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
Subject: [RESEND PATCH v4 03/11] x86_64: Add LKDTM accessor for patching addr
Date: Wed, 5 May 2021 23:34:44 -0500 [thread overview]
Message-ID: <20210506043452.9674-4-cmr@linux.ibm.com> (raw)
In-Reply-To: <20210506043452.9674-1-cmr@linux.ibm.com>
When live patching with STRICT_KERNEL_RWX 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@linux.ibm.com>
---
arch/x86/include/asm/text-patching.h | 4 ++++
arch/x86/kernel/alternative.c | 7 +++++++
2 files changed, 11 insertions(+)
diff --git a/arch/x86/include/asm/text-patching.h b/arch/x86/include/asm/text-patching.h
index b7421780e4e92..f0caf9ee13bd8 100644
--- a/arch/x86/include/asm/text-patching.h
+++ b/arch/x86/include/asm/text-patching.h
@@ -167,4 +167,8 @@ void int3_emulate_ret(struct pt_regs *regs)
}
#endif /* !CONFIG_UML_X86 */
+#if IS_BUILTIN(CONFIG_LKDTM)
+unsigned long read_cpu_patching_addr(unsigned int cpu);
+#endif
+
#endif /* _ASM_X86_TEXT_PATCHING_H */
diff --git a/arch/x86/kernel/alternative.c b/arch/x86/kernel/alternative.c
index 8d778e46725d2..4c95fdd9b1965 100644
--- a/arch/x86/kernel/alternative.c
+++ b/arch/x86/kernel/alternative.c
@@ -852,6 +852,13 @@ static inline void unuse_temporary_mm(temp_mm_state_t prev_state)
__ro_after_init struct mm_struct *poking_mm;
__ro_after_init unsigned long poking_addr;
+#if IS_BUILTIN(CONFIG_LKDTM)
+unsigned long read_cpu_patching_addr(unsigned int cpu)
+{
+ return poking_addr;
+}
+#endif
+
static void *__text_poke(void *addr, const void *opcode, size_t len)
{
bool cross_page_boundary = offset_in_page(addr) + len > PAGE_SIZE;
--
2.26.1
next prev parent reply other threads:[~2021-05-06 4:35 UTC|newest]
Thread overview: 30+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-06 4:34 [RESEND PATCH v4 00/11] Use per-CPU temporary mappings for patching Christopher M. Riedl
2021-05-06 4:34 ` [RESEND PATCH v4 01/11] powerpc: Add LKDTM accessor for patching addr Christopher M. Riedl
2021-05-06 4:34 ` [RESEND PATCH v4 02/11] lkdtm/powerpc: Add test to hijack a patch mapping Christopher M. Riedl
2021-05-06 4:34 ` Christopher M. Riedl [this message]
2021-05-06 4:34 ` [RESEND PATCH v4 04/11] lkdtm/x86_64: " Christopher M. Riedl
2021-05-06 4:34 ` [RESEND PATCH v4 05/11] powerpc/64s: Add ability to skip SLB preload Christopher M. Riedl
2021-06-21 3:13 ` Daniel Axtens
2021-07-01 3:48 ` Christopher M. Riedl
2021-07-01 4:15 ` Nicholas Piggin
2021-07-01 5:28 ` Christopher M. Riedl
2021-07-01 6:04 ` Nicholas Piggin
2021-07-01 6:53 ` Christopher M. Riedl
2021-07-01 7:37 ` Nicholas Piggin
2021-07-01 11:30 ` Nicholas Piggin
2021-07-09 4:55 ` Christopher M. Riedl
2021-05-06 4:34 ` [RESEND PATCH v4 06/11] powerpc: Introduce temporary mm Christopher M. Riedl
2021-05-06 4:34 ` [RESEND PATCH v4 07/11] powerpc/64s: Make slb_allocate_user() non-static Christopher M. Riedl
2021-05-06 4:34 ` [RESEND PATCH v4 08/11] powerpc: Initialize and use a temporary mm for patching Christopher M. Riedl
2021-06-21 3:19 ` Daniel Axtens
2021-07-01 5:11 ` Christopher M. Riedl
2021-07-01 6:12 ` Nicholas Piggin
2021-07-01 7:02 ` Christopher M. Riedl
2021-07-01 7:51 ` Nicholas Piggin
2021-07-09 5:03 ` Christopher M. Riedl
2021-05-06 4:34 ` [RESEND PATCH v4 09/11] lkdtm/powerpc: Fix code patching hijack test Christopher M. Riedl
2021-05-06 4:34 ` [RESEND PATCH v4 10/11] powerpc: Protect patching_mm with a lock Christopher M. Riedl
2021-05-06 10:51 ` Peter Zijlstra
2021-05-07 20:03 ` Christopher M. Riedl
2021-05-07 22:26 ` Peter Zijlstra
2021-05-06 4:34 ` [RESEND PATCH v4 11/11] powerpc: Use patch_instruction_unlocked() in loops Christopher M. Riedl
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