ASoC: SOF: Intel: initialise and verify FW crash dump data.

FW mailbox offset was not set before use and HDR size was not validated.
Fix this.
Signed-off-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Link: https://lore.kernel.org/r/20190927200538.660-12-pierre-louis.bossart@linux.intel.comSigned-off-by: Mark Brown <broonie@kernel.org>

sound/soc/sof/intel/bdw.c

@@ -37,6 +37,7 @@
 #define MBOX_SIZE       0x1000
 #define MBOX_DUMP_SIZE 0x30
 #define EXCEPT_OFFSET	0x800
+#define EXCEPT_MAX_HDR_SIZE	0x400
 
 /* DSP peripherals */
 #define DMAC0_OFFSET    0xFE000
@@ -228,6 +229,11 @@ static void bdw_get_registers(struct snd_sof_dev *sdev,
 	/* note: variable AR register array is not read */
 
 	/* then get panic info */
+	if (xoops->arch_hdr.totalsize > EXCEPT_MAX_HDR_SIZE) {
+		dev_err(sdev->dev, "invalid header size 0x%x. FW oops is bogus\n",
+			xoops->arch_hdr.totalsize);
+		return;
+	}
 	offset += xoops->arch_hdr.totalsize;
 	sof_mailbox_read(sdev, offset, panic_info, sizeof(*panic_info));
 
@@ -451,6 +457,7 @@ static int bdw_probe(struct snd_sof_dev *sdev)
 	/* TODO: add offsets */
 	sdev->mmio_bar = BDW_DSP_BAR;
 	sdev->mailbox_bar = BDW_DSP_BAR;
+	sdev->dsp_oops_offset = MBOX_OFFSET;
 
 	/* PCI base */
 	mmio = platform_get_resource(pdev, IORESOURCE_MEM,

sound/soc/sof/intel/byt.c

@@ -28,6 +28,7 @@
 #define MBOX_OFFSET		0x144000
 #define MBOX_SIZE		0x1000
 #define EXCEPT_OFFSET		0x800
+#define EXCEPT_MAX_HDR_SIZE	0x400
 
 /* DSP peripherals */
 #define DMAC0_OFFSET		0x098000
@@ -126,6 +127,11 @@ static void byt_get_registers(struct snd_sof_dev *sdev,
 	/* note: variable AR register array is not read */
 
 	/* then get panic info */
+	if (xoops->arch_hdr.totalsize > EXCEPT_MAX_HDR_SIZE) {
+		dev_err(sdev->dev, "invalid header size 0x%x. FW oops is bogus\n",
+			xoops->arch_hdr.totalsize);
+		return;
+	}
 	offset += xoops->arch_hdr.totalsize;
 	sof_mailbox_read(sdev, offset, panic_info, sizeof(*panic_info));
 

sound/soc/sof/intel/hda.c

@@ -35,6 +35,8 @@
 #define IS_CFL(pci) ((pci)->vendor == 0x8086 && (pci)->device == 0xa348)
 #define IS_CNL(pci) ((pci)->vendor == 0x8086 && (pci)->device == 0x9dc8)
 
+#define EXCEPT_MAX_HDR_SIZE	0x400
+
 /*
  * Debug
  */
@@ -131,6 +133,11 @@ static void hda_dsp_get_registers(struct snd_sof_dev *sdev,
 	/* note: variable AR register array is not read */
 
 	/* then get panic info */
+	if (xoops->arch_hdr.totalsize > EXCEPT_MAX_HDR_SIZE) {
+		dev_err(sdev->dev, "invalid header size 0x%x. FW oops is bogus\n",
+			xoops->arch_hdr.totalsize);
+		return;
+	}
 	offset += xoops->arch_hdr.totalsize;
 	sof_block_read(sdev, sdev->mmio_bar, offset,
 		       panic_info, sizeof(*panic_info));