From: Greg Kroah-Hartman Date: Sat, 7 Oct 2023 09:54:43 +0000 (+0200) Subject: 4.14-stable patches X-Git-Tag: v4.14.327~82 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=dbd6d725b106c0c6b9fedbf22b58dd36005a0c46;p=thirdparty%2Fkernel%2Fstable-queue.git 4.14-stable patches added patches: vc_screen-reload-load-of-struct-vc_data-pointer-in-vcs_write-to-avoid-uaf.patch --- diff --git a/queue-4.14/series b/queue-4.14/series index 476681d3d29..9269b0f97f1 100644 --- a/queue-4.14/series +++ b/queue-4.14/series @@ -28,3 +28,4 @@ ata-libata-core-fix-ata_port_request_pm-locking.patch ata-libata-core-fix-port-and-device-removal.patch ata-libata-sata-increase-pmp-srst-timeout-to-10s.patch fs-binfmt_elf_efpic-fix-personality-for-elf-fdpic.patch +vc_screen-reload-load-of-struct-vc_data-pointer-in-vcs_write-to-avoid-uaf.patch diff --git a/queue-4.14/vc_screen-reload-load-of-struct-vc_data-pointer-in-vcs_write-to-avoid-uaf.patch b/queue-4.14/vc_screen-reload-load-of-struct-vc_data-pointer-in-vcs_write-to-avoid-uaf.patch new file mode 100644 index 00000000000..8492348134f --- /dev/null +++ b/queue-4.14/vc_screen-reload-load-of-struct-vc_data-pointer-in-vcs_write-to-avoid-uaf.patch @@ -0,0 +1,117 @@ +From 8fb9ea65c9d1338b0d2bb0a9122dc942cdd32357 Mon Sep 17 00:00:00 2001 +From: George Kennedy +Date: Fri, 12 May 2023 06:08:48 -0500 +Subject: vc_screen: reload load of struct vc_data pointer in vcs_write() to avoid UAF +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +From: George Kennedy + +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 +[ Adjust context due to missing commit + 71d4abfab322 ("vc_screen: rewrite vcs_size to accept vc, not inode") + in 4.14.y stable ] +Signed-off-by: Suraj Jitindar Singh +Signed-off-by: Greg Kroah-Hartman +--- + drivers/tty/vt/vc_screen.c | 11 +++++++++-- + 1 file changed, 9 insertions(+), 2 deletions(-) + +--- a/drivers/tty/vt/vc_screen.c ++++ b/drivers/tty/vt/vc_screen.c +@@ -437,10 +437,17 @@ vcs_write(struct file *file, const char + } + } + +- /* The vcs_size might have changed while we slept to grab +- * the user buffer, so recheck. ++ /* The vc might have been freed or vcs_size might have changed ++ * while we slept to grab the user buffer, so recheck. + * Return data written up to now on failure. + */ ++ vc = vcs_vc(inode, &viewed); ++ if (!vc) { ++ if (written) ++ break; ++ ret = -ENXIO; ++ goto unlock_out; ++ } + size = vcs_size(inode); + if (size < 0) { + if (written)