commit 7127d24372bf23675a36edc64d092dc7fd92ebe8 upstream.
init_r_port can access pc104 array out of bounds. pc104 is a 2D array
defined to have 4 members. Each member has 8 submembers.
* we can have more than 4 (PCI) boards, i.e. [board] can be OOB
* line is not modulo-ed by anything, so the first line on the second
board can be 4, on the 3rd 12 or alike (depending on previously
registered boards). It's zero only on the first line of the first
board. So even [line] can be OOB, quite soon (with the 2nd registered
board already).
This code is broken for ages, so just avoid the OOB accesses and don't
try to fix it as we would need to find out the correct line number. Use
the default: RS232, if we are out.
Generally, if anyone needs to set the interface types, a module parameter
is past the last thing that should be used for this purpose. The
parameters' description says it's for ISA cards anyway.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: stable <stable@vger.kernel.org>
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Link: https://lore.kernel.org/r/20200417105959.15201-2-jslaby@suse.cz
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 9a9fc42b86c06120744555fea43fdcabe297c656 upstream. If there is a lot(more then 16) of virtio-console devices or virtio_console module is reloaded - buffers 'vtermnos' and 'cons_ops' are overflowed. In older kernels it overruns spinlock which leads to kernel freezing: https://bugzilla.redhat.com/show_bug.cgi?id=1786239 To reproduce the issue, you can try simple script that loads/unloads module. Something like this: while [ 1 ] do modprobe virtio_console sleep 2 modprobe -r virtio_console sleep 2 done Description of problem: Guest get 'Call Trace' when loading module "virtio_console" and unloading it frequently - clearly reproduced on kernel-4.18.0: [ 81.498208] ------------[ cut here ]------------ [ 81.499263] pvqspinlock: lock 0xffffffff92080020 has corrupted value 0xc0774ca0! [ 81.501000] WARNING: CPU: 0 PID: 785 at kernel/locking/qspinlock_paravirt.h:500 __pv_queued_spin_unlock_slowpath+0xc0/0xd0 [ 81.503173] Modules linked in: virtio_console fuse xt_CHECKSUM ipt_MASQUERADE xt_conntrack ipt_REJECT nft_counter nf_nat_tftp nft_objref nf_conntrack_tftp tun bridge stp llc nft_fib_inet nft_fib_ipv4 nft_fib_ipv6 nft_fib nft_reject_inet nf_reject_ipv4 nf_reject_ipv6 nft_reject nft_ct nf_tables_set nft_chain_nat_ipv6 nf_conntrack_ipv6 nf_defrag_ipv6 nf_nat_ipv6 nft_chain_route_ipv6 nft_chain_nat_ipv4 nf_conntrack_ipv4 nf_defrag_ipv4 nf_nat_ipv4 nf_nat nf_conntrack nft_chain_route_ipv4 ip6_tables nft_compat ip_set nf_tables nfnetlink sunrpc bochs_drm drm_vram_helper ttm drm_kms_helper syscopyarea sysfillrect sysimgblt fb_sys_fops drm i2c_piix4 pcspkr crct10dif_pclmul crc32_pclmul joydev ghash_clmulni_intel ip_tables xfs libcrc32c sd_mod sg ata_generic ata_piix virtio_net libata crc32c_intel net_failover failover serio_raw virtio_scsi dm_mirror dm_region_hash dm_log dm_mod [last unloaded: virtio_console] [ 81.517019] CPU: 0 PID: 785 Comm: kworker/0:2 Kdump: loaded Not tainted 4.18.0-167.el8.x86_64 #1 [ 81.518639] Hardware name: Red Hat KVM, BIOS 1.12.0-5.scrmod+el8.2.0+5159+d8aa4d83 04/01/2014 [ 81.520205] Workqueue: events control_work_handler [virtio_console] [ 81.521354] RIP: 0010:__pv_queued_spin_unlock_slowpath+0xc0/0xd0 [ 81.522450] Code: 07 00 48 63 7a 10 e8 bf 64 f5 ff 66 90 c3 8b 05 e6 cf d6 01 85 c0 74 01 c3 8b 17 48 89 fe 48 c7 c7 38 4b 29 91 e8 3a 6c fa ff <0f> 0b c3 0f 0b 90 90 90 90 90 90 90 90 90 90 90 0f 1f 44 00 00 48 [ 81.525830] RSP: 0018:ffffb51a01ffbd70 EFLAGS: 00010282 [ 81.526798] RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000000 [ 81.528110] RDX: ffff9e66f1826480 RSI: ffff9e66f1816a08 RDI: ffff9e66f1816a08 [ 81.529437] RBP: ffffffff9153ff10 R08: 000000000000026c R09: 0000000000000053 [ 81.530732] R10: 0000000000000000 R11: ffffb51a01ffbc18 R12: ffff9e66cd682200 [ 81.532133] R13: ffffffff9153ff10 R14: ffff9e6685569500 R15: ffff9e66cd682000 [ 81.533442] FS: 0000000000000000(0000) GS:ffff9e66f1800000(0000) knlGS:0000000000000000 [ 81.534914] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 81.535971] CR2: 00005624c55b14d0 CR3: 00000003a023c000 CR4: 00000000003406f0 [ 81.537283] Call Trace: [ 81.537763] __raw_callee_save___pv_queued_spin_unlock_slowpath+0x11/0x20 [ 81.539011] .slowpath+0x9/0xe [ 81.539585] hvc_alloc+0x25e/0x300 [ 81.540237] init_port_console+0x28/0x100 [virtio_console] [ 81.541251] handle_control_message.constprop.27+0x1c4/0x310 [virtio_console] [ 81.542546] control_work_handler+0x70/0x10c [virtio_console] [ 