Jiri Slaby 87d398f348 vt: keyboard, extend func_buf_lock to readers ... commit 82e61c3909 upstream. Both read-side users of func_table/func_buf need locking. Without that, one can easily confuse the code by repeatedly setting altering strings like: while (1) for (a = 0; a < 2; a++) { struct kbsentry kbs = {}; strcpy((char *)kbs.kb_string, a ? ".\n" : "88888\n"); ioctl(fd, KDSKBSENT, &kbs); } When that program runs, one can get unexpected output by holding F1 (note the unxpected period on the last line): . 88888 .8888 So protect all accesses to 'func_table' (and func_buf) by preexisting 'func_buf_lock'. It is easy in 'k_fn' handler as 'puts_queue' is expected not to sleep. On the other hand, KDGKBSENT needs a local (atomic) copy of the string because copy_to_user can sleep. Use already allocated, but unused 'kbs->kb_string' for that purpose. Note that the program above needs at least CAP_SYS_TTY_CONFIG. This depends on the previous patch and on the func_buf_lock lock added in commit 46ca3f735f (tty/vt: fix write/write race in ioctl(KDSKBSENT) handler) in 5.2. Likely fixes CVE-2020-25656. Cc: <stable@vger.kernel.org> Reported-by: Minh Yuan <yuanmingbuaa@gmail.com> Signed-off-by: Jiri Slaby <jslaby@suse.cz> Link: https://lore.kernel.org/r/20201019085517.10176-2-jslaby@suse.cz Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2020-11-05 11:43:29 +01:00
..
hvc	tty: hvcs: Don't NULL tty->driver_data until hvcs_cleanup()	2020-10-29 09:57:38 +01:00
ipwireless	tty: ipwireless: fix error handling	2020-10-29 09:58:08 +01:00
serdev	serdev: ttyport: restore client ops on deregistration	2020-02-28 17:22:19 +01:00
serial	serial: pl011: Fix lockdep splat when handling magic-sysrq interrupt	2020-11-01 12:01:06 +01:00
vt	vt: keyboard, extend func_buf_lock to readers	2020-11-05 11:43:29 +01:00
Kconfig	…
Makefile	…
amiserial.c	…
cyclades.c	…
ehv_bytechan.c	tty: evh_bytechan: Fix out of bounds accesses	2020-04-23 10:36:44 +02:00
goldfish.c	…
isicom.c	…
mips_ejtag_fdc.c	…
moxa.c	…
moxa.h	…
mxser.c	…
mxser.h	…
n_gsm.c	tty: n_gsm: Fix bogus i++ in gsm_data_kick	2020-06-24 17:50:29 +02:00
n_hdlc.c	tty: n_hdlc: fix build on SPARC	2019-10-04 15:14:20 +02:00
n_null.c	…
n_r3964.c	…
n_tracerouter.c	…
n_tracesink.c	…
n_tracesink.h	…
n_tty.c	…
nozomi.c	…
pty.c	pty: do tty_flip_buffer_push without port->lock in pty_write	2020-10-29 09:57:38 +01:00
rocket.c	tty: rocket, avoid OOB access	2020-04-29 16:33:17 +02:00
rocket.h	…
rocket_int.h	…
synclink.c	…
synclink_gt.c	tty: synclink_gt: Adjust indentation in several functions	2020-02-24 08:36:47 +01:00
synclinkmp.c	tty: synclinkmp: Adjust indentation in several functions	2020-02-24 08:36:47 +01:00
sysrq.c	…
tty_audit.c	…
tty_baudrate.c	…
tty_buffer.c	…
tty_io.c	tty: fix compat TIOCGSERIAL checking wrong function ptr	2020-03-25 08:25:52 +01:00
tty_ioctl.c	…
tty_jobctrl.c	…
tty_ldisc.c	…
tty_ldsem.c	…
tty_mutex.c	…
tty_port.c	serdev: ttyport: restore client ops on deregistration	2020-02-28 17:22:19 +01:00
ttynull.c	…
vcc.c	sparc64: vcc: Fix error return code in vcc_probe()	2020-10-01 13:17:57 +02:00