2022-03-09 01:42:46

by andrey.konovalov

[permalink] [raw]
Subject: [PATCH mm] fix for "kasan, vmalloc: only tag normal vmalloc allocations"

From: Andrey Konovalov <[email protected]>

"kasan, vmalloc: only tag normal vmalloc allocations" unintentionally
disabled poisoning of executable memory for the Generic mode. Fix it.

Reported-by: Vasily Gorbik <[email protected]>
Signed-off-by: Andrey Konovalov <[email protected]>
---
mm/kasan/shadow.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/mm/kasan/shadow.c b/mm/kasan/shadow.c
index 7272e248db87..a4f07de21771 100644
--- a/mm/kasan/shadow.c
+++ b/mm/kasan/shadow.c
@@ -489,10 +489,11 @@ void *__kasan_unpoison_vmalloc(const void *start, unsigned long size,
return (void *)start;

/*
- * Don't tag executable memory.
+ * Don't tag executable memory with the tag-based mode.
* The kernel doesn't tolerate having the PC register tagged.
*/
- if (!(flags & KASAN_VMALLOC_PROT_NORMAL))
+ if (IS_ENABLED(CONFIG_KASAN_SW_TAGS) &&
+ !(flags & KASAN_VMALLOC_PROT_NORMAL))
return (void *)start;

start = set_tag(start, kasan_random_tag());
--
2.25.1