Enlin Mu 25fb4e3402 pstore/ram: Check start of empty przs during init ... commit fe8c3623ab upstream. After commit 30696378f6 ("pstore/ram: Do not treat empty buffers as valid"), initialization would assume a prz was valid after seeing that the buffer_size is zero (regardless of the buffer start position). This unchecked start value means it could be outside the bounds of the buffer, leading to future access panics when written to: sysdump_panic_event+0x3b4/0x5b8 atomic_notifier_call_chain+0x54/0x90 panic+0x1c8/0x42c die+0x29c/0x2a8 die_kernel_fault+0x68/0x78 __do_kernel_fault+0x1c4/0x1e0 do_bad_area+0x40/0x100 do_translation_fault+0x68/0x80 do_mem_abort+0x68/0xf8 el1_da+0x1c/0xc0 __raw_writeb+0x38/0x174 __memcpy_toio+0x40/0xac persistent_ram_update+0x44/0x12c persistent_ram_write+0x1a8/0x1b8 ramoops_pstore_write+0x198/0x1e8 pstore_console_write+0x94/0xe0 ... To avoid this, also check if the prz start is 0 during the initialization phase. If not, the next prz sanity check case will discover it (start > size) and zap the buffer back to a sane state. Fixes: 30696378f6 ("pstore/ram: Do not treat empty buffers as valid") Cc: Yunlong Xing <yunlong.xing@unisoc.com> Cc: stable@vger.kernel.org Signed-off-by: Enlin Mu <enlin.mu@unisoc.com> Link: https://lore.kernel.org/r/20230801060432.1307717-1-yunlong.xing@unisoc.com [kees: update commit log with backtrace and clarifications] Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>		2023-09-13 09:53:55 +02:00
..
blk.c	init: improve the name_to_dev_t interface	2023-06-05 10:56:46 -06:00
ftrace.c	pstore/ftrace: Allow immediate recording	2021-11-18 10:29:52 -08:00
inode.c	pstore: Add priv field to pstore_record for backend specific use	2022-06-24 20:40:04 +02:00
internal.h	pstore: Move kmsg_bytes default into Kconfig	2020-12-01 12:09:17 -08:00
Kconfig	pstore: Make sure CONFIG_PSTORE_PMSG selects CONFIG_RT_MUTEXES	2022-12-23 10:33:27 -08:00
Makefile	pstore/blk: Introduce backend for block devices	2020-05-30 10:34:03 -07:00
platform.c	pstore: Alert on backend write error	2022-10-19 09:25:39 -07:00
pmsg.c	pstore update for v6.4-rc1	2023-04-27 17:03:40 -07:00
ram_core.c	pstore/ram: Check start of empty przs during init	2023-09-13 09:53:55 +02:00
ram_internal.h	pstore/ram: Set freed addresses to NULL	2022-10-19 09:25:39 -07:00
ram.c	pstore/ram: Convert to platform remove callback returning void	2023-05-10 14:06:00 -07:00
zone.c	pstore/zone: Use GFP_ATOMIC to allocate zone buffer	2022-10-17 13:14:10 -07:00