spi/spidev: check message size before copying
Message size needs to be checked before copying, or bad things could
happen.
Signed-off-by: Domen Puncer <domen.puncer@telargo.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 225d6b2..bcfef04 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -168,6 +168,12 @@
n--, k_tmp++, u_tmp++) {
k_tmp->len = u_tmp->len;
+ total += k_tmp->len;
+ if (total > bufsiz) {
+ status = -EMSGSIZE;
+ goto done;
+ }
+
if (u_tmp->rx_buf) {
k_tmp->rx_buf = buf;
if (!access_ok(VERIFY_WRITE, u_tmp->rx_buf, u_tmp->len))
@@ -179,12 +185,6 @@
u_tmp->len))
goto done;
}
-
- total += k_tmp->len;
- if (total > bufsiz) {
- status = -EMSGSIZE;
- goto done;
- }
buf += k_tmp->len;
k_tmp->cs_change = !!u_tmp->cs_change;