This is a note to let you know that I've just added the patch titled
regmap: maple: Fix cache corruption in regcache_maple_drop()
to the 6.8-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
regmap-maple-fix-cache-corruption-in-regcache_maple_.patch
and it can be found in the queue-6.8 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 5d8ac6fd9d36152f5ff13a69877099ab3e7546b2
Author: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
Date: Wed Mar 27 11:44:06 2024 +0000
regmap: maple: Fix cache corruption in regcache_maple_drop()
[ Upstream commit 00bb549d7d63a21532e76e4a334d7807a54d9f31 ]
When keeping the upper end of a cache block entry, the entry[] array
must be indexed by the offset from the base register of the block,
i.e. max - mas.index.
The code was indexing entry[] by only the register address, leading
to an out-of-bounds access that copied some part of the kernel
memory over the cache contents.
This bug was not detected by the regmap KUnit test because it only
tests with a block of registers starting at 0, so mas.index == 0.
Signed-off-by: Richard Fitzgerald <rf@xxxxxxxxxxxxxxxxxxxxx>
Fixes: f033c26de5a5 ("regmap: Add maple tree based register cache")
Link: https://msgid.link/r/20240327114406.976986-1-rf@xxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Mark Brown <broonie@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/base/regmap/regcache-maple.c b/drivers/base/regmap/regcache-maple.c
index 41edd6a430eb4..c1776127a5724 100644
--- a/drivers/base/regmap/regcache-maple.c
+++ b/drivers/base/regmap/regcache-maple.c
@@ -145,7 +145,7 @@ static int regcache_maple_drop(struct regmap *map, unsigned int min,
upper_index = max + 1;
upper_last = mas.last;
- upper = kmemdup(&entry[max + 1],
+ upper = kmemdup(&entry[max - mas.index + 1],
((mas.last - max) *
sizeof(unsigned long)),
map->alloc_flags);
