[v4,4/5] mtd: rawnand: brcmnand: Fix potential out-of-bounds access in oob write
Commit Message
When the oob buffer length is not in multiple of words, the oob write
function does out-of-bounds read on the oob source buffer at the last
iteration. Fix that by always checking length limit on the oob buffer
read and fill with 0xff when reaching the end of the buffer to the oob
registers.
Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller")
Signed-off-by: William Zhang <william.zhang@broadcom.com>
Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
Cc: stable@vger.kernel.org
---
Changes in v4:
- Add comments in the write_oob_to_regs function
- Add cc stable tag
Changes in v3:
- Fix kernel test robot sparse warning:
drivers/mtd/nand/raw/brcmnand/brcmnand.c:1500:54: sparse: expected unsigned int [usertype] data
drivers/mtd/nand/raw/brcmnand/brcmnand.c:1500:54: sparse: got restricted __be32 [usertype]
Changes in v2:
- Handle the remaining unaligned oob data after the oob data write loop
drivers/mtd/nand/raw/brcmnand/brcmnand.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
Comments
On Thu, 2023-07-06 at 18:29:08 UTC, William Zhang wrote:
> When the oob buffer length is not in multiple of words, the oob write
> function does out-of-bounds read on the oob source buffer at the last
> iteration. Fix that by always checking length limit on the oob buffer
> read and fill with 0xff when reaching the end of the buffer to the oob
> registers.
>
> Fixes: 27c5b17cd1b1 ("mtd: nand: add NAND driver "library" for Broadcom STB NAND controller")
> Signed-off-by: William Zhang <william.zhang@broadcom.com>
> Reviewed-by: Florian Fainelli <florian.fainelli@broadcom.com>
> Cc: stable@vger.kernel.org
Applied to https://git.kernel.org/pub/scm/linux/kernel/git/mtd/linux.git nand/next, thanks.
Miquel
@@ -1477,19 +1477,33 @@ static int write_oob_to_regs(struct brcmnand_controller *ctrl, int i,
const u8 *oob, int sas, int sector_1k)
{
int tbytes = sas << sector_1k;
- int j;
+ int j, k = 0;
+ u32 last = 0xffffffff;
+ u8 *plast = (u8 *)&last;
/* Adjust OOB values for 1K sector size */
if (sector_1k && (i & 0x01))
tbytes = max(0, tbytes - (int)ctrl->max_oob);
tbytes = min_t(int, tbytes, ctrl->max_oob);
- for (j = 0; j < tbytes; j += 4)
+ /*
+ * tbytes may not be multiple of words. Make sure we don't read out of
+ * the boundary and stop at last word.
+ */
+ for (j = 0; (j + 3) < tbytes; j += 4)
oob_reg_write(ctrl, j,
(oob[j + 0] << 24) |
(oob[j + 1] << 16) |
(oob[j + 2] << 8) |
(oob[j + 3] << 0));
+
+ /* handle the remaing bytes */
+ while (j < tbytes)
+ plast[k++] = oob[j++];
+
+ if (tbytes & 0x3)
+ oob_reg_write(ctrl, (tbytes & ~0x3), (__force u32)cpu_to_be32(last));
+
return tbytes;
}