soc: qcom: mdt_loader: Validate that p_filesz < p_memsz

The code validates that segments of p_memsz bytes of a segment will fit
in the provided memory region, but does not validate that p_filesz bytes
will, which means that an incorrectly crafted ELF header might write
beyond the provided memory region.

Fixes: 051fb70f ("remoteproc: qcom: Driver for the self-authenticating Hexagon v5")
Reviewed-by: NSibi Sankar <sibis@codeaurora.org>
Link: https://lore.kernel.org/r/20210107233119.717173-1-bjorn.andersson@linaro.orgSigned-off-by: NBjorn Andersson <bjorn.andersson@linaro.org>

drivers/soc/qcom/mdt_loader.c

@@ -230,6 +230,14 @@ static int __qcom_mdt_load(struct device *dev, const struct firmware *fw,
 			break;
 		}
 
+		if (phdr->p_filesz > phdr->p_memsz) {
+			dev_err(dev,
+				"refusing to load segment %d with p_filesz > p_memsz\n",
+				i);
+			ret = -EINVAL;
+			break;
+		}
+
 		ptr = mem_region + offset;
 
 		if (phdr->p_filesz && phdr->p_offset < fw->size) {