kernel_optimize_test/kernel/printk
John Ogness 59f8bcca1e printk: avoid and/or handle record truncation
If a reader provides a buffer that is smaller than the message text,
the @text_len field of @info will have a value larger than the buffer
size. If readers blindly read @text_len bytes of data without
checking the size, they will read beyond their buffer.

Add this check to record_print_text() to properly recognize when such
truncation has occurred.

Add a maximum size argument to the ringbuffer function to extend
records so that records can not be created that are larger than the
buffer size of readers.

When extending records (LOG_CONT), do not extend records beyond
LOG_LINE_MAX since that is the maximum size available in the buffers
used by consoles and syslog.

Fixes: f5f022e53b ("printk: reimplement log_cont using record extension")
Reported-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Link: https://lore.kernel.org/r/20200930090134.8723-2-john.ogness@linutronix.de
2020-09-30 13:30:28 +02:00
..
braille.c printk: Replace strncmp() with str_has_prefix() 2019-08-16 09:54:08 +02:00
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 printk: Fix preferred console selection with multiple matches 2020-02-18 09:34:42 +01:00
internal.h printk: move dictionary keys to dev_printk_info 2020-09-22 11:27:48 +02:00
Makefile printk: add lockless ringbuffer 2020-07-10 08:48:19 +02:00
printk_ringbuffer.c printk: avoid and/or handle record truncation 2020-09-30 13:30:28 +02:00
printk_ringbuffer.h printk: avoid and/or handle record truncation 2020-09-30 13:30:28 +02:00
printk_safe.c printk: move dictionary keys to dev_printk_info 2020-09-22 11:27:48 +02:00
printk.c printk: avoid and/or handle record truncation 2020-09-30 13:30:28 +02:00