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vt_in_use() dereferences console_driver->ttys[i] without proper locking.
This is broken because the tty can be closed and freed concurrently.
We could fix this by using 'READ_ONCE(console_driver->ttys[i]) != NULL'
and skipping the check of tty_struct::count. But, looking at
console_driver->ttys[i] isn't really appropriate anyway because even if
it is NULL the tty can still be in the process of being closed.
Instead, fix it by making vt_in_use() require console_lock() and check
whether the vt is allocated and has port refcount > 1. This works since
following the patch "vt: vt_ioctl: fix VT_DISALLOCATE freeing in-use
virtual console" the port refcount is incremented while the vt is open.
Reproducer (very unreliable, but it worked for me after a few minutes):
#include <fcntl.h>
#include <linux/vt.h>
int main()
{
int fd, nproc;
struct vt_stat state;
char ttyname[16];
fd = open("/dev/tty10", O_RDONLY);
for (nproc = 1; nproc < 8; nproc *= 2)
fork();
for (;;) {
sprintf(ttyname, "/dev/tty%d", rand() % 8);
close(open(ttyname, O_RDONLY));
ioctl(fd, VT_GETSTATE, &state);
}
}
KASAN report:
BUG: KASAN: use-after-free in vt_in_use drivers/tty/vt/vt_ioctl.c:48 [inline]
BUG: KASAN: use-after-free in vt_ioctl+0x1ad3/0x1d70 drivers/tty/vt/vt_ioctl.c:657
Read of size 4 at addr ffff888065722468 by task syz-vt2/132
CPU: 0 PID: 132 Comm: syz-vt2 Not tainted 5.6.0-rc5-00130-g089b6d3654916 #13
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20191223_100556-anatol 04/01/2014
Call Trace:
[...]
vt_in_use drivers/tty/vt/vt_ioctl.c:48 [inline]
vt_ioctl+0x1ad3/0x1d70 drivers/tty/vt/vt_ioctl.c:657
tty_ioctl+0x9db/0x11b0 drivers/tty/tty_io.c:2660
[...]
Allocated by task 136:
[...]
kzalloc include/linux/slab.h:669 [inline]
alloc_tty_struct+0x96/0x8a0 drivers/tty/tty_io.c:2982
tty_init_dev+0x23/0x350 drivers/tty/tty_io.c:1334
tty_open_by_driver drivers/tty/tty_io.c:1987 [inline]
tty_open+0x3ca/0xb30 drivers/tty/tty_io.c:2035
[...]
Freed by task 41:
[...]
kfree+0xbf/0x200 mm/slab.c:3757
free_tty_struct+0x8d/0xb0 drivers/tty/tty_io.c:177
release_one_tty+0x22d/0x2f0 drivers/tty/tty_io.c:1468
process_one_work+0x7f1/0x14b0 kernel/workqueue.c:2264
worker_thread+0x8b/0xc80 kernel/workqueue.c:2410
[...]
Fixes: 4001d7b7fc27 ("vt: push down the tty lock so we can see what is left to tackle")
Cc: <stable@vger.kernel.org> # v3.4+
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200322034305.210082-3-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The VT_DISALLOCATE ioctl can free a virtual console while tty_release()
is still running, causing a use-after-free in con_shutdown(). This
occurs because VT_DISALLOCATE considers a virtual console's
'struct vc_data' to be unused as soon as the corresponding tty's
refcount hits 0. But actually it may be still being closed.
Fix this by making vc_data be reference-counted via the embedded
'struct tty_port'. A newly allocated virtual console has refcount 1.
Opening it for the first time increments the refcount to 2. Closing it
for the last time decrements the refcount (in tty_operations::cleanup()
so that it happens late enough), as does VT_DISALLOCATE.
Reproducer:
#include <fcntl.h>
#include <linux/vt.h>
#include <sys/ioctl.h>
#include <unistd.h>
int main()
{
if (fork()) {
for (;;)
close(open("/dev/tty5", O_RDWR));
} else {
int fd = open("/dev/tty10", O_RDWR);
for (;;)
ioctl(fd, VT_DISALLOCATE, 5);
}
}
KASAN report:
BUG: KASAN: use-after-free in con_shutdown+0x76/0x80 drivers/tty/vt/vt.c:3278
Write of size 8 at addr ffff88806a4ec108 by task syz_vt/129
CPU: 0 PID: 129 Comm: syz_vt Not tainted 5.6.0-rc2 #11
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS ?-20191223_100556-anatol 04/01/2014
Call Trace:
[...]
con_shutdown+0x76/0x80 drivers/tty/vt/vt.c:3278
release_tty+0xa8/0x410 drivers/tty/tty_io.c:1514
tty_release_struct+0x34/0x50 drivers/tty/tty_io.c:1629
tty_release+0x984/0xed0 drivers/tty/tty_io.c:1789
[...]
