */