6.6-stable review patch. If anyone has any objections, please let me know.
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From: Richard Fitzgerald rf@opensource.cirrus.com
[ 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@opensource.cirrus.com 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 broonie@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/base/regmap/regcache-maple.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
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);