Allocated by task 129:
[...]
kzalloc include/linux/slab.h:669 [inline]
vc_allocate drivers/tty/vt/vt.c:1085 [inline]
vc_allocate+0x1ac/0x680 drivers/tty/vt/vt.c:1066
con_install+0x4d/0x3f0 drivers/tty/vt/vt.c:3229
tty_driver_install_tty drivers/tty/tty_io.c:1228 [inline]
tty_init_dev+0x94/0x350 drivers/tty/tty_io.c:1341
tty_open_by_driver drivers/tty/tty_io.c:1987 [inline]
tty_open+0x3ca/0xb30 drivers/tty/tty_io.c:2035
[...]
Freed by task 130:
[...]
kfree+0xbf/0x1e0 mm/slab.c:3757
vt_disallocate drivers/tty/vt/vt_ioctl.c:300 [inline]
vt_ioctl+0x16dc/0x1e30 drivers/tty/vt/vt_ioctl.c:818
tty_ioctl+0x9db/0x11b0 drivers/tty/tty_io.c:2660
[...]
Fixes: 4001d7b7fc27 ("vt: push down the tty lock so we can see what is left to tackle")
Cc: <stable@vger.kernel.org> # v3.4+
Reported-by: syzbot+522643ab5729b0421998@syzkaller.appspotmail.com
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200322034305.210082-2-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Shift cases one level left. This makes the code more readable and some
lines need not wrap anymore.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200316065911.11024-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We have a helper called rounddown for these modulo computations. So use
it.
No functional change intended and "objdump -d" proves that.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200316065911.11024-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Instead of awkward ternary operator with comparison, use simple min()
for blankinterval and vesa_off_interval.
No functional change intended and "objdump -d" proves that.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200316065911.11024-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The merge commit cb05c6c82fb0 (Merge 5.6-rc5 into tty-next) introduced a
double lock to set_selection_kernel. vc_sel.lock is locked both in
set_selection_kernel and its callee __set_selection_kernel now.
Remove the latter.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Link: https://lore.kernel.org/r/20200316064544.4799-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The vc_cons_allocated() checks in vt_ioctl() and vt_compat_ioctl() are
unnecessary because they can only be reached by calling ioctl() on an
open tty, which implies the corresponding virtual console is allocated.
And even if the virtual console *could* be freed concurrently, then
these checks would be broken since they aren't done under console_lock,
and the vc_data is dereferenced before them anyway.
So, remove these unneeded checks to avoid confusion.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200224080326.295046-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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The might_sleep() in do_con_write() is redundant because console_lock()
already contains might_sleep(). Remove it.
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20200224073450.292892-1-ebiggers@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We need the vt fixes in here and it resolves a merge issue with
drivers/tty/vt/selection.c
Reported-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Shift the cases one level left as this is how we are supposed to write
the switch-case code according to the CodingStyle.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-9-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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It is declared in vt_kern.h, so no need to declare it in selection.c
which includes the header.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-8-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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vt_dont_switch is pure boolean, no need for whole char.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-6-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Move all the selection global variables to a structure vc_selection,
instantiated as vc_sel. This helps to group all the variables together
and see what should be protected by the embedded lock too.
It might be used later also for per-console selection support.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-5-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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use_unicode needs not be global. It is used only in set_selection_kernel
and sel_pos (a callee). It is also always set there prior calling
sel_pos. So make use_unicode local and rename it to plain shorter
"unicode". Finally, propagate it to sel_pos via parameter.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-4-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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multiplier and mode are not actually needed:
* multiplier is used only in kmalloc_array, so use "use_unicode ? 4 : 1"
directly
* mode is used only to assign a bool in this manner:
if (cond)
x = true;
else
x = false;
So do "x = cond" directly.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-3-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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sel_lock cannot nest in the console lock. Thanks to syzkaller, the
kernel states firmly:
> WARNING: possible circular locking dependency detected
> 5.6.0-rc3-syzkaller #0 Not tainted
> ------------------------------------------------------
> syz-executor.4/20336 is trying to acquire lock:
> ffff8880a2e952a0 (&tty->termios_rwsem){++++}, at: tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136
>
> but task is already holding lock:
> ffffffff89462e70 (sel_lock){+.+.}, at: paste_selection+0x118/0x470 drivers/tty/vt/selection.c:374
>
> which lock already depends on the new lock.
>
> the existing dependency chain (in reverse order) is:
>
> -> #2 (sel_lock){+.+.}:
> mutex_lock_nested+0x1b/0x30 kernel/locking/mutex.c:1118
> set_selection_kernel+0x3b8/0x18a0 drivers/tty/vt/selection.c:217
> set_selection_user+0x63/0x80 drivers/tty/vt/selection.c:181
> tioclinux+0x103/0x530 drivers/tty/vt/vt.c:3050
> vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364
This is ioctl(TIOCL_SETSEL).
