From: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
To: Ingo Molnar <mingo@redhat.com>,
Thomas Gleixner <tglx@linutronix.de>,
"H. Peter Anvin" <hpa@zytor.com>,
Andy Lutomirski <luto@kernel.org>, Borislav Petkov <bp@suse.de>
Cc: Peter Zijlstra <peterz@infradead.org>,
Andrew Morton <akpm@linux-foundation.org>,
Brian Gerst <brgerst@gmail.com>,
Chris Metcalf <cmetcalf@mellanox.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Paolo Bonzini <pbonzini@redhat.com>,
Liang Z Li <liang.z.li@intel.com>,
Masami Hiramatsu <mhiramat@kernel.org>,
Huang Rui <ray.huang@amd.com>, Jiri Slaby <jslaby@suse.cz>,
Jonathan Corbet <corbet@lwn.net>,
"Michael S. Tsirkin" <mst@redhat.com>,
Paul Gortmaker <paul.gortmaker@windriver.com>,
Vlastimil Babka <vbabka@suse.cz>, Chen Yucong <slaoub@gmail.com>,
"Ravi V. Shankar" <ravi.v.shankar@intel.com>,
Shuah Khan <shuah@kernel.org>,
linux-kernel@vger.kernel.org, x86@kernel.org,
ricardo.neri@intel.com,
Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
Adam Buchbinder <adam.buchbinder@gmail.com>,
Colin Ian King <colin.king@canonical.com>,
Lorenzo Stoakes <lstoakes@gmail.com>,
Qiaowei Ren <qiaowei.ren@intel.com>,
Arnaldo Carvalho de Melo <acme@redhat.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Kees Cook <keescook@chromium.org>,
Thomas Garnier <thgarnie@google.com>,
Dmitry Vyukov <dvyukov@google.com>
Subject: [PATCH v8 20/28] x86/insn-eval: Handle 32-bit address encodings in virtual-8086 mode
Date: Fri, 18 Aug 2017 17:28:01 -0700 [thread overview]
Message-ID: <20170819002809.111312-21-ricardo.neri-calderon@linux.intel.com> (raw)
In-Reply-To: <20170819002809.111312-1-ricardo.neri-calderon@linux.intel.com>
It is possible to utilize 32-bit address encodings in virtual-8086 mode via
an address override instruction prefix. However, the range of the
effective address is still limited to [0x-0xffff]. In such a case, return
error.
Also, linear addresses in virtual-8086 mode are limited to 20 bits. Enforce
such limit by truncating the most significant bytes of the computed linear
address.
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Adam Buchbinder <adam.buchbinder@gmail.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Lorenzo Stoakes <lstoakes@gmail.com>
Cc: Qiaowei Ren <qiaowei.ren@intel.com>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@suse.de>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Ravi V. Shankar <ravi.v.shankar@intel.com>
Cc: x86@kernel.org
Signed-off-by: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
---
arch/x86/lib/insn-eval.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 6537b613d0b3..93a6d1f57c2d 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -801,12 +801,23 @@ static void __user *get_addr_ref_32(struct insn *insn, struct pt_regs *regs)
goto out_err;
/*
+ * Even though 32-bit address encodings are allowed in virtual-8086
+ * mode, the address range is still limited to [0x-0xffff].
+ */
+ if (v8086_mode(regs) && (eff_addr & ~0xffff))
+ goto out_err;
+
+ /*
* Data type long could be 64 bits in size. Ensure that our 32-bit
* effective address is not sign-extended when computing the linear
* address.
