From d7486952bf74e546ee3748fb14b2d07881fa6273 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman Date: Thu, 14 May 2026 19:10:06 +0200 Subject: [PATCH] usb: typec: ucsi: ccg: reject firmware images without a ':' record header 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 Cc: Heikki Krogerus Reviewed-by: Heikki Krogerus Signed-off-by: Greg Kroah-Hartman Link: https://patch.msgid.link/2026051405-posture-shrill-7884@gregkh Signed-off-by: Greg Kroah-Hartman --- drivers/usb/typec/ucsi/ucsi_ccg.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/usb/typec/ucsi/ucsi_ccg.c b/drivers/usb/typec/ucsi/ucsi_ccg.c index 199799b319c2..4463c1ae96bd 100644 --- a/drivers/usb/typec/ucsi/ucsi_ccg.c +++ b/drivers/usb/typec/ucsi/ucsi_ccg.c @@ -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, ':');