Locks held on the path: console_lock -> sel_lock
> -> #1 (console_lock){+.+.}:
> console_lock+0x46/0x70 kernel/printk/printk.c:2289
> con_flush_chars+0x50/0x650 drivers/tty/vt/vt.c:3223
> n_tty_write+0xeae/0x1200 drivers/tty/n_tty.c:2350
> do_tty_write drivers/tty/tty_io.c:962 [inline]
> tty_write+0x5a1/0x950 drivers/tty/tty_io.c:1046
This is write().
Locks held on the path: termios_rwsem -> console_lock
> -> #0 (&tty->termios_rwsem){++++}:
> down_write+0x57/0x140 kernel/locking/rwsem.c:1534
> tty_unthrottle+0x22/0x100 drivers/tty/tty_ioctl.c:136
> mkiss_receive_buf+0x12aa/0x1340 drivers/net/hamradio/mkiss.c:902
> tty_ldisc_receive_buf+0x12f/0x170 drivers/tty/tty_buffer.c:465
> paste_selection+0x346/0x470 drivers/tty/vt/selection.c:389
> tioclinux+0x121/0x530 drivers/tty/vt/vt.c:3055
> vt_ioctl+0x3f1/0x3a30 drivers/tty/vt/vt_ioctl.c:364
This is ioctl(TIOCL_PASTESEL).
Locks held on the path: sel_lock -> termios_rwsem
> other info that might help us debug this:
>
> Chain exists of:
> &tty->termios_rwsem --> console_lock --> sel_lock
Clearly. From the above, we have:
console_lock -> sel_lock
sel_lock -> termios_rwsem
termios_rwsem -> console_lock
Fix this by reversing the console_lock -> sel_lock dependency in
ioctl(TIOCL_SETSEL). First, lock sel_lock, then console_lock.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: syzbot+26183d9746e62da329b8@syzkaller.appspotmail.com
Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200228115406.5735-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We need to nest the console lock in sel_lock, so we have to push it down
a bit. Fortunately, the callers of set_selection_* just lock the console
lock around the function call. So moving it down is easy.
In the next patch, we switch the order.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: 07e6124a1a46 ("vt: selection, close sel_buffer race")
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200228115406.5735-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We want the tty fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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These two were macros. Switch them to static inlines, so that it's more
understandable what they are doing.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Avoid global variables (namely sel_cons) by introducing vc_is_sel. It
checks whether the parameter is the current selection console. This will
help putting sel_cons to a struct later.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Link: https://lore.kernel.org/r/20200219073951.16151-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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syzkaller reported this UAF:
BUG: KASAN: use-after-free in n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741
Read of size 1 at addr ffff8880089e40e9 by task syz-executor.1/13184
CPU: 0 PID: 13184 Comm: syz-executor.1 Not tainted 5.4.7 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014
Call Trace:
...
kasan_report+0xe/0x20 mm/kasan/common.c:634
n_tty_receive_buf_common+0x2481/0x2940 drivers/tty/n_tty.c:1741
tty_ldisc_receive_buf+0xac/0x190 drivers/tty/tty_buffer.c:461
paste_selection+0x297/0x400 drivers/tty/vt/selection.c:372
tioclinux+0x20d/0x4e0 drivers/tty/vt/vt.c:3044
vt_ioctl+0x1bcf/0x28d0 drivers/tty/vt/vt_ioctl.c:364
tty_ioctl+0x525/0x15a0 drivers/tty/tty_io.c:2657
vfs_ioctl fs/ioctl.c:47 [inline]
It is due to a race between parallel paste_selection (TIOCL_PASTESEL)
and set_selection_user (TIOCL_SETSEL) invocations. One uses sel_buffer,
while the other frees it and reallocates a new one for another
selection. Add a mutex to close this race.
The mutex takes care properly of sel_buffer and sel_buffer_lth only. The
other selection global variables (like sel_start, sel_end, and sel_cons)
are protected only in set_selection_user. The other functions need quite
some more work to close the races of the variables there. This is going
to happen later.
This likely fixes (I am unsure as there is no reproducer provided) bug
206361 too. It was marked as CVE-2020-8648.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Reported-by: syzbot+59997e8d5cbdc486e6f6@syzkaller.appspotmail.com
References: https://bugzilla.kernel.org/show_bug.cgi?id=206361
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200210081131.23572-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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When pasting a selection to a vt, the task is set as INTERRUPTIBLE while
waiting for a tty to unthrottle. But signals are not handled at all.
Normally, this is not a problem as tty_ldisc_receive_buf receives all
the goods and a user has no reason to interrupt the task.
There are two scenarios where this matters:
1) when the tty is throttled and a signal is sent to the process, it
spins on a CPU until the tty is unthrottled. schedule() does not
really echedule, but returns immediately, of course.
2) when the sel_buffer becomes invalid, KASAN prevents any reads from it
and the loop simply does not proceed and spins forever (causing the
tty to throttle, but the code never sleeps, the same as above). This
sometimes happens as there is a race in the sel_buffer handling code.
