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authorGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-20 12:46:58 +0300
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-01-21 19:41:02 +0300
commit27cfb3a53be46a54ec5e0bd04e51995b74c90343 (patch)
tree04163f2cb58466c7620882f449e0af71ff100bae /drivers/tty
parentbfd8d8fe98b8792f362cd210a7873969f8d2fc04 (diff)
downloadlinux-27cfb3a53be46a54ec5e0bd04e51995b74c90343.tar.xz
tty: Handle problem if line discipline does not have receive_buf
Some tty line disciplines do not have a receive buf callback, so properly check for that before calling it. If they do not have this callback, just eat the character quietly, as we can't fail this call. Reported-by: Jann Horn <jannh@google.com> Cc: stable <stable@vger.kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty')
-rw-r--r--drivers/tty/tty_io.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 23c6fd238422..21ffcce16927 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2189,7 +2189,8 @@ static int tiocsti(struct tty_struct *tty, char __user *p)
ld = tty_ldisc_ref_wait(tty);
if (!ld)
return -EIO;
- ld->ops->receive_buf(tty, &ch, &mbz, 1);
+ if (ld->ops->receive_buf)
+ ld->ops->receive_buf(tty, &ch, &mbz, 1);
tty_ldisc_deref(ld);
return 0;
}