From: Richard Fitzgerald Date: Wed, 27 Mar 2024 11:44:06 +0000 (+0000) Subject: regmap: maple: Fix cache corruption in regcache_maple_drop() X-Git-Tag: v6.9-rc3~11^2~1 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=00bb549d7d63a21532e76e4a334d7807a54d9f31;p=linux-block.git regmap: maple: Fix cache corruption in regcache_maple_drop() 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 Fixes: f033c26de5a5 ("regmap: Add maple tree based register cache") Link: https://msgid.link/r/20240327114406.976986-1-rf@opensource.cirrus.com Signed-off-by: Mark Brown --- diff --git a/drivers/base/regmap/regcache-maple.c b/drivers/base/regmap/regcache-maple.c index 41edd6a430eb..c1776127a572 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);