So add signal handling to this ioctl (TIOCL_PASTESEL) and return -EINTR
in case a signal is pending.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200210081131.23572-1-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We need to make sure vc_cons[i].d is not NULL after grabbing
console_lock(), or risk a crash.
general protection fault, probably for non-canonical address 0xdffffc0000000068: 0000 [#1] PREEMPT SMP KASAN
KASAN: null-ptr-deref in range [0x0000000000000340-0x0000000000000347]
CPU: 1 PID: 19462 Comm: syz-executor.5 Not tainted 5.5.0-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:vt_ioctl+0x1f96/0x26d0 drivers/tty/vt/vt_ioctl.c:883
Code: 74 41 e8 bd a6 84 fd 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 e4 04 00 00 48 8b 03 48 8d b8 40 03 00 00 48 89 fa 48 c1 ea 03 <42> 0f b6 14 2a 84 d2 74 09 80 fa 03 0f 8e b1 05 00 00 44 89 b8 40
RSP: 0018:ffffc900086d7bb0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffffff8c34ee88 RCX: ffffc9001415c000
RDX: 0000000000000068 RSI: ffffffff83f0e6e3 RDI: 0000000000000340
RBP: ffffc900086d7cd0 R08: ffff888054ce0100 R09: fffffbfff16a2f6d
R10: ffff888054ce0998 R11: ffff888054ce0100 R12: 000000000000001d
R13: dffffc0000000000 R14: 1ffff920010daf79 R15: 000000000000ff7f
FS: 00007f7d13c12700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd477e3c38 CR3: 0000000095d0a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
tty_ioctl+0xa37/0x14f0 drivers/tty/tty_io.c:2660
vfs_ioctl fs/ioctl.c:47 [inline]
ksys_ioctl+0x123/0x180 fs/ioctl.c:763
__do_sys_ioctl fs/ioctl.c:772 [inline]
__se_sys_ioctl fs/ioctl.c:770 [inline]
__x64_sys_ioctl+0x73/0xb0 fs/ioctl.c:770
do_syscall_64+0xfa/0x790 arch/x86/entry/common.c:294
entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45b399
Code: ad b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f7d13c11c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f7d13c126d4 RCX: 000000000045b399
RDX: 0000000020000080 RSI: 000000000000560a RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000666 R14: 00000000004c7f04 R15: 000000000075bf2c
Modules linked in:
---[ end trace 80970faf7a67eb77 ]---
RIP: 0010:vt_ioctl+0x1f96/0x26d0 drivers/tty/vt/vt_ioctl.c:883
Code: 74 41 e8 bd a6 84 fd 48 89 d8 48 c1 e8 03 42 80 3c 28 00 0f 85 e4 04 00 00 48 8b 03 48 8d b8 40 03 00 00 48 89 fa 48 c1 ea 03 <42> 0f b6 14 2a 84 d2 74 09 80 fa 03 0f 8e b1 05 00 00 44 89 b8 40
RSP: 0018:ffffc900086d7bb0 EFLAGS: 00010202
RAX: 0000000000000000 RBX: ffffffff8c34ee88 RCX: ffffc9001415c000
RDX: 0000000000000068 RSI: ffffffff83f0e6e3 RDI: 0000000000000340
RBP: ffffc900086d7cd0 R08: ffff888054ce0100 R09: fffffbfff16a2f6d
R10: ffff888054ce0998 R11: ffff888054ce0100 R12: 000000000000001d
R13: dffffc0000000000 R14: 1ffff920010daf79 R15: 000000000000ff7f
FS: 00007f7d13c12700(0000) GS:ffff8880ae900000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd477e3c38 CR3: 0000000095d0a000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Cc: stable <stable@vger.kernel.org>
Reported-by: syzbot <syzkaller@googlegroups.com>
Link: https://lore.kernel.org/r/20200210190721.200418-1-edumazet@google.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Commit a6dbe4427559 ("vt: perform safe console erase in the right
order") provided fixes to an earlier commit by gathering all console
scrollback flushing operations in a function of its own. This includes
the invocation of vc_sw->con_switch() as previously done through a
update_screen() call. That commit failed to carry over the
con_is_visible() conditional though, as well as cursor handling, which
caused problems when "\e[3J" was written to a background console.
One could argue for preserving the call to update_screen(). However
this does far more than we need, and it is best to remove scrollback
assumptions from it. Instead let's gather the minimum needed to actually
perform scrollback flushing properly in that one place.
While at it, let's document the vc_sw->con_switch() side effect being
relied upon.
Signed-off-by: Nicolas Pitre <nico@fluxnic.net>
Reported-and-tested-by: Lukas Wunner <lukas@wunner.de>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.2001281205560.1655@knanqh.ubzr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
In old days, the "host-progs" syntax was used for specifying host
programs. It was renamed to the current "hostprogs-y" in 2004.
It is typically useful in scripts/Makefile because it allows Kbuild to
selectively compile host programs based on the kernel configuration.
This commit renames like follows:
always -> always-y
hostprogs-y -> hostprogs
So, scripts/Makefile will look like this:
always-$(CONFIG_BUILD_BIN2C) += ...
always-$(CONFIG_KALLSYMS) += ...
