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[v2,8/8] kasan: test: avoid corrupting memory in kasan_rcu_uaf

Message ID b6f2c3bf712d2457c783fa59498225b66a634f62.1628779805.git.andreyknvl@gmail.com (mailing list archive)
State New
Headers show
Series kasan: test: avoid crashing the kernel with HW_TAGS | expand

Commit Message

andrey.konovalov@linux.dev Aug. 12, 2021, 3:05 p.m. UTC 
From: Andrey Konovalov <andreyknvl@gmail.com>

kasan_rcu_uaf() writes to freed memory via kasan_rcu_reclaim(), which is
only safe with the GENERIC mode (as it uses quarantine). For other modes,
this test corrupts kernel memory, which might result in a crash.

Turn the write into a read.

Signed-off-by: Andrey Konovalov <andreyknvl@gmail.com>
---
 lib/test_kasan_module.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
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Patch

diff --git a/lib/test_kasan_module.c b/lib/test_kasan_module.c
index fa73b9df0be4..7ebf433edef3 100644
--- a/lib/test_kasan_module.c
+++ b/lib/test_kasan_module.c
@@ -71,7 +71,7 @@  static noinline void __init kasan_rcu_reclaim(struct rcu_head *rp)
 						struct kasan_rcu_info, rcu);
 
 	kfree(fp);
-	fp->i = 1;
+	((volatile struct kasan_rcu_info *)fp)->i;
 }
 
 static noinline void __init kasan_rcu_uaf(void)