*/
linear_addr = (unsigned long)(eff_addr & 0xffffffff) + seg_base_addr;
+ /* Limit linear address to 20 bits */
+ if (v8086_mode(regs))
+ linear_addr &= 0xfffff;
+
return (void __user *)linear_addr;
out_err:
return (void __user *)-1L;
--
2.13.0
next prev parent reply other threads:[~2017-08-19 0:32 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-08-19 0:27 [PATCH v8 00/28] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 01/28] x86/mm: Relocate page fault error codes to traps.h Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 02/28] x86/boot: Relocate definition of the initial state of CR0 Ricardo Neri
2017-08-25 17:41 ` Borislav Petkov
2017-08-31 4:04 ` Ricardo Neri
2017-08-31 9:51 ` Borislav Petkov
2017-09-02 17:35 ` Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 03/28] ptrace,x86: Make user_64bit_mode() available to 32-bit builds Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 04/28] uprobes/x86: Use existing definitions for segment override prefixes Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 05/28] x86/mpx: Use signed variables to compute effective addresses Ricardo Neri
2017-08-29 16:09 ` Borislav Petkov
2017-08-31 4:19 ` Ricardo Neri
2017-08-31 9:52 ` Borislav Petkov
2017-08-19 0:27 ` [PATCH v8 06/28] x86/mpx: Do not use SIB.index if its value is 100b and ModRM.mod is not 11b Ricardo Neri
2017-08-31 19:38 ` Borislav Petkov
2017-09-02 17:19 ` Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 07/28] x86/mpx: Do not use SIB.base if its value is 101b and ModRM.mod = 0 Ricardo Neri
2017-09-06 15:44 ` Borislav Petkov
2017-08-19 0:27 ` [PATCH v8 08/28] x86/mpx, x86/insn: Relocate insn util functions to a new insn-eval file Ricardo Neri
2017-09-06 15:54 ` Borislav Petkov
2017-09-06 19:27 ` Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 09/28] x86/insn-eval: Do not BUG on invalid register type Ricardo Neri
2017-09-07 17:54 ` Borislav Petkov
2017-09-07 20:27 ` Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 10/28] x86/insn-eval: Add a utility function to get register offsets Ricardo Neri
2017-09-08 13:35 ` Borislav Petkov
2017-09-14 18:30 ` Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 11/28] x86/insn-eval: Add utility function to identify string instructions Ricardo Neri
2017-09-08 13:57 ` Borislav Petkov
2017-09-14 18:30 ` Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 12/28] x86/insn-eval: Add utility functions to get segment selector Ricardo Neri
2017-09-26 10:43 ` Borislav Petkov
2017-09-27 4:21 ` Ricardo Neri
2017-09-27 11:47 ` Borislav Petkov
2017-09-27 22:32 ` Ricardo Neri
2017-09-28 9:36 ` Borislav Petkov
2017-09-29 6:06 ` Ricardo Neri
2017-09-29 11:56 ` Borislav Petkov
2017-10-04 16:47 ` Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 13/28] x86/insn-eval: Add utility function to get segment descriptor Ricardo Neri
2017-09-26 18:05 ` Borislav Petkov
2017-09-27 17:39 ` Neri, Ricardo
2017-08-19 0:27 ` [PATCH v8 14/28] x86/insn-eval: Add utility functions to get segment descriptor base address and limit Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 15/28] x86/insn-eval: Add function to get default params of code segment Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 16/28] x86/insn-eval: Indicate a 32-bit displacement if ModRM.mod is 0 and ModRM.rm is 101b Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 17/28] x86/insn-eval: Incorporate segment base in linear address computation Ricardo Neri
2017-08-19 0:27 ` [PATCH v8 18/28] x86/insn-eval: Add support to resolve 32-bit address encodings Ricardo Neri
2017-08-19 0:28 ` [PATCH v8 19/28] x86/insn-eval: Add wrapper function for 32 and 64-bit addresses Ricardo Neri
2017-08-19 0:28 ` Ricardo Neri [this message]
2017-08-19 0:28 ` [PATCH v8 21/28] x86/insn-eval: Add support to resolve 16-bit addressing encodings Ricardo Neri
2017-08-19 0:28 ` [PATCH v8 22/28] x86/cpufeature: Add User-Mode Instruction Prevention definitions Ricardo Neri
2017-08-19 0:28 ` [PATCH v8 23/28] x86: Add emulation code for UMIP instructions Ricardo Neri
2017-08-19 0:28 ` [PATCH v8 24/28] x86/umip: Force a page fault when unable to copy emulated result to user Ricardo Neri
2017-08-19 0:28 ` [PATCH v8 25/28] x86: Enable User-Mode Instruction Prevention Ricardo Neri
2017-08-19 0:28 ` [PATCH v8 26/28] x86/traps: Fixup general protection faults caused by UMIP Ricardo Neri
2017-08-19 0:28 ` [PATCH v8 27/28] selftests/x86: Add tests for User-Mode Instruction Prevention Ricardo Neri
2017-08-19 0:28 ` [PATCH v8 28/28] selftests/x86: Add tests for instruction str and sldt Ricardo Neri
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