From: "Christopher M. Riedl" <cmr@codefail.de>
To: linuxppc-dev@lists.ozlabs.org
Cc: kernel-hardening@lists.openwall.com
Subject: [PATCH v3 1/6] powerpc: Add LKDTM accessor for patching addr
Date: Thu, 27 Aug 2020 00:26:54 -0500 [thread overview]
Message-ID: <20200827052659.24922-2-cmr@codefail.de> (raw)
In-Reply-To: <20200827052659.24922-1-cmr@codefail.de>
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@codefail.de>
---
arch/powerpc/include/asm/code-patching.h | 4 ++++
arch/powerpc/lib/code-patching.c | 7 +++++++
2 files changed, 11 insertions(+)
diff --git a/arch/powerpc/include/asm/code-patching.h b/arch/powerpc/include/asm/code-patching.h
index eacc9102c251..7216d6a6bb0a 100644
--- a/arch/powerpc/include/asm/code-patching.h
+++ b/arch/powerpc/include/asm/code-patching.h
@@ -187,4 +187,8 @@ static inline unsigned long ppc_kallsyms_lookup_name(const char *name)
___PPC_RA(__REG_R1) | PPC_LR_STKOFF)
#endif /* CONFIG_PPC64 */
+#if defined(CONFIG_LKDTM) && defined(CONFIG_STRICT_KERNEL_RWX)
+unsigned long read_cpu_patching_addr(unsigned int cpu);
+#endif
+
#endif /* _ASM_POWERPC_CODE_PATCHING_H */
diff --git a/arch/powerpc/lib/code-patching.c b/arch/powerpc/lib/code-patching.c
index 8c3934ea6220..85d3fdca9452 100644
--- a/arch/powerpc/lib/code-patching.c
+++ b/arch/powerpc/lib/code-patching.c
@@ -46,6 +46,13 @@ int raw_patch_instruction(struct ppc_inst *addr, struct ppc_inst instr)
#ifdef CONFIG_STRICT_KERNEL_RWX
static DEFINE_PER_CPU(struct vm_struct *, text_poke_area);
+#ifdef CONFIG_LKDTM
+unsigned long read_cpu_patching_addr(unsigned int cpu)
+{
+ return (unsigned long)(per_cpu(text_poke_area, cpu))->addr;
+}
+#endif
+
static int text_area_cpu_up(unsigned int cpu)
{
struct vm_struct *area;
--
2.28.0
next prev parent reply other threads:[~2020-08-27 5:25 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-08-27 5:26 [PATCH v3 0/6] Use per-CPU temporary mappings for patching Christopher M. Riedl
2020-08-27 5:26 ` Christopher M. Riedl [this message]
2020-08-27 5:26 ` [PATCH v3 2/6] x86: Add LKDTM accessor for patching addr Christopher M. Riedl
2020-08-27 5:26 ` [PATCH v3 3/6] Add LKDTM test to hijack a patch mapping (powerpc,x86_64) Christopher M. Riedl
2020-08-27 10:11 ` [PATCH v3 3/6] Add LKDTM test to hijack a patch mapping (powerpc, x86_64) kernel test robot
2020-08-27 18:10 ` kernel test robot
2020-08-27 5:26 ` [PATCH v3 4/6] powerpc: Introduce temporary mm Christopher M. Riedl
2020-08-27 14:15 ` Jann Horn
2020-09-07 0:15 ` Christopher M. Riedl
2020-08-27 5:26 ` [PATCH v3 5/6] powerpc: Initialize a temporary mm for code patching Christopher M. Riedl
2020-08-27 5:26 ` [PATCH v3 6/6] powerpc: Use " Christopher M. Riedl
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