[ 005/147] TTY: ttyprintk, dont touch behind tty->write_buf

Ben Hutchings
2012-10-14T15:16:47Z

From: Jiri Slaby <jslaby@suse.cz>

commit ee8b593affdf893012e57f4c54a21984d1b0d92e upstream.

If a user provides a buffer larger than a tty->write_buf chunk and
passes '\r' at the end of the buffer, we touch an out-of-bound memory.

Add a check there to prevent this.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Samo Pogacnik <samo_pogacnik@t-2.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
drivers/char/ttyprintk.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/char/ttyprintk.c b/drivers/char/ttyprintk.c
index 9b1e5e0..08755c5 100644
--- a/drivers/char/ttyprintk.c
+++ b/drivers/char/ttyprintk.c
@@ -67,7 +67,7 @@ static int tpk_printk(const unsigned char *buf, int count)
tmp[tpk_curr + 1] = '\0';
printk(KERN_INFO "%s%s", tpk_tag, tmp);
tpk_curr = 0;
- if (buf[i + 1] == '\n')
+ if ((i + 1) < count && buf[i + 1] == '\n')
i++;
break;