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authorYang Yingliang <yangyingliang@huawei.com>2021-10-12 04:37:35 +0200
committerMark Brown <broonie@kernel.org>2021-10-12 12:48:43 +0200
commit55e6d8037805b3400096d621091dfbf713f97e83 (patch)
tree75c0e1a9f46cbdc4a92bb43ef7a5adaa76f19feb /drivers/base/regmap/regcache-rbtree.c
parentMerge series "Use raw spinlocks in the ls-extirq driver" from Vladimir Oltean... (diff)
downloadlinux-55e6d8037805b3400096d621091dfbf713f97e83.tar.xz
linux-55e6d8037805b3400096d621091dfbf713f97e83.zip
regmap: Fix possible double-free in regcache_rbtree_exit()
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>
Diffstat (limited to 'drivers/base/regmap/regcache-rbtree.c')
-rw-r--r--drivers/base/regmap/regcache-rbtree.c7
1 files changed, 3 insertions, 4 deletions
diff --git a/drivers/base/regmap/regcache-rbtree.c b/drivers/base/regmap/regcache-rbtree.c
index cfa29dc89bbf..fabf87058d80 100644
--- a/drivers/base/regmap/regcache-rbtree.c
+++ b/drivers/base/regmap/regcache-rbtree.c
@@ -281,14 +281,14 @@ 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),
GFP_KERNEL);
- 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))
@@ -305,7 +305,6 @@ 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;