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authorPeter Hurley <peter@hurleysoftware.com>2013-11-19 14:46:27 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-11-25 17:56:49 +0100
commitd4855e1fc03c2bb32dd64badf51cec5a2a26ab2a (patch)
treed518a39edafd6f58befb8d9f048ae8294b97b0b0 /drivers
parentTTY: amiserial, add missing platform check (diff)
downloadlinux-d4855e1fc03c2bb32dd64badf51cec5a2a26ab2a.tar.xz
linux-d4855e1fc03c2bb32dd64badf51cec5a2a26ab2a.zip
tty: Reset hupped state on open
A common security idiom is to hangup the current tty (via vhangup()) after forking but before execing a root shell. This hangs up any existing opens which other processes may have and ensures subsequent opens have the necessary permissions to open the root shell tty/pty. Reset the TTY_HUPPED state after the driver has successfully returned the opened tty (perform the reset while the tty is locked to avoid racing with concurrent hangups). Reported-by: Heorhi Valakhanovich <valahanovich@tut.by> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Cc: stable <stable@vger.kernel.org> # 3.12 Tested-by: Heorhi Valakhanovich <valahanovich@tut.by> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/tty/tty_io.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 3a1a01af9a80..c74a00ad7add 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -2086,6 +2086,7 @@ retry_open:
filp->f_op = &tty_fops;
goto retry_open;
}
+ clear_bit(TTY_HUPPED, &tty->flags);
tty_unlock(tty);