From 00bb549d7d63a21532e76e4a334d7807a54d9f31 Mon Sep 17 00:00:00 2001 From: Richard Fitzgerald Date: Wed, 27 Mar 2024 11:44:06 +0000 Subject: 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 --- drivers/base/regmap/regcache-maple.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/base') 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); -- cgit v1.2.3