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 <[email protected]>
Cc: [email protected] (everything maintained past v2.6.37)
Cc: Samo Pogacnik <[email protected]>
---
 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;
                        case '\n':
-- 
1.7.10.4


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