| Sažetak |
In the Linux kernel, the following vulnerability has been resolved:
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. |
