Re: [PATCH] iio: proximity: aw96103: validate firmware data length

[Jonathan Cameron <jic23@kernel.org>]

On Sun, 2 Aug 2026 19:21:34 +0100
Jonathan Cameron <jic23@kernel.org> wrote:

> On Sun,  2 Aug 2026 01:22:00 +0545
> Laxman Acharya Padhya <acharyalaxman8848@gmail.com> wrote:
> 
> > The firmware parser reads a length from the binary header and then uses
> > it to walk six-byte register/value entries. A truncated firmware image
> > can make the parser read beyond the copied firmware buffer. A value
> > smaller than the four-byte count field also underflows, producing a very
> > large length.
> > 
> > Read the little-endian field with get_unaligned_le32(), as previously
> > proposed by David Lechner. Validate the header size, reject an
> > underflowed length, ensure the resulting payload is contained in the
> > firmware image, and require it to contain whole register/value entries.
> > 
> > Fixes: 07b241262dca ("iio: proximity: aw96103: Add support for aw96103/aw96105 proximity sensor")
> > Link: https://lore.kernel.org/r/20260314-iio-proximity-aw96103-fix-firmware-read-v1-1-c74fe9ccd82b@baylibre.com
> > Cc: stable@vger.kernel.org
> > Signed-off-by: Laxman Acharya Padhya <acharyalaxman8848@gmail.com>  
> Looks fine to me, but I'll leave it on list a little while so others
> have time to take a look, ideally including Shuaijie Wang

Long enough - applied to the fixes-togreg branch of iio.git.

Note, I'll be rebasing on rc1 before sending this out so there is
still time for additional feedback.

Thanks,

Jonathan

> 
> Thanks
> 
> Jonathan
> 
> > ---
> >  drivers/iio/proximity/aw96103.c | 30 ++++++++++++++++++++++++------
> >  1 file changed, 24 insertions(+), 6 deletions(-)
> > 
> > diff --git a/drivers/iio/proximity/aw96103.c b/drivers/iio/proximity/aw96103.c
> > index 8fbb755dc..8352d51e5 100644
> > --- a/drivers/iio/proximity/aw96103.c
> > +++ b/drivers/iio/proximity/aw96103.c
> > @@ -24,6 +24,7 @@
> >  #define AW96103_BIN_VALID_DATA_OFFSET		64
> >  #define AW96103_BIN_DATA_LEN_OFFSET		16
> >  #define AW96103_BIN_DATA_REG_NUM_SIZE		4
> > +#define AW96103_BIN_REG_SIZE			6
> >  #define AW96103_BIN_CHIP_TYPE_SIZE		8
> >  #define AW96103_BIN_CHIP_TYPE_OFFSET		24
> >  
> > @@ -229,14 +230,27 @@ static const struct aw_chip_info aw_chip_info_tbl[] = {
> >  	},
> >  };
> >  
> > -static void aw96103_parsing_bin_file(struct aw_bin *bin)
> > +static int aw96103_parsing_bin_file(struct aw_bin *bin)
> >  {
> > +	u32 data_len;
> > +
> > +	if (bin->len < AW96103_BIN_VALID_DATA_OFFSET)
> > +		return -EINVAL;
> > +
> > +	data_len = get_unaligned_le32(bin->data + AW96103_BIN_DATA_LEN_OFFSET);
> > +	if (data_len < AW96103_BIN_DATA_REG_NUM_SIZE)
> > +		return -EINVAL;
> > +
> > +	bin->valid_data_len = data_len - AW96103_BIN_DATA_REG_NUM_SIZE;
> > +	if (bin->valid_data_len > bin->len - AW96103_BIN_VALID_DATA_OFFSET ||
> > +	    bin->valid_data_len % AW96103_BIN_REG_SIZE)
> > +		return -EINVAL;
> > +
> >  	bin->valid_data_addr = AW96103_BIN_VALID_DATA_OFFSET;
> > -	bin->valid_data_len =
> > -		*(unsigned int *)(bin->data + AW96103_BIN_DATA_LEN_OFFSET) -
> > -		AW96103_BIN_DATA_REG_NUM_SIZE;
> >  	memcpy(bin->chip_type, bin->data + AW96103_BIN_CHIP_TYPE_OFFSET,
> >  	       AW96103_BIN_CHIP_TYPE_SIZE);
> > +
> > +	return 0;
> >  }
> >  
> >  static const struct regmap_config aw96103_regmap_confg = {
> > @@ -500,7 +514,7 @@ static int aw96103_bin_valid_loaded(struct aw96103 *aw96103,
> >  	int ret;
> >  
> >  	for (i = 0; i < aw_bin_data_s->valid_data_len;
> > -	     i += 6, start_addr += 6) {
> > +	     i += AW96103_BIN_REG_SIZE, start_addr += AW96103_BIN_REG_SIZE) {
> >  		reg_addr = get_unaligned_le16(aw_bin_data_s->data + start_addr);
> >  		reg_data = get_unaligned_le32(aw_bin_data_s->data +
> >  					      start_addr + 2);
> > @@ -550,6 +564,8 @@ static int aw96103_para_loaded(struct aw96103 *aw96103)
> >  static int aw96103_cfg_all_loaded(const struct firmware *cont,
> >  				  struct aw96103 *aw96103)
> >  {
> > +	int ret;
> > +
> >  	if (!cont)
> >  		return -EINVAL;
> >  
> > @@ -561,7 +577,9 @@ static int aw96103_cfg_all_loaded(const struct firmware *cont,
> >  	aw_bin->len = cont->size;
> >  	memcpy(aw_bin->data, cont->data, cont->size);
> >  	release_firmware(cont);
> > -	aw96103_parsing_bin_file(aw_bin);
> > +	ret = aw96103_parsing_bin_file(aw_bin);
> > +	if (ret)
> > +		return ret;
> >  
> >  	return aw96103_bin_valid_loaded(aw96103, aw_bin);
> >  }  
> 
>