...
hostprogs := $(always-y) $(always-m)
I think this makes more sense because a host program is always a host
program, irrespective of the kernel configuration. We want to specify
which ones to compile by CONFIG options, so always-y will be handier.
The "always", "hostprogs-y", "hostprogs-m" will be kept for backward
compatibility for a while.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
|
|
Commit 3e795de7631b ("[PATCH] VT binding: Add binding/unbinding support
for the VT console") introduced a code comment claiming that
"do_take_over_console is basically a register followed by unbind".
However the function actually performs a register followed by *bind*.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Antonino A. Daplas <adaplas@gmail.com>
Link: https://lore.kernel.org/r/a500f005ba7013ca8165a6d42f59b2183d56114f.1578574427.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Commit c1f5e38a5d35 ("vt: delete unneeded function unbind_con_driver")
removed unbind_con_driver() but retained a comment referencing the
function. Delete it.
Signed-off-by: Lukas Wunner <lukas@wunner.de>
Cc: Wang YanQing <udknight@gmail.com>
Link: https://lore.kernel.org/r/4d77a67d77a1c699e9a6cc3e73044c31c02d60b5.1578574427.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
If the arch setup code hasn't initialized conswitchp yet, set it to
dummy_con in con_init. This will allow us to drop the dummy_con
initialization that's done in almost every architecture.
Signed-off-by: Arvind Sankar <nivedita@alum.mit.edu>
Link: https://lore.kernel.org/r/20191218214506.49252-3-nivedita@alum.mit.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
scripts/conmakehash is only used for generating
drivers/tty/vt/consolemap_deftbl.c
Move it to the related directory.
Signed-off-by: Masahiro Yamada <masahiroy@kernel.org>
Link: https://lore.kernel.org/r/20191217110633.8796-1-masahiroy@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Commit d21b0be246bf ("vt: introduce unicode mode for /dev/vcs") guarded
against using devices containing attributes as this is not yet
implemented. It however failed to guard against writes to any devices
as this is also unimplemented.
Reported-by: Or Cohen <orcohen@paloaltonetworks.com>
Signed-off-by: Nicolas Pitre <npitre@baylibre.com>
Cc: <stable@vger.kernel.org> # v4.19+
Cc: Jiri Slaby <jslaby@suse.com>
Fixes: d21b0be246bf ("vt: introduce unicode mode for /dev/vcs")
Link: https://lore.kernel.org/r/nycvar.YSQ.7.76.1911051030580.30289@knanqh.ubzr
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Do not try to handle keycodes that are too big, otherwise we risk doing
out-of-bounds writes:
BUG: KASAN: global-out-of-bounds in clear_bit include/asm-generic/bitops-instrumented.h:56 [inline]
BUG: KASAN: global-out-of-bounds in kbd_keycode drivers/tty/vt/keyboard.c:1411 [inline]
BUG: KASAN: global-out-of-bounds in kbd_event+0xe6b/0x3790 drivers/tty/vt/keyboard.c:1495
Write of size 8 at addr ffffffff89a1b2d8 by task syz-executor108/1722
...
kbd_keycode drivers/tty/vt/keyboard.c:1411 [inline]
kbd_event+0xe6b/0x3790 drivers/tty/vt/keyboard.c:1495
input_to_handler+0x3b6/0x4c0 drivers/input/input.c:118
input_pass_values.part.0+0x2e3/0x720 drivers/input/input.c:145
input_pass_values drivers/input/input.c:949 [inline]
input_set_keycode+0x290/0x320 drivers/input/input.c:954
evdev_handle_set_keycode_v2+0xc4/0x120 drivers/input/evdev.c:882
evdev_do_ioctl drivers/input/evdev.c:1150 [inline]
In this case we were dealing with a fuzzed HID device that declared over
12K buttons, and while HID layer should not be reporting to us such big
keycodes, we should also be defensive and reject invalid data ourselves as
well.
Reported-by: syzbot+19340dff067c2d3835c0@syzkaller.appspotmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20191122204220.GA129459@dtor-ws
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Not really harmful not to, but also not harm in grabbing the lock. And
this shuts up a new WARNING I introduced in commit ddde3c18b700 ("vt:
More locking checks").
Reported-by: Jens Remus <jremus@linux.ibm.com>
Cc: linux-kernel@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linux-fbdev@vger.kernel.org
Cc: linux-s390@vger.kernel.org
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Martin Hostettler <textshell@uchuujin.de>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Sam Ravnborg <sam@ravnborg.org>
Fixes: ddde3c18b700 ("vt: More locking checks")
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Tested-by: Jens Remus <jremus@linux.ibm.com>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://lore.kernel.org/r/20190718080903.22622-1-daniel.vetter@ffwll.ch
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
I honestly have no idea what the subtle differences between
con_is_visible, con_is_fg (internal to vt.c) and con_is_bound are. But
it looks like both vc->vc_display_fg and con_driver_map are protected
by the console_lock, so probably better if we hold that when checking
this.
