[RESEND PATCH v4 09/11] lkdtm/powerpc: Fix code patching hijack test

Christopher M. Riedl cmr at linux.ibm.com
Thu May 6 14:34:50 AEST 2021

Code patching on powerpc with a STRICT_KERNEL_RWX uses a userspace
address in a temporary mm now. Use __put_user() to avoid write failures
due to KUAP when attempting a "hijack" on the patching address.

Signed-off-by: Christopher M. Riedl <cmr at linux.ibm.com>
 drivers/misc/lkdtm/perms.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/misc/lkdtm/perms.c b/drivers/misc/lkdtm/perms.c
index 55c3bec6d3b72..af9bf285fe326 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -268,16 +268,7 @@ static inline u32 lkdtm_read_patch_site(void)
 /* Returns True if the write succeeds */
 static inline bool lkdtm_try_write(u32 data, u32 *addr)
-#ifdef CONFIG_PPC
-	__put_kernel_nofault(addr, &data, u32, err);
-	return true;
-	return false;
-#ifdef CONFIG_X86_64
 	return !__put_user(data, addr);
 static int lkdtm_patching_cpu(void *data)

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