From: nadav.amit@gmail.com
To: Peter Zijlstra <peterz@infradead.org>,
Borislav Petkov <bp@alien8.de>, Andy Lutomirski <luto@kernel.org>,
Ingo Molnar <mingo@redhat.com>
Cc: linux-kernel@vger.kernel.org, x86@kernel.org, hpa@zytor.com,
Thomas Gleixner <tglx@linutronix.de>,
Nadav Amit <nadav.amit@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
linux_dti@icloud.com, linux-integrity@vger.kernel.org,
linux-security-module@vger.kernel.org, akpm@linux-foundation.org,
kernel-hardening@lists.openwall.com, linux-mm@kvack.org,
will.deacon@arm.com, ard.biesheuvel@linaro.org,
kristen@linux.intel.com, deneen.t.dock@intel.com,
Rick Edgecombe <rick.p.edgecombe@intel.com>,
Nadav Amit <namit@vmware.com>
Subject: [PATCH v6 10/24] x86/ftrace: Set trampoline pages as executable
Date: Fri, 26 Apr 2019 16:22:49 -0700 [thread overview]
Message-ID: <20190426232303.28381-11-nadav.amit@gmail.com> (raw)
In-Reply-To: <20190426232303.28381-1-nadav.amit@gmail.com>
From: Nadav Amit <namit@vmware.com>
Since alloc_module() will not set the pages as executable soon, set
ftrace trampoline pages as executable after they are allocated.
For the time being, do not change ftrace to use the text_poke()
interface. As a result, ftrace still breaks W^X.
Reviewed-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Signed-off-by: Nadav Amit <namit@vmware.com>
Signed-off-by: Rick Edgecombe <rick.p.edgecombe@intel.com>
---
arch/x86/kernel/ftrace.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/arch/x86/kernel/ftrace.c b/arch/x86/kernel/ftrace.c
index ef49517f6bb2..53ba1aa3a01f 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -730,6 +730,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
unsigned long end_offset;
unsigned long op_offset;
unsigned long offset;
+ unsigned long npages;
unsigned long size;
unsigned long retq;
unsigned long *ptr;
@@ -762,6 +763,7 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
return 0;
*tramp_size = size + RET_SIZE + sizeof(void *);
+ npages = DIV_ROUND_UP(*tramp_size, PAGE_SIZE);
/* Copy ftrace_caller onto the trampoline memory */
ret = probe_kernel_read(trampoline, (void *)start_offset, size);
@@ -806,6 +808,12 @@ create_trampoline(struct ftrace_ops *ops, unsigned int *tramp_size)
/* ALLOC_TRAMP flags lets us know we created it */
ops->flags |= FTRACE_OPS_FL_ALLOC_TRAMP;
+ /*
+ * Module allocation needs to be completed by making the page
+ * executable. The page is still writable, which is a security hazard,
+ * but anyhow ftrace breaks W^X completely.
+ */
+ set_memory_x((unsigned long)trampoline, npages);
return (unsigned long)trampoline;
fail:
tramp_free(trampoline, *tramp_size);
--
2.17.1
next prev parent reply other threads:[~2019-04-26 23:22 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-26 23:22 [PATCH v6 00/24] x86: text_poke() fixes and executable lockdowns nadav.amit
2019-04-26 23:22 ` [PATCH v6 01/24] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" nadav.amit
2019-04-26 23:22 ` [PATCH v6 02/24] x86/jump_label: Use text_poke_early() during early init nadav.amit
2019-04-26 23:22 ` [PATCH v6 03/24] x86/mm: Introduce temporary mm structs nadav.amit
2019-04-26 23:22 ` [PATCH v6 04/24] x86/mm: Save debug registers when loading a temporary mm nadav.amit
2019-04-26 23:22 ` [PATCH v6 05/24] uprobes: Initialize uprobes earlier nadav.amit
2019-04-26 23:22 ` [PATCH v6 06/24] fork: Provide a function for copying init_mm nadav.amit
2019-04-26 23:22 ` [PATCH v6 07/24] x86/alternative: Initialize temporary mm for patching nadav.amit
2019-04-26 23:22 ` [PATCH v6 08/24] x86/alternative: Use temporary mm for text poking nadav.amit
2019-04-26 23:22 ` [PATCH v6 09/24] x86/kgdb: Avoid redundant comparison of patched code nadav.amit
2019-04-26 23:22 ` nadav.amit [this message]
2019-04-26 23:22 ` [PATCH v6 11/24] x86/kprobes: Set instruction page as executable nadav.amit
2019-04-26 23:22 ` [PATCH v6 12/24] x86/module: Avoid breaking W^X while loading modules nadav.amit
2019-04-26 23:22 ` [PATCH v6 13/24] x86/jump-label: Remove support for custom poker nadav.amit
2019-04-26 23:22 ` [PATCH v6 14/24] x86/alternative: Remove the return value of text_poke_*() nadav.amit
2019-04-26 23:22 ` [PATCH v6 15/24] x86/mm/cpa: Add set_direct_map_ functions nadav.amit
2019-04-26 23:22 ` [PATCH v6 16/24] mm: Make hibernate handle unmapped pages nadav.amit
2019-04-26 23:22 ` [PATCH v6 17/24] vmalloc: Add flag for free of special permsissions nadav.amit
2019-04-26 23:22 ` [PATCH v6 18/24] modules: Use vmalloc special flag nadav.amit
2019-04-26 23:22 ` [PATCH v6 19/24] bpf: " nadav.amit
2019-04-26 23:22 ` [PATCH v6 20/24] x86/ftrace: " nadav.amit
2019-04-26 23:23 ` [PATCH v6 21/24] x86/kprobes: " nadav.amit
2019-04-26 23:23 ` [PATCH v6 22/24] x86/alternative: Comment about module removal races nadav.amit
2019-04-26 23:23 ` [PATCH v6 23/24] mm/tlb: Provide default nmi_uaccess_okay() nadav.amit
2019-04-26 23:23 ` [PATCH v6 24/24] bpf: Fail bpf_probe_write_user() while mm is switched nadav.amit
2019-04-27 10:22 ` [PATCH v6 00/24] x86: text_poke() fixes and executable lockdowns Ingo Molnar
2019-04-27 10:32 ` Peter Zijlstra
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