Tetsuo Handa e80c1a9d5f printk: fix printk_time race. ... Since printk_time can be toggled via /sys/module/printk/parameters/time , it is not safe to assume that output length does not change across multiple msg_print_text() calls. If we hit this race, we can observe failures such as SYSLOG_ACTION_READ_ALL writes more bytes than userspace has supplied, SYSLOG_ACTION_SIZE_UNREAD returns -EFAULT when succeeded, SYSLOG_ACTION_READ reads garbage memory or even triggers an kernel oops at _copy_to_user() due to integer overflow. To close this race, get a snapshot value of printk_time and pass it to SYSLOG_ACTION_READ, SYSLOG_ACTION_READ_ALL, SYSLOG_ACTION_SIZE_UNREAD and kmsg_dump_get_buffer(). Link: http://lkml.kernel.org/r/555af37c-b9e0-f940-cb73-a78eba2d4944@i-love.sakura.ne.jp To: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com> Signed-off-by: Petr Mladek <pmladek@suse.com>		2018-12-10 10:45:59 +01:00
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braille.c	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
braille.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
console_cmdline.h	License cleanup: add SPDX GPL-2.0 license identifier to files with no license	2017-11-02 11:10:55 +01:00
internal.h	printk/nmi: Prevent deadlock when accessing the main log buffer in NMI	2018-07-09 14:10:40 +02:00
Makefile	printk: introduce per-cpu safe_print seq buffer	2017-02-08 11:07:11 +01:00
printk_safe.c	printk/tracing: Do not trace printk_nmi_enter()	2018-09-06 11:24:05 -04:00
printk.c	printk: fix printk_time race.	2018-12-10 10:45:59 +01:00