The receive byte count comes from device-controlled status registers, but the packet splitter unconditionally consumes a four-byte delimiter. A count of one to three bytes therefore makes bytes_remaining negative. If the reused receive buffer contains a valid delimiter, the negative value is passed to memcpy() and converted to a near-SIZE_MAX length, corrupting kernel memory. YAPS streams are word aligned, so reject byte counts that cannot contain complete delimiters. Also reject delimiter sizes which do not leave any packet data after removing the reserved metadata page. Fixes: b1906cea00b0 ("wifi: mm81x: add mm81x Wi-Fi HaLow driver") Assisted-by: Codex:gpt-5 Signed-off-by: Felix Hoffmann --- drivers/net/wireless/morsemicro/mm81x/yaps_hw.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/morsemicro/mm81x/yaps_hw.c b/drivers/net/wireless/morsemicro/mm81x/yaps_hw.c index 3d641d23c35b..97b2ff93c69f 100644 --- a/drivers/net/wireless/morsemicro/mm81x/yaps_hw.c +++ b/drivers/net/wireless/morsemicro/mm81x/yaps_hw.c @@ -407,7 +407,7 @@ static bool mm81x_read_pkts_h_is_valid_delim(u32 delim) if (calc_crc != YAPS_DELIM_GET_CRC(delim)) return false; - if (pkt_size == 0) + if (pkt_size <= YAPS_RESERVED_PAGE_SIZE) return false; if ((pkt_size + padding) > YAPS_MAX_PKT_SIZE_BYTES) @@ -455,6 +455,10 @@ static int mm81x_yaps_hw_read_pkts(struct mm81x_yaps *yaps, return 0; if (bytes_remaining < 0) return bytes_remaining; + if (!IS_ALIGNED(bytes_remaining, sizeof(u32))) { + dev_warn(yaps->mors->dev, "yaps truncated delimiter"); + return -EIO; + } if (bytes_remaining > YAPS_HW_WINDOW_SIZE_BYTES) { bytes_remaining = YAPS_HW_WINDOW_SIZE_BYTES; -- 2.43.0