kernel/linux.git/drivers/tty/vt, branch v6.1.124

vt: prevent kernel-infoleak in con_font_get()

2024-11-08T15:26:48+00:00

commit f956052e00de211b5c9ebaa1958366c23f82ee9e upstream. font.data may not initialize all memory spaces depending on the implementation of vc->vc_sw->con_font_get. This may cause info-leak, so to prevent this, it is safest to modify it to initialize the allocated memory space to 0, and it generally does not affect the overall performance of the system. Cc: stable@vger.kernel.org Reported-by: syzbot+955da2d57931604ee691@syzkaller.appspotmail.com Fixes: 05e2600cb0a4 ("VT: Bump font size limitation to 64x128 pixels") Signed-off-by: Jeongjun Park Link: https://lore.kernel.org/r/20241010174619.59662-1-aha310510@gmail.com Signed-off-by: Greg Kroah-Hartman

tty: add the option to have a tty reject a new ldisc

2024-06-27T11:46:17+00:00

[ Upstream commit 6bd23e0c2bb6c65d4f5754d1456bc9a4427fc59b ] ... and use it to limit the virtual terminals to just N_TTY. They are kind of special, and in particular, the "con_write()" routine violates the "writes cannot sleep" rule that some ldiscs rely on. This avoids the BUG: sleeping function called from invalid context at kernel/printk/printk.c:2659 when N_GSM has been attached to a virtual console, and gsmld_write() calls con_write() while holding a spinlock, and con_write() then tries to get the console lock. Tested-by: Tetsuo Handa Cc: Jiri Slaby Cc: Andrew Morton Cc: Daniel Starke Reported-by: syzbot Closes: https://syzkaller.appspot.com/bug?extid=dbac96d8e73b61aa559c Signed-off-by: Linus Torvalds Link: https://lore.kernel.org/r/20240423163339.59780-1-torvalds@linux-foundation.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

vt: fix unicode buffer corruption when deleting characters

2024-04-03T13:19:42+00:00

commit 1581dafaf0d34bc9c428a794a22110d7046d186d upstream. This is the same issue that was fixed for the VGA text buffer in commit 39cdb68c64d8 ("vt: fix memory overlapping when deleting chars in the buffer"). The cure is also the same i.e. replace memcpy() with memmove() due to the overlaping buffers. Signed-off-by: Nicolas Pitre Fixes: 81732c3b2fed ("tty vt: Fix line garbage in virtual console on command line edition") Cc: stable Link: https://lore.kernel.org/r/sn184on2-3p0q-0qrq-0218-895349s4753o@syhkavp.arg Signed-off-by: Greg Kroah-Hartman

tty: vt: fix 20 vs 0x20 typo in EScsiignore

2024-03-26T22:20:57+00:00

[ Upstream commit 0e6a92f67c8a94707f7bb27ac29e2bdf3e7c167d ] The if (c >= 20 && c <= 0x3f) test added in commit 7a99565f8732 is wrong. 20 is DC4 in ascii and it makes no sense to consider that as the bottom limit. Instead, it should be 0x20 as in the other test in the commit above. This is supposed to NOT change anything as we handle interesting 20-0x20 asciis far before this if. So for sakeness, change to 0x20 (which is SPACE). Signed-off-by: "Jiri Slaby (SUSE)" Fixes: 7a99565f8732 ("vt: ignore csi sequences with intermediate characters.") Cc: Martin Hostettler Link: https://lore.kernel.org/all/ZaP45QY2WEsDqoxg@neutronstar.dyndns.org/ Tested-by: Helge Deller # parisc STI console Link: https://lore.kernel.org/r/20240122110401.7289-4-jirislaby@kernel.org Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF

