misc: issei: check bus message length before reading the command

Browse source

__issei_ham_process_ham_rsp() dispatches on hdr->cmd before the message
length is validated. The length comes from the firmware-owned DMA header
read in issei_dma_read(), which only bounds it from above, so firmware
sending a short bus message reaches the dispatch with less than
sizeof(struct ham_bus_message) bytes available.

For a zero-length message kmemdup() returns ZERO_SIZE_PTR, which passes
the NULL check in issei_dma_read(), and the dispatch dereferences it. A
length of one to three bytes gives a slab out-of-bounds read instead.

Reject bus messages shorter than the header before touching it, the way
the individual response handlers already validate their own length.

Fixes: 7bd4b9991d ("issei: implement main thread and ham messages")
Signed-off-by: Linmao Li <lilinmao@kylinos.cn>
Link: https://patch.msgid.link/20260731025952.3505287-1-lilinmao@kylinos.cn
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Linmao Li 2026-07-31 10:59:52 +08:00 • committed by Greg Kroah-Hartman

parent 9bcb5dbf0d

commit 220190f97d

1 changed files with 6 additions and 0 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

6

drivers/misc/issei/ham.c

View file