firewire: cdev: require quadlet-aligned headers for transmit packets
The definition of struct fw_cdev_iso_packet seems to imply that the
header_length must be quadlet-aligned, and in fact, specifying an
unaligned header has never really worked when using multiple packet
structures, because the position of the next control word is computed by
rounding the header_length _down_, so the last one to three bytes of the
header would overlap the next control word.
To avoid this problem, check that the header length is properly aligned.
Signed-off-by: Clemens Ladisch <clemens@ladisch.de>
Signed-off-by: Stefan Richter <stefanr@s5r6.in-berlin.de>
diff --git a/drivers/firewire/core-cdev.c b/drivers/firewire/core-cdev.c
index bbb8160..5eba9e0 100644
--- a/drivers/firewire/core-cdev.c
+++ b/drivers/firewire/core-cdev.c
@@ -959,6 +959,8 @@
u.packet.header_length = GET_HEADER_LENGTH(control);
if (ctx->type == FW_ISO_CONTEXT_TRANSMIT) {
+ if (u.packet.header_length % 4 != 0)
+ return -EINVAL;
header_length = u.packet.header_length;
} else {
/*