2023-05-24T16:32:51+00:00

commit 8fb9ea65c9d1338b0d2bb0a9122dc942cdd32357 upstream. After a call to console_unlock() in vcs_write() the vc_data struct can be freed by vc_port_destruct(). Because of that, the struct vc_data pointer must be reloaded in the while loop in vcs_write() after console_lock() to avoid a UAF when vcs_size() is called. Syzkaller reported a UAF in vcs_size(). BUG: KASAN: slab-use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215) Read of size 4 at addr ffff8880beab89a8 by task repro_vcs_size/4119 Call Trace: __asan_report_load4_noabort (mm/kasan/report_generic.c:380) vcs_size (drivers/tty/vt/vc_screen.c:215) vcs_write (drivers/tty/vt/vc_screen.c:664) vfs_write (fs/read_write.c:582 fs/read_write.c:564) ... Allocated by task 1213: kmalloc_trace (mm/slab_common.c:1064) vc_allocate (./include/linux/slab.h:559 ./include/linux/slab.h:680 drivers/tty/vt/vt.c:1078 drivers/tty/vt/vt.c:1058) con_install (drivers/tty/vt/vt.c:3334) tty_init_dev (drivers/tty/tty_io.c:1303 drivers/tty/tty_io.c:1415 drivers/tty/tty_io.c:1392) tty_open (drivers/tty/tty_io.c:2082 drivers/tty/tty_io.c:2128) chrdev_open (fs/char_dev.c:415) do_dentry_open (fs/open.c:921) vfs_open (fs/open.c:1052) ... Freed by task 4116: kfree (mm/slab_common.c:1016) vc_port_destruct (drivers/tty/vt/vt.c:1044) tty_port_destructor (drivers/tty/tty_port.c:296) tty_port_put (drivers/tty/tty_port.c:312) vt_disallocate_all (drivers/tty/vt/vt_ioctl.c:662 (discriminator 2)) vt_ioctl (drivers/tty/vt/vt_ioctl.c:903) tty_ioctl (drivers/tty/tty_io.c:2778) ... The buggy address belongs to the object at ffff8880beab8800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 424 bytes inside of freed 1024-byte region [ffff8880beab8800, ffff8880beab8c00) The buggy address belongs to the physical page: page:00000000afc77580 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0xbeab8 head:00000000afc77580 order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) page_type: 0xffffffff() raw: 000fffffc0010200 ffff888100042dc0 ffffea000426de00 dead000000000002 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880beab8880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880beab8900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880beab8980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880beab8a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880beab8a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Disabling lock debugging due to kernel taint Fixes: ac751efa6a0d ("console: rename acquire/release_console_sem() to console_lock/unlock()") Cc: stable Reported-by: syzkaller Signed-off-by: George Kennedy Reviewed-by: Thomas Weißschuh Link: https://lore.kernel.org/r/1683889728-10411-1-git-send-email-george.kennedy@oracle.com Signed-off-by: Greg Kroah-Hartman

vc_screen: modify vcs_size() handling in vcs_read()

2023-03-11T12:55:29+00:00

[ Upstream commit 46d733d0efc79bc8430d63b57ab88011806d5180 ] Restore the vcs_size() handling in vcs_read() to what it had been in previous version. Fixes: 226fae124b2d ("vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF") Suggested-by: Jiri Slaby Signed-off-by: George Kennedy Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin

vc_screen: don't clobber return value in vcs_read

2023-03-03T10:52:23+00:00

commit ae3419fbac845b4d3f3a9fae4cc80c68d82cdf6e upstream. Commit 226fae124b2d ("vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF") moved the call to vcs_vc() into the loop. While doing this it also moved the unconditional assignment of ret = -ENXIO; This unconditional assignment was valid outside the loop but within it it clobbers the actual value of ret. To avoid this only assign "ret = -ENXIO" when actually needed. [ Also, the 'goto unlock_out" needs to be just a "break", so that it does the right thing when it exits on later iterations when partial success has happened - Linus ] Reported-by: Storm Dragon Link: https://lore.kernel.org/lkml/Y%2FKS6vdql2pIsCiI@hotmail.com/ Fixes: 226fae124b2d ("vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF") Signed-off-by: Thomas Weißschuh Link: https://lore.kernel.org/lkml/64981d94-d00c-4b31-9063-43ad0a384bde@t-8ch.de/ Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