To do that I had to deinline the con_is_visible function.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Martin Hostettler <textshell@uchuujin.de>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-5-daniel.vetter@ffwll.ch
|
|
For symmetry reasons with do_unblank_screen, except without the
oops_in_progress special case.
Just a drive-by annotation while I'm trying to untangle the fbcon vs.
fbdev screen blank/unblank maze.
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Adam Borowski <kilobyte@angband.pl>
Cc: Martin Hostettler <textshell@uchuujin.de>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Mikulas Patocka <mpatocka@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190528090304.9388-4-daniel.vetter@ffwll.ch
|
|
After memory allocation failure vc_allocate() doesn't clean up data
which has been initialized in visual_init(). In case of fbcon this
leads to divide-by-0 in fbcon_init() on next open of the same tty.
memory allocation in vc_allocate() may fail here:
1097: vc->vc_screenbuf = kzalloc(vc->vc_screenbuf_size, GFP_KERNEL);
on next open() fbcon_init() skips vc_font.data initialization:
1088: if (!p->fontdata) {
division by zero in fbcon_init() happens here:
1149: new_cols /= vc->vc_font.width;
Additional check is needed in fbcon_deinit() to prevent
usage of uninitialized vc_screenbuf:
1251: if (vc->vc_hi_font_mask && vc->vc_screenbuf)
1252: set_vc_hi_font(vc, false);
Crash:
#6 [ffffc90001eafa60] divide_error at ffffffff81a00be4
[exception RIP: fbcon_init+463]
RIP: ffffffff814b860f RSP: ffffc90001eafb18 RFLAGS: 00010246
...
#7 [ffffc90001eafb60] visual_init at ffffffff8154c36e
#8 [ffffc90001eafb80] vc_allocate at ffffffff8154f53c
#9 [ffffc90001eafbc8] con_install at ffffffff8154f624
...
Signed-off-by: Grzegorz Halat <ghalat@redhat.com>
Reviewed-by: Oleksandr Natalenko <oleksandr@redhat.com>
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty
Pull tty/serial updates from Greg KH:
"Here is the "big" set of tty/serial driver patches for 5.2-rc1.
It's really pretty small, not much happening in this portion of the
kernel at the moment. When the "highlight" is the movement of the
documentation from .txt to .rst files, it's a good merge window.
There's a number of small fixes and updates over the various serial
drivers, and a new "tty null" driver for those embedded systems that
like to make things even smaller and not break things.
All of these have been in linux-next for a while with no reported
issues"
* tag 'tty-5.2-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (45 commits)
tty: serial: add driver for the SiFive UART
dt-bindings: serial: add documentation for the SiFive UART driver
serial: uartps: Add support for cts-override
dt-bindings: xilinx-uartps: Add support for cts-override
serial: milbeaut_usio: Fix error handling in probe and remove
tty: rocket: deprecate the rp_ioctl
tty: rocket: Remove RCPK_GET_STRUCT ioctl
tty: update obsolete termios comment
tty: serial_core: fix error code returned by uart_register_driver()
serial: 8250-mtk: modify baudrate setting
serial: 8250-mtk: add follow control
docs: serial: convert docs to ReST and rename to *.rst
serial: 8250_exar: Adjust IOT2000 matching
TTY: serial_core, add ->install
serial: Fix using plain integer instead of Null pointer
tty:serial_core: Spelling mistake
tty: Add NULL TTY driver
tty: vt: keyboard: Allow Unicode compose base char
Revert "tty: fix NULL pointer issue when tty_port ops is not set"
serial: Add Milbeaut serial control
...
|
|
We want the serial/tty fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
We want the fixes in here as well as this resolves an iio driver merge
issue.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
This patch breaks set_selection() into two functions so that when
called from kernel, copy_from_user() can be avoided. The two functions
are called set_selection_user() and set_selection_kernel() in order to
be explicit about their purposes. This also means updating any
references to set_selection() and fixing for name change. It also
exports set_selection_kernel() and paste_selection().
These changes are used the following patch where speakup's selection
functionality calls into the above functions, thereby doing away with
parallel implementation.
Signed-off-by: Okash Khawaja <okash.khawaja@gmail.com>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
Tested-by: Gregory Nowak <greg@gregn.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
The patch a6dbe4427559 ("vt: perform safe console erase in the right
order") introduced a bug. The conditional do_update_region() was
replaced by a call to update_region() that does contain the conditional
already, but with unwanted extra side effects such as restoring the cursor
drawing.
In order to reproduce the bug:
- use framebuffer console with the AMDGPU driver
- type "links" to start the console www browser
- press 'q' and space to exit links
Now the cursor will be permanently visible in the center of the
screen. It will stay there until something overwrites it.
The bug goes away if we change update_region() back to the conditional
do_update_region().