81.543601] process_one_work+0x1a7/0x3b0 [ 81.544356] worker_thread+0x30/0x390 [ 81.545025] ? create_worker+0x1a0/0x1a0 [ 81.545749] kthread+0x112/0x130 [ 81.546358] ? kthread_flush_work_fn+0x10/0x10 [ 81.547183] ret_from_fork+0x22/0x40 [ 81.547842] ---[ end trace aa97649bd16c8655 ]--- [ 83.546539] general protection fault: 0000 [#1] SMP NOPTI [ 83.547422] CPU: 5 PID: 3225 Comm: modprobe Kdump: loaded Tainted: G W --------- - - 4.18.0-167.el8.x86_64 #1 [ 83.549191] Hardware name: Red Hat KVM, BIOS 1.12.0-5.scrmod+el8.2.0+5159+d8aa4d83 04/01/2014 [ 83.550544] RIP: 0010:__pv_queued_spin_lock_slowpath+0x19a/0x2a0 [ 83.551504] Code: c4 c1 ea 12 41 be 01 00 00 00 4c 8d 6d 14 41 83 e4 03 8d 42 ff 49 c1 e4 05 48 98 49 81 c4 40 a5 02 00 4c 03 24 c5 60 48 34 91 <49> 89 2c 24 b8 00 80 00 00 eb 15 84 c0 75 0a 41 0f b6 54 24 14 84 [ 83.554449] RSP: 0018:ffffb51a0323fdb0 EFLAGS: 00010202 [ 83.555290] RAX: 000000000000301c RBX: ffffffff92080020 RCX: 0000000000000001 [ 83.556426] RDX: 000000000000301d RSI: 0000000000000000 RDI: 0000000000000000 [ 83.557556] RBP: ffff9e66f196a540 R08: 000000000000028a R09: ffff9e66d2757788 [ 83.558688] R10: 0000000000000000 R11: 0000000000000000 R12: 646e61725f770b07 [ 83.559821] R13: ffff9e66f196a554 R14: 0000000000000001 R15: 0000000000180000 [ 83.560958] FS: 00007fd5032e8740(0000) GS:ffff9e66f1940000(0000) knlGS:0000000000000000 [ 83.562233] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 83.563149] CR2: 00007fd5022b0da0 CR3: 000000038c334000 CR4: 00000000003406e0 Signed-off-by: Andrew Melnychenko <andrew@daynix.com> Cc: stable <stable@vger.kernel.org> Link: https://lore.kernel.org/r/20200414191503.3471783-1-andrew@daynix.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 3670664b5da555a2a481449b3baafff113b0ac35 upstream.
ev_byte_channel_send() assumes that its third argument is a 16 byte
array. Some places where it is called it may not be (or we can't
easily tell if it is). Newer compilers have started producing warnings
about this, so make sure we actually pass a 16 byte array.
There may be more elegant solutions to this, but the driver is quite
old and hasn't been updated in many years.
The warnings (from a powerpc allyesconfig build) are:
In file included from include/linux/byteorder/big_endian.h:5,
from arch/powerpc/include/uapi/asm/byteorder.h:14,
from include/asm-generic/bitops/le.h:6,
from arch/powerpc/include/asm/bitops.h:250,
from include/linux/bitops.h:29,
from include/linux/kernel.h:12,
from include/asm-generic/bug.h:19,
from arch/powerpc/include/asm/bug.h:109,
from include/linux/bug.h:5,
from include/linux/mmdebug.h:5,
from include/linux/gfp.h:5,
from include/linux/slab.h:15,
from drivers/tty/ehv_bytechan.c:24:
drivers/tty/ehv_bytechan.c: In function ‘ehv_bc_udbg_putc’:
arch/powerpc/include/asm/epapr_hcalls.h:298:20: warning: array subscript 1 is outside array bounds of ‘const char[1]’ [-Warray-bounds]
298 | r6 = be32_to_cpu(p[1]);
include/uapi/linux/byteorder/big_endian.h:40:51: note: in definition of macro ‘__be32_to_cpu’
40 | #define __be32_to_cpu(x) ((__force __u32)(__be32)(x))
| ^
arch/powerpc/include/asm/epapr_hcalls.h:298:7: note: in expansion of macro ‘be32_to_cpu’
298 | r6 = be32_to_cpu(p[1]);
| ^~~~~~~~~~~
drivers/tty/ehv_bytechan.c:166:13: note: while referencing ‘data’
166 | static void ehv_bc_udbg_putc(char c)
| ^~~~~~~~~~~~~~~~
Fixes: dcd83aaff1c8 ("tty/powerpc: introduce the ePAPR embedded hypervisor byte channel driver")
Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au>
Tested-by: Laurentiu Tudor <laurentiu.tudor@nxp.com>
[mpe: Trim warnings from change log]
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20200109183912.5fcb52aa@canb.auug.org.au
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 7cf64b18b0b96e751178b8d0505d8466ff5a448f upstream.
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>
commit ca4463bf8438b403596edd0ec961ca0d4fbe0220 upstream.
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>
commit 1aa6e058dd6cd04471b1f21298270014daf48ac9 upstream. 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>
commit f400991bf872debffb01c46da882dc97d7e3248e upstream. 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>
commit e587e8f17433ddb26954f0edf5b2f95c42155ae9 upstream. 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>
commit dce05aa6eec977f1472abed95ccd71276b9a3864 upstream. 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> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit e8c75a30a23c6ba63f4ef6895cbf41fd42f21aa2 upstream.
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>