From: Yang Yingliang yangyingliang@huawei.com

stable inclusion from stable-v4.19.215 commit 3dae1a4eced3ee733d7222e69b8a55caf2d61091 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/I9RD9Z CVE: CVE-2021-47483

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=...

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commit 55e6d8037805b3400096d621091dfbf713f97e83 upstream.

In regcache_rbtree_insert_to_block(), when 'present' realloc failed, the 'blk' which is supposed to assign to 'rbnode->block' will be freed, so 'rbnode->block' points a freed memory, in the error handling path of regcache_rbtree_init(), 'rbnode->block' will be freed again in regcache_rbtree_exit(), KASAN will report double-free as follows:

BUG: KASAN: double-free or invalid-free in kfree+0xce/0x390 Call Trace: slab_free_freelist_hook+0x10d/0x240 kfree+0xce/0x390 regcache_rbtree_exit+0x15d/0x1a0 regcache_rbtree_init+0x224/0x2c0 regcache_init+0x88d/0x1310 __regmap_init+0x3151/0x4a80 __devm_regmap_init+0x7d/0x100 madera_spi_probe+0x10f/0x333 [madera_spi] spi_probe+0x183/0x210 really_probe+0x285/0xc30

To fix this, moving up the assignment of rbnode->block to immediately after the reallocation has succeeded so that the data structure stays valid even if the second reallocation fails.

Reported-by: Hulk Robot hulkci@huawei.com Fixes: 3f4ff561bc88b ("regmap: rbtree: Make cache_present bitmap per node") Signed-off-by: Yang Yingliang yangyingliang@huawei.com Link: https://lore.kernel.org/r/20211012023735.1632786-1-yangyingliang@huawei.com Signed-off-by: Mark Brown broonie@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

Conflicts: drivers/base/regmap/regcache-rbtree.c [Fix context] Signed-off-by: dinglongwei dinglongwei1@huawei.com --- drivers/base/regmap/regcache-rbtree.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c index 09580b1448bc..b6f8f4059e25 100644 --- a/drivers/base/regmap/regcache-rbtree.c +++ b/drivers/base/regmap/regcache-rbtree.c @@ -295,14 +295,14 @@ static int regcache_rbtree_insert_to_block(struct regmap *map, if (!blk) return -ENOMEM;

+ rbnode->block = blk; + if (BITS_TO_LONGS(blklen) > BITS_TO_LONGS(rbnode->blklen)) { present = krealloc(rbnode->cache_present, BITS_TO_LONGS(blklen) * sizeof(*present), map->alloc_flags); - if (!present) { - kfree(blk); + if (!present) return -ENOMEM; - }

memset(present + BITS_TO_LONGS(rbnode->blklen), 0, (BITS_TO_LONGS(blklen) - BITS_TO_LONGS(rbnode->blklen)) @@ -319,7 +319,6 @@ static int regcache_rbtree_insert_to_block(struct regmap *map, }

/* update the rbnode block, its size and the base register */ - rbnode->block = blk; rbnode->blklen = blklen; rbnode->base_reg = base_reg; rbnode->cache_present = present;