linux/fs/pstore
Kees Cook 89d328f637 pstore/ram: Correctly calculate usable PRZ bytes
The actual number of bytes stored in a PRZ is smaller than the
bytes requested by platform data, since there is a header on each
PRZ. Additionally, if ECC is enabled, there are trailing bytes used
as well. Normally this mismatch doesn't matter since PRZs are circular
buffers and the leading "overflow" bytes are just thrown away. However, in
the case of a compressed record, this rather badly corrupts the results.

This corruption was visible with "ramoops.mem_size=204800 ramoops.ecc=1".
Any stored crashes would not be uncompressable (producing a pstorefs
"dmesg-*.enc.z" file), and triggering errors at boot:

  [    2.790759] pstore: crypto_comp_decompress failed, ret = -22!

Backporting this depends on commit 70ad35db33 ("pstore: Convert console
write to use ->write_buf")

Reported-by: Joel Fernandes <joel@joelfernandes.org>
Fixes: b0aad7a99c ("pstore: Add compression support to pstore")
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
2018-11-29 13:46:43 -08:00
..
ftrace.c pstore: Remove write_buf() callback 2017-03-07 14:01:02 -08:00
inode.c pstore: Centralize init/exit routines 2018-10-22 07:11:58 -07:00
internal.h pstore: Centralize init/exit routines 2018-10-22 07:11:58 -07:00
Kconfig pstore: add zstd compression support 2018-08-03 18:12:18 -07:00
Makefile License cleanup: add SPDX GPL-2.0 license identifier to files with no license 2017-11-02 11:10:55 +01:00
platform.c pstore: Refactor compression initialization 2018-10-22 07:11:58 -07:00
pmsg.c pstore: Create common record initializer 2017-05-31 10:13:44 -07:00
ram_core.c pstore/ram: Clarify resource reservation labels 2018-10-22 07:11:58 -07:00
ram.c pstore/ram: Correctly calculate usable PRZ bytes 2018-11-29 13:46:43 -08:00