Re: [alsa-devel] [PATCH v3 09/14] ASoC: SOF: Add firmware loader support

On Tue, 11 Dec 2018 22:23:13 +0100, Pierre-Louis Bossart wrote:

+/* generic module parser for mmaped DSPs */ +int snd_sof_parse_module_memcpy(struct snd_sof_dev *sdev,

• 		struct snd_sof_mod_hdr *module)
  

+{

• struct snd_sof_blk_hdr *block;
• int count;
• u32 offset;
• dev_dbg(sdev->dev, "new module size 0x%x blocks 0x%x type 0x%x\n",

• module->size, module->num_blocks, module->type);
  

• block = (void *)module + sizeof(*module);
• for (count = 0; count < module->num_blocks; count++) {

Need a sanity check that it won't go beyond the actual firmware size. User may pass a malicious module data, e.g. with extra large num_blocks.

• if (block->size == 0) {
  

• 	dev_warn(sdev->dev,
  

• 		 "warning: block %d size zero\n", count);
  

• 	dev_warn(sdev->dev, " type 0x%x offset 0x%x\n",
  

• 		 block->type, block->offset);
  

• 	continue;
  

• }
  

• switch (block->type) {
  

• case SOF_BLK_IMAGE:
  

• case SOF_BLK_CACHE:
  

• case SOF_BLK_REGS:
  

• case SOF_BLK_SIG:
  

• case SOF_BLK_ROM:
  

• 	continue;	/* not handled atm */
  

• case SOF_BLK_TEXT:
  

• case SOF_BLK_DATA:
  

• 	offset = block->offset;
  

• 	break;
  

• default:
  

• 	dev_err(sdev->dev, "error: bad type 0x%x for block 0x%x\n",
  

• 		block->type, count);
  

• 	return -EINVAL;
  

• }
  

• dev_dbg(sdev->dev,
  

• 	"block %d type 0x%x size 0x%x ==>  offset 0x%x\n",
  

• 	count, block->type, block->size, offset);
  

• snd_sof_dsp_block_write(sdev, offset,
  

• 			(void *)block + sizeof(*block),
  

• 			block->size);
  

• /* next block */
  

• block = (void *)block + sizeof(*block) + block->size;
  

This may lead to an unaligned access. Also how is the endianess guaranteed?

thanks,

Takashi