vc_screen: move load of struct vc_data pointer in vcs_read() to avoid UAF

2023-02-09T10:28:14+00:00

[ Upstream commit 226fae124b2dac217ea5436060d623ff3385bc34 ] After a call to console_unlock() in vcs_read() the vc_data struct can be freed by vc_deallocate(). Because of that, the struct vc_data pointer load must be done at the top of while loop in vcs_read() to avoid a UAF when vcs_size() is called. Syzkaller reported a UAF in vcs_size(). BUG: KASAN: use-after-free in vcs_size (drivers/tty/vt/vc_screen.c:215) Read of size 4 at addr ffff8881137479a8 by task 4a005ed81e27e65/1537 CPU: 0 PID: 1537 Comm: 4a005ed81e27e65 Not tainted 6.2.0-rc5 #1 Hardware name: Red Hat KVM, BIOS 1.15.0-2.module Call Trace: __asan_report_load4_noabort (mm/kasan/report_generic.c:350) vcs_size (drivers/tty/vt/vc_screen.c:215) vcs_read (drivers/tty/vt/vc_screen.c:415) vfs_read (fs/read_write.c:468 fs/read_write.c:450) ... Allocated by task 1191: ... kmalloc_trace (mm/slab_common.c:1069) vc_allocate (./include/linux/slab.h:580 ./include/linux/slab.h:720 drivers/tty/vt/vt.c:1128 drivers/tty/vt/vt.c:1108) con_install (drivers/tty/vt/vt.c:3383) tty_init_dev (drivers/tty/tty_io.c:1301 drivers/tty/tty_io.c:1413 drivers/tty/tty_io.c:1390) tty_open (drivers/tty/tty_io.c:2080 drivers/tty/tty_io.c:2126) chrdev_open (fs/char_dev.c:415) do_dentry_open (fs/open.c:883) vfs_open (fs/open.c:1014) ... Freed by task 1548: ... kfree (mm/slab_common.c:1021) vc_port_destruct (drivers/tty/vt/vt.c:1094) tty_port_destructor (drivers/tty/tty_port.c:296) tty_port_put (drivers/tty/tty_port.c:312) vt_disallocate_all (drivers/tty/vt/vt_ioctl.c:662 (discriminator 2)) vt_ioctl (drivers/tty/vt/vt_ioctl.c:903) tty_ioctl (drivers/tty/tty_io.c:2776) ... The buggy address belongs to the object at ffff888113747800 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 424 bytes inside of 1024-byte region [ffff888113747800, ffff888113747c00) The buggy address belongs to the physical page: page:00000000b3fe6c7c refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x113740 head:00000000b3fe6c7c order:3 compound_mapcount:0 subpages_mapcount:0 compound_pincount:0 anon flags: 0x17ffffc0010200(slab|head|node=0|zone=2|lastcpupid=0x1fffff) raw: 0017ffffc0010200 ffff888100042dc0 0000000000000000 dead000000000001 raw: 0000000000000000 0000000000100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff888113747880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113747900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb > ffff888113747980: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff888113747a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff888113747a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Disabling lock debugging due to kernel taint Fixes: ac751efa6a0d ("console: rename acquire/release_console_sem() to console_lock/unlock()") Reported-by: syzkaller Suggested-by: Jiri Slaby Signed-off-by: George Kennedy Link: https://lore.kernel.org/r/1674577014-12374-1-git-send-email-george.kennedy@oracle.com Signed-off-by: Greg Kroah-Hartman Signed-off-by: Sasha Levin

Merge 6.0-rc4 into tty-next

2022-09-05T05:59:28+00:00

We need the tty/serial fixes in here as well. Signed-off-by: Greg Kroah-Hartman

tty/vt: Add console_lock check to vt_console_print()

2022-09-01T14:58:08+00:00

I'm scratching my head why we have this printing_lock. Digging through historical git trees shows that: - Added in 1.1.73, and I found absolutely no reason why. - Converted to atomic bitops in 2.1.125pre2, I guess as part of SMP enabling/bugfixes. - Converted to a proper spinlock in b0940003f25d ("vt: bitlock fix") because the hand-rolled atomic version lacked necessary memory barriers. Digging around in lore for that time period did also not shed further light. The only reason I think this might still be relevant today is that (to my understanding at least, ymmv) during an oops we might be printing without console_lock held. See console_flush_on_panic() and the comments in there - we flush out the console buffers irrespective of whether we managed to acquire the right locks. The strange thing is that this reason is fairly recent, because the console flushing was historically done without oops_in_progress set. This only changed in c7c3f05e341a ("panic: avoid deadlocks in re-entrant console drivers"), which removed the call to bust_spinlocks(0) (which decrements oops_in_progress again) before flushing out the console (which back then was open coded as a console_trylock/unlock pair). Note that this entire mess should be properly fixed in the printk/console layer, and not inflicted on each implementation. For now just document what's going on and check that in all other cases callers obey the locking rules. v2: WARN_CONSOLE_UNLOCKED already checks for oops_in_progress (something else that should be fixed I guess), hence remove the open-coded check I've had. Signed-off-by: Daniel Vetter Cc: Greg Kroah-Hartman Cc: Jiri Slaby Cc: "Ilpo Järvinen" Cc: Daniel Vetter Cc: Xuezhi Zhang Cc: Yangxi Xiang Cc: Tetsuo Handa Cc: nick black Cc: Petr Mladek Cc: Sergey Senozhatsky Cc: Steven Rostedt Cc: John Ogness Reviewed-by: Sam Ravnborg Link: https://lore.kernel.org/r/20220830144945.430528-1-daniel.vetter@ffwll.ch Signed-off-by: Greg Kroah-Hartman