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From: "Christopher M. Riedl" <cmr@informatik.wtf>
To: linuxppc-dev@lists.ozlabs.org, kernel-hardening@lists.openwall.com
Subject: [PATCH 4/5] powerpc/lib: Add LKDTM accessor for patching addr
Date: Wed,  3 Jun 2020 00:19:11 -0500	[thread overview]
Message-ID: <20200603051912.23296-5-cmr@informatik.wtf> (raw)
In-Reply-To: <20200603051912.23296-1-cmr@informatik.wtf>

When live patching a STRICT_RWX kernel, a mapping is installed at a
"patching address" with temporary write permissions. Provide a
LKDTM-only accessor function for this address in preparation for a LKDTM
test which attempts to "hijack" this mapping by writing to it from
another CPU.

Signed-off-by: Christopher M. Riedl <cmr@informatik.wtf>
---
 arch/powerpc/lib/code-patching.c | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index df0765845204..c23453049116 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -52,6 +52,13 @@ int raw_patch_instruction(struct ppc_inst *addr, struct ppc_inst instr)
 static struct mm_struct *patching_mm __ro_after_init;
 static unsigned long patching_addr __ro_after_init;
 
+#ifdef CONFIG_LKDTM
+unsigned long read_cpu_patching_addr(unsigned int cpu)
+{
+	return patching_addr;
+}
+#endif
+
 void __init poking_init(void)
 {
 	spinlock_t *ptl; /* for protecting pte table */
-- 
2.26.2


  parent reply	other threads:[~2020-06-03  5:18 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-03  5:19 [PATCH 0/5] Use per-CPU temporary mappings for patching Christopher M. Riedl
2020-06-03  5:19 ` [PATCH 1/5] powerpc/mm: Introduce temporary mm Christopher M. Riedl
2020-06-03  6:58   ` Christophe Leroy
2020-06-11  3:34     ` Christopher M. Riedl
2020-06-03  5:19 ` [PATCH 2/5] powerpc/lib: Initialize a temporary mm for code patching Christopher M. Riedl
2020-06-03  7:01   ` Christophe Leroy
2020-06-11  3:29     ` Christopher M. Riedl
2020-06-03  5:19 ` [PATCH 3/5] powerpc/lib: Use " Christopher M. Riedl
2020-06-03  7:12   ` Christophe Leroy
2020-06-11  3:31     ` Christopher M. Riedl
2020-06-03  5:19 ` Christopher M. Riedl [this message]
2020-06-03  7:14   ` [PATCH 4/5] powerpc/lib: Add LKDTM accessor for patching addr Christophe Leroy
2020-06-09  4:40     ` Christopher M. Riedl
2020-06-03  5:19 ` [PATCH 5/5] powerpc: Add LKDTM test to hijack a patch mapping Christopher M. Riedl
2020-06-03  7:20   ` Christophe Leroy
2020-06-09  4:48     ` Christopher M. Riedl
2020-06-15  6:37   ` Christophe Leroy

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