[ nico: reworded changelog ]
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Reviewed-by: Nicolas Pitre <nico@fluxnic.net>
Cc: stable@vger.kernel.org
Fixes: a6dbe4427559 ("vt: perform safe console erase in the right order")
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Pass Unicode character to k_unicode handler function to honor possible
accent_table definition.
With introduction of KDSKBDIACRUC ioctl, it has been possible to set
compose characters (diacr, base and result) to any Unicode character
(below 0xf000 code point) as defined in struct kbdiacruc.
But it does not work with characters beyond Latin-1 as base, because
they are printed early and not passed to any of the handler functions,
thus breaking compose and dead keys.
It affects keyboard layouts defining such characters on level 1 and
relying on dead keys to access level 3 (e.g., lv-modern with some
modifications for extra characters on level 3 for ē, ā and ī keys).
Signed-off-by: Reinis Danne <rei4dan@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
GIO_UNIMAP can easily result in a high order allocation,
seen 6th order allocation on radeondrmfb:
fbcon: radeondrmfb (fb0) is primary device
Console: switching to colour frame buffer device 160x64
radeon 0000:01:05.0: fb0: radeondrmfb frame buffer device
WARNING: CPU: 0 PID: 78661 at mm/page_alloc.c:3532
__alloc_pages_nodemask+0x1b1/0x600
order 6 >= 3, gfp 0x40d0
The warning is generated by a debug patch.
At the same time it's safe to use kvmalloc() for allocation in
con_get_unimap(), so let's do the substitution.
And do the same for con_set_unimap().
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
There were a few straggling files under drivers/tty/ that did not have
any SPDX identifier either because they entered the tree recently, or
they somehow missed the mass-tagging of commit b24413180f56 ("License
cleanup: add SPDX GPL-2.0 license identifier to files with no license")
This commit follows the same rule as b24413180f56 ("License cleanup: add
SPDX GPL-2.0 license identifier to files with no license") where files
without any specified license in them fall under GPL-2.0 as the correct
license for the individual file. Add that identifier to these remaining
files so that we don't have to guess at the license of them in the
future.
Cc: Jiri Slaby <jslaby@suse.com>
Cc: "David S. Miller" <davem@davemloft.net>
Reviewed-by: Mukesh Ojha <mojha@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Both /dev/vcs and /dev/vcs0 were in use in the past, but these days
/dev/vcs0 is mostly historical curiosity.
* "/dev/vcs" is the name that has always been in the Linux allocated
devices list.
* "vcs" is the device name in sysfs since Linux v2.6.12.
* MAKEDEV(1) in Debian used to create /dev/vcs0 only, but /dev/vcs was
added in 1999: https://bugs.debian.org/45698
* MAKEDEV(1) in RedHat switched from /dev/vcs0 to /dev/vcs in 2000:
* Fri Oct 20 2000 Nalin Dahyabhai <nalin@redhat.com>
- change vcs0 to vcs (ditto for vcsa0)
Signed-off-by: Jakub Wilk <jwilk@jwilk.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Previously, in the userspace, it was possible to use the "setterm" command
from util-linux to blank the VT console by default, using the following
command.
According to the man page,
> The force option keeps the screen blank even if a key is pressed.
It was implemented by calling TIOCL_BLANKSCREEN.
case BLANKSCREEN:
ioctlarg = TIOCL_BLANKSCREEN;
if (ioctl(STDIN_FILENO, TIOCLINUX, &ioctlarg))
warn(_("cannot force blank"));
break;
However, after Linux 4.12, this command ceased to work anymore, which is
unexpected. By inspecting the kernel source, it shows that the issue was
triggered by the side-effect from commit a4199f5eb809 ("tty: Disable
default console blanking interval").
The console blanking is implemented by function do_blank_screen() in vt.c:
"blank_state" will be initialized to "blank_normal_wait" in con_init() if
AND ONLY IF ("blankinterval" > 0). If "blankinterval" is 0, "blank_state"
will be "blank_off" (== 0), and a call to do_blank_screen() will always
abort, even if a forced blanking is required from the user by calling
TIOCL_BLANKSCREEN, the console won't be blanked.
This behavior is unexpected from a user's point-of-view, since it's not
mentioned in any documentation. The setterm man page suggests it will
always work, and the kernel comments in uapi/linux/tiocl.h says
> /* keep screen blank even if a key is pressed */
> #define TIOCL_BLANKSCREEN 14
To fix it, we simply remove the "blank_state != blank_off" check, as
pointed out by Nicolas Pitre, this check doesn't logically make sense
and it's safe to remove.
