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usb: typec: ucsi: ccg: reject firmware images without a ':' record header

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do_flash() locates the first .cyacd record with

	p = strnchr(fw->data, fw->size, ':');
	while (p < eof) {
		s = strnchr(p + 1, eof - p - 1, ':');
		...
	}

If the firmware image contains no ':' byte,  strnchr() returns NULL.
NULL compares less than the valid kernel pointer eof, so the loop body
runs and strnchr() is called with p + 1 == (void *)1 and a length of
roughly (unsigned long)eof, causing a wonderful crash.

The not_signed_fw fallthrough earlier in do_flash() and the chip-state
branches in ccg_fw_update_needed() allow an unsigned blob to reach this
loop, so a root user who can place a crafted file under /lib/firmware
and write the do_flash sysfs attribute can trigger the oops.

Bail out with -EINVAL when the initial strnchr() returns NULL.

Assisted-by: gkh_clanker_t1000
Cc: stable <stable@kernel.org>
Cc: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Link: https://patch.msgid.link/2026051405-posture-shrill-7884@gregkh
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Greg Kroah-Hartman 2026-05-14 19:10:06 +02:00
parent 6c5dbc104d
commit d7486952bf
1 changed files with 5 additions and 0 deletions
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5
drivers/usb/typec/ucsi/ucsi_ccg.c
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@ -1243,6 +1243,11 @@ static int do_flash(struct ucsi_ccg *uc, enum enum_flash_mode mode)
*****************************************************************/
p = strnchr(fw->data, fw->size, ':');
if (!p) {
dev_err(dev, "Bad FW format: no ':' record header found\n");
err = -EINVAL;
goto release_mem;
}
while (p < eof) {
s = strnchr(p + 1, eof - p - 1, ':');