From: Rick Edgecombe <rick.p.edgecombe@intel.com>
To: 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>,
Borislav Petkov <bp@alien8.de>, Nadav Amit <nadav.amit@gmail.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Peter Zijlstra <peterz@infradead.org>,
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,
Nadav Amit <namit@vmware.com>,
Rick Edgecombe <rick.p.edgecombe@intel.com>
Subject: [PATCH v3 08/20] x86/ftrace: Set trampoline pages as executable
Date: Thu, 21 Feb 2019 15:44:39 -0800 [thread overview]
Message-ID: <20190221234451.17632-9-rick.p.edgecombe@intel.com> (raw)
In-Reply-To: <20190221234451.17632-1-rick.p.edgecombe@intel.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 8257a59704ae..13c8249b197f 100644
--- a/arch/x86/kernel/ftrace.c
+++ b/arch/x86/kernel/ftrace.c
@@ -742,6 +742,7 @@ 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;
@@ -774,6 +775,7 @@ 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);
@@ -818,6 +820,12 @@ 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:[~2019-02-21 23:52 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-02-21 23:44 [PATCH v3 00/20] Merge text_poke fixes and executable lockdowns Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 01/20] x86/jump_label: Use text_poke_early() during early init Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 02/20] x86/mm: Introduce temporary mm structs Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 03/20] x86/mm: Save DRs when loading a temporary mm Rick Edgecombe
2019-02-22 0:07 ` Sean Christopherson
2019-02-22 0:17 ` Nadav Amit
2019-02-21 23:44 ` [PATCH v3 04/20] fork: Provide a function for copying init_mm Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 05/20] x86/alternative: Initialize temporary mm for patching Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 06/20] x86/alternative: Use temporary mm for text poking Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 07/20] x86/kgdb: Avoid redundant comparison of patched code Rick Edgecombe
2019-02-21 23:44 ` Rick Edgecombe [this message]
2019-02-21 23:44 ` [PATCH v3 09/20] x86/kprobes: Set instruction page as executable Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 10/20] x86/module: Avoid breaking W^X while loading modules Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 11/20] x86/jump-label: Remove support for custom poker Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 12/20] x86/alternative: Remove the return value of text_poke_*() Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 13/20] x86/mm/cpa: Add set_direct_map_ functions Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 14/20] mm: Make hibernate handle unmapped pages Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 15/20] vmalloc: Add flag for free of special permsissions Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 16/20] modules: Use vmalloc special flag Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 17/20] bpf: " Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 18/20] x86/ftrace: " Rick Edgecombe
2019-02-22 0:22 ` Steven Rostedt
2019-02-22 0:55 ` Edgecombe, Rick P
2019-02-21 23:44 ` [PATCH v3 19/20] x86/kprobes: " Rick Edgecombe
2019-02-21 23:44 ` [PATCH v3 20/20] x86/alternative: Comment about module removal races Rick Edgecombe
2019-02-22 16:14 ` [PATCH v3 00/20] Merge text_poke fixes and executable lockdowns Borislav Petkov
2019-02-22 18:32 ` Edgecombe, Rick P
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