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From: "Christopher M. Riedl" <cmr@linux.ibm.com>
To: linuxppc-dev@lists.ozlabs.org
Cc: tglx@linutronix.de, x86@kernel.org,
	linux-hardening@vger.kernel.org, keescook@chromium.org,
	npiggin@gmail.com, dja@axtens.net, peterz@infradead.org
Subject: [PATCH v5 8/8] lkdtm/powerpc: Fix code patching hijack test
Date: Tue, 13 Jul 2021 00:31:13 -0500	[thread overview]
Message-ID: <20210713053113.4632-9-cmr@linux.ibm.com> (raw)
In-Reply-To: <20210713053113.4632-1-cmr@linux.ibm.com>

Code patching on powerpc with a STRICT_KERNEL_RWX uses a userspace
address in a temporary mm on Radix now. Use __put_user() to avoid write
failures due to KUAP when attempting a "hijack" on the patching address.
__put_user() also works with the non-userspace, vmalloc-based patching
address on non-Radix MMUs.

Signed-off-by: Christopher M. Riedl <cmr@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 41e87e5f9cc86..da6a34a0a49fb 100644
--- a/drivers/misc/lkdtm/perms.c
+++ b/drivers/misc/lkdtm/perms.c
@@ -262,16 +262,7 @@ 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;
-
-err:
-	return false;
-#endif
-#ifdef CONFIG_X86_64
 	return !__put_user(data, addr);
-#endif
 }
 
 static int lkdtm_patching_cpu(void *data)
-- 
2.26.1


  parent reply	other threads:[~2021-07-13  5:31 UTC|newest]

Thread overview: 24+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-07-13  5:31 [PATCH v5 0/8] Use per-CPU temporary mappings for patching on Radix MMU Christopher M. Riedl
2021-07-13  5:31 ` [PATCH v5 1/8] powerpc: Add LKDTM accessor for patching addr Christopher M. Riedl
2021-07-13  5:31 ` [PATCH v5 2/8] lkdtm/powerpc: Add test to hijack a patch mapping Christopher M. Riedl
2021-08-05  9:13   ` Christophe Leroy
2021-08-11 17:57     ` Christopher M. Riedl
2021-08-11 18:07       ` Kees Cook
2021-07-13  5:31 ` [PATCH v5 3/8] x86_64: Add LKDTM accessor for patching addr Christopher M. Riedl
2021-07-13  5:31 ` [PATCH v5 4/8] lkdtm/x86_64: Add test to hijack a patch mapping Christopher M. Riedl
2021-08-05  9:09   ` Christophe Leroy
2021-08-11 17:53     ` Christopher M. Riedl
2021-07-13  5:31 ` [PATCH v5 5/8] powerpc/64s: Introduce temporary mm for Radix MMU Christopher M. Riedl
2021-08-05  9:27   ` Christophe Leroy
2021-08-11 18:02     ` Christopher M. Riedl
2021-07-13  5:31 ` [PATCH v5 6/8] powerpc: Rework and improve STRICT_KERNEL_RWX patching Christopher M. Riedl
2021-08-05  9:34   ` Christophe Leroy
2021-08-11 18:10     ` Christopher M. Riedl
2021-07-13  5:31 ` [PATCH v5 7/8] powerpc/64s: Initialize and use a temporary mm for patching on Radix Christopher M. Riedl
2021-08-05  9:48   ` Christophe Leroy
2021-08-11 18:28     ` Christopher M. Riedl
2021-07-13  5:31 ` Christopher M. Riedl [this message]
2021-08-05  9:18   ` [PATCH v5 8/8] lkdtm/powerpc: Fix code patching hijack test Christophe Leroy
2021-08-11 17:57     ` Christopher M. Riedl
2021-08-05  9:03 ` [PATCH v5 0/8] Use per-CPU temporary mappings for patching on Radix MMU Christophe Leroy
2021-08-11 17:49   ` Christopher M. Riedl

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