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>, Steven Rostedt <rostedt@goodmis.org>, Rick Edgecombe <rick.p.edgecombe@intel.com> Subject: [PATCH v2 08/20] x86/ftrace: set trampoline pages as executable Date: Mon, 28 Jan 2019 16:34:10 -0800 Message-ID: <20190129003422.9328-9-rick.p.edgecombe@intel.com> (raw) In-Reply-To: <20190129003422.9328-1-rick.p.edgecombe@intel.com> From: Nadav Amit <namit@vmware.com> Since alloc_module() will not set the pages as executable soon, we need to do so for ftrace trampoline pages after they are allocated. For the time being, we do not change ftrace to use the text_poke() interface. As a result, ftrace breaks still breaks W^X. Cc: Steven Rostedt <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 index Thread overview: 71+ messages / expand[flat|nested] mbox.gz Atom feed top 2019-01-29 0:34 [PATCH v2 00/20] Merge text_poke fixes and executable lockdowns Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 01/20] Fix "x86/alternatives: Lockdep-enforce text_mutex in text_poke*()" Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 02/20] x86/jump_label: Use text_poke_early() during early init Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 03/20] x86/mm: temporary mm struct Rick Edgecombe 2019-01-31 11:29 ` Borislav Petkov 2019-01-31 22:19 ` Nadav Amit 2019-02-01 0:08 ` Borislav Petkov 2019-02-01 0:25 ` Nadav Amit 2019-02-04 14:28 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 04/20] fork: provide a function for copying init_mm Rick Edgecombe 2019-02-05 8:53 ` Borislav Petkov 2019-02-05 9:03 ` Nadav Amit 2019-01-29 0:34 ` [PATCH v2 05/20] x86/alternative: initializing temporary mm for patching Rick Edgecombe 2019-02-05 9:18 ` Borislav Petkov 2019-02-11 0:39 ` Nadav Amit 2019-02-11 5:18 ` Andy Lutomirski 2019-02-11 18:04 ` Nadav Amit 2019-02-11 19:07 ` Andy Lutomirski 2019-02-11 19:18 ` Nadav Amit 2019-02-11 22:47 ` Andy Lutomirski 2019-02-12 18:23 ` Nadav Amit 2019-01-29 0:34 ` [PATCH v2 06/20] x86/alternative: use temporary mm for text poking Rick Edgecombe 2019-02-05 9:58 ` Borislav Petkov 2019-02-05 11:31 ` Peter Zijlstra 2019-02-05 12:35 ` Borislav Petkov 2019-02-05 13:25 ` Peter Zijlstra 2019-02-05 17:54 ` Nadav Amit 2019-02-05 13:29 ` Peter Zijlstra 2019-01-29 0:34 ` [PATCH v2 07/20] x86/kgdb: avoid redundant comparison of patched code Rick Edgecombe 2019-01-29 0:34 ` Rick Edgecombe [this message] 2019-01-29 0:34 ` [PATCH v2 09/20] x86/kprobes: instruction pages initialization enhancements Rick Edgecombe 2019-02-11 18:22 ` Borislav Petkov 2019-02-11 19:36 ` Nadav Amit 2019-01-29 0:34 ` [PATCH v2 10/20] x86: avoid W^X being broken during modules loading Rick Edgecombe 2019-02-11 18:29 ` Borislav Petkov 2019-02-11 18:45 ` Nadav Amit 2019-02-11 19:01 ` Borislav Petkov 2019-02-11 19:09 ` Nadav Amit 2019-02-11 19:10 ` Borislav Petkov 2019-02-11 19:27 ` Nadav Amit 2019-02-11 19:42 ` Borislav Petkov 2019-02-11 20:32 ` Nadav Amit 2019-03-07 15:10 ` [PATCH] x86/cpufeature: Remove __pure attribute to _static_cpu_has() Borislav Petkov 2019-03-07 16:43 ` hpa 2019-03-07 17:02 ` Borislav Petkov 2019-03-07 7:29 ` [PATCH v2 10/20] x86: avoid W^X being broken during modules loading Borislav Petkov 2019-03-07 16:53 ` hpa 2019-03-07 17:06 ` Borislav Petkov 2019-03-07 20:02 ` Andy Lutomirski 2019-03-07 20:25 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 11/20] x86/jump-label: remove support for custom poker Rick Edgecombe 2019-02-11 18:37 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 12/20] x86/alternative: Remove the return value of text_poke_*() Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 13/20] Add set_alias_ function and x86 implementation Rick Edgecombe 2019-02-11 19:09 ` Borislav Petkov 2019-02-11 19:27 ` Edgecombe, Rick P 2019-02-11 22:59 ` Andy Lutomirski 2019-02-12 0:01 ` Edgecombe, Rick P 2019-01-29 0:34 ` [PATCH v2 14/20] mm: Make hibernate handle unmapped pages Rick Edgecombe 2019-02-19 11:04 ` Borislav Petkov 2019-02-19 21:28 ` Edgecombe, Rick P 2019-02-20 16:07 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 15/20] vmalloc: New flags for safe vfree on special perms Rick Edgecombe 2019-02-19 12:48 ` Borislav Petkov 2019-02-19 19:42 ` Edgecombe, Rick P 2019-02-20 16:14 ` Borislav Petkov 2019-01-29 0:34 ` [PATCH v2 16/20] modules: Use vmalloc special flag Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 17/20] bpf: " Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 18/20] x86/ftrace: " Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 19/20] x86/kprobes: " Rick Edgecombe 2019-01-29 0:34 ` [PATCH v2 20/20] x86/alternative: comment about module removal races Rick Edgecombe
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