Suggested-by: Nicolas Pitre <nicolas.pitre@linaro.org>
Fixes: a4199f5eb809 ("tty: Disable default console blanking interval")
Signed-off-by: Yifeng Li <tomli@tomli.me>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
The bug manifests as an attempt to access deallocated memory:
BUG: unable to handle kernel paging request at ffff9c8735448000
#PF error: [PROT] [WRITE]
PGD 288a05067 P4D 288a05067 PUD 288a07067 PMD 7f60c2063 PTE 80000007f5448161
Oops: 0003 [#1] PREEMPT SMP
CPU: 6 PID: 388 Comm: loadkeys Tainted: G C 5.0.0-rc6-00153-g5ded5871030e #91
Hardware name: Gigabyte Technology Co., Ltd. To be filled by O.E.M./H77M-D3H, BIOS F12 11/14/2013
RIP: 0010:__memmove+0x81/0x1a0
Code: 4c 89 4f 10 4c 89 47 18 48 8d 7f 20 73 d4 48 83 c2 20 e9 a2 00 00 00 66 90 48 89 d1 4c 8b 5c 16 f8 4c 8d 54 17 f8 48 c1 e9 03 <f3> 48 a5 4d 89 1a e9 0c 01 00 00 0f 1f 40 00 48 89 d1 4c 8b 1e 49
RSP: 0018:ffffa1b9002d7d08 EFLAGS: 00010203
RAX: ffff9c873541af43 RBX: ffff9c873541af43 RCX: 00000c6f105cd6bf
RDX: 0000637882e986b6 RSI: ffff9c8735447ffb RDI: ffff9c8735447ffb
RBP: ffff9c8739cd3800 R08: ffff9c873b802f00 R09: 00000000fffff73b
R10: ffffffffb82b35f1 R11: 00505b1b004d5b1b R12: 0000000000000000
R13: ffff9c873541af3d R14: 000000000000000b R15: 000000000000000c
FS: 00007f450c390580(0000) GS:ffff9c873f180000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffff9c8735448000 CR3: 00000007e213c002 CR4: 00000000000606e0
Call Trace:
vt_do_kdgkb_ioctl+0x34d/0x440
vt_ioctl+0xba3/0x1190
? __bpf_prog_run32+0x39/0x60
? mem_cgroup_commit_charge+0x7b/0x4e0
tty_ioctl+0x23f/0x920
? preempt_count_sub+0x98/0xe0
? __seccomp_filter+0x67/0x600
do_vfs_ioctl+0xa2/0x6a0
? syscall_trace_enter+0x192/0x2d0
ksys_ioctl+0x3a/0x70
__x64_sys_ioctl+0x16/0x20
do_syscall_64+0x54/0xe0
entry_SYSCALL_64_after_hwframe+0x49/0xbe
The bug manifests on systemd systems with multiple vtcon devices:
# cat /sys/devices/virtual/vtconsole/vtcon0/name
(S) dummy device
# cat /sys/devices/virtual/vtconsole/vtcon1/name
(M) frame buffer device
There systemd runs 'loadkeys' tool in tapallel for each vtcon
instance. This causes two parallel ioctl(KDSKBSENT) calls to
race into adding the same entry into 'func_table' array at:
drivers/tty/vt/keyboard.c:vt_do_kdgkb_ioctl()
The function has no locking around writes to 'func_table'.
The simplest reproducer is to have initrams with the following
init on a 8-CPU machine x86_64:
#!/bin/sh
loadkeys -q windowkeys ru4 &
loadkeys -q windowkeys ru4 &
loadkeys -q windowkeys ru4 &
loadkeys -q windowkeys ru4 &
loadkeys -q windowkeys ru4 &
loadkeys -q windowkeys ru4 &
loadkeys -q windowkeys ru4 &
loadkeys -q windowkeys ru4 &
wait
The change adds lock on write path only. Reads are still racy.
CC: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
CC: Jiri Slaby <jslaby@suse.com>
Link: https://lkml.org/lkml/2019/2/17/256
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
|
|
Commit 4b4ecd9cb853 ("vt: Perform safe console erase only once") removed
what appeared to be an extra call to scr_memsetw(). This missed the fact
that set_origin() must be called before clearing the screen otherwise
old screen content gets restored on the screen when using vgacon. Let's
fix that by moving all the scrollback handling to flush_scrollback()
where it logically belongs, and invoking it before the actual screen
clearing in csi_J(), making the code simpler in the end.
Reported-by: Matthew Whitehead <tedheadster@gmail.com>
Signed-off-by: Nicolas Pitre <nico@linaro.org>
Tested-by: Matthew Whitehead <tedheadster@gmail.com>
Fixes: 4b4ecd9cb853 ("vt: Perform safe console erase only once")
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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We need the tty and serial fixes in here as well.
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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csi sequences can contain subparameters delimited by ':' characters. For
now just ignore the whole sequence in this case. Such sequences are used by
more capable terminal implementations with T.416 high color modes or
extended underline rendition attributes.
Also ignore sequences with private use characters '?', '>', '='
and '>' that are not at the initial position.
Signed-off-by: Martin Hostettler <textshell@uchuujin.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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Various csi sequences contain intermediate characters between the
parameters and the final character. Introduce a additional state that
cleanly ignores these sequences.
This allows the vt to ignore these sequences used by more capable
terminal implementations such as "request mode", etc.
Signed-off-by: Martin Hostettler <textshell@uchuujin.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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