From: Ben Hutchings <ben@decadent.org.uk>
To: linux-kernel@vger.kernel.org, stable@vger.kernel.org
Cc: akpm@linux-foundation.org, "Thomas Gleixner" <tglx@linutronix.de>,
alan@linux.intel.com, "Dan Williams" <dan.j.williams@intel.com>,
gregkh@linuxfoundation.org, linux-arch@vger.kernel.org,
kernel-hardening@lists.openwall.com,
"Kees Cook" <keescook@chromium.org>,
"Al Viro" <viro@zeniv.linux.org.uk>,
"Andi Kleen" <ak@linux.intel.com>,
"Linus Torvalds" <torvalds@linux-foundation.org>
Subject: [PATCH 3.16 75/76] x86/uaccess: Use __uaccess_begin_nospec() and uaccess_try_nospec
Date: Mon, 12 Mar 2018 03:06:12 +0000 [thread overview]
Message-ID: <lsq.1520823972.968056966@decadent.org.uk> (raw)
In-Reply-To: <lsq.1520823971.5976735@decadent.org.uk>
3.16.56-rc1 review patch. If anyone has any objections, please let me know.
------------------
From: Dan Williams <dan.j.williams@intel.com>
commit 304ec1b050310548db33063e567123fae8fd0301 upstream.
Quoting Linus:
I do think that it would be a good idea to very expressly document
the fact that it's not that the user access itself is unsafe. I do
agree that things like "get_user()" want to be protected, but not
because of any direct bugs or problems with get_user() and friends,
but simply because get_user() is an excellent source of a pointer
that is obviously controlled from a potentially attacking user
space. So it's a prime candidate for then finding _subsequent_
accesses that can then be used to perturb the cache.
__uaccess_begin_nospec() covers __get_user() and copy_from_iter() where the
limit check is far away from the user pointer de-reference. In those cases
a barrier_nospec() prevents speculation with a potential pointer to
privileged memory. uaccess_try_nospec covers get_user_try.
Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Suggested-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arch@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Cc: kernel-hardening@lists.openwall.com
Cc: gregkh@linuxfoundation.org
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: alan@linux.intel.com
Link: https://lkml.kernel.org/r/151727416953.33451.10508284228526170604.stgit@dwillia2-desk3.amr.corp.intel.com
[bwh: Backported to 3.16:
- Convert several more functions to use __uaccess_begin_nospec(), that
are just wrappers in mainline
- There's no 'case 8' in __copy_to_user_inatomic()
- Adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
---
--- a/arch/x86/include/asm/uaccess.h
+++ b/arch/x86/include/asm/uaccess.h
@@ -433,7 +433,7 @@ do { \
({ \
int __gu_err; \
unsigned long __gu_val; \
- __uaccess_begin(); \
+ __uaccess_begin_nospec(); \
__get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT); \
__uaccess_end(); \
(x) = (__force __typeof__(*(ptr)))__gu_val; \
@@ -541,7 +541,7 @@ struct __large_struct { unsigned long bu
* get_user_ex(...);
* } get_user_catch(err)
*/
-#define get_user_try uaccess_try
+#define get_user_try uaccess_try_nospec
#define get_user_catch(err) uaccess_catch(err)
#define get_user_ex(x, ptr) do { \
@@ -576,7 +576,7 @@ extern void __cmpxchg_wrong_size(void)
__typeof__(ptr) __uval = (uval); \
__typeof__(*(ptr)) __old = (old); \
__typeof__(*(ptr)) __new = (new); \
- __uaccess_begin(); \
+ __uaccess_begin_nospec(); \
switch (size) { \
case 1: \
{ \
--- a/arch/x86/include/asm/uaccess_32.h
+++ b/arch/x86/include/asm/uaccess_32.h
@@ -48,19 +48,19 @@ __copy_to_user_inatomic(void __user *to,
switch (n) {
case 1:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__put_user_size(*(u8 *)from, (u8 __user *)to,
1, ret, 1);
__uaccess_end();
return ret;
case 2:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__put_user_size(*(u16 *)from, (u16 __user *)to,
2, ret, 2);
__uaccess_end();
return ret;
case 4:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__put_user_size(*(u32 *)from, (u32 __user *)to,
4, ret, 4);
__uaccess_end();
@@ -104,17 +104,17 @@ __copy_from_user_inatomic(void *to, cons
switch (n) {
case 1:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_size(*(u8 *)to, from, 1, ret, 1);
__uaccess_end();
return ret;
case 2:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_size(*(u16 *)to, from, 2, ret, 2);
__uaccess_end();
return ret;
case 4:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_size(*(u32 *)to, from, 4, ret, 4);
__uaccess_end();
return ret;
@@ -154,17 +154,17 @@ __copy_from_user(void *to, const void __
switch (n) {
case 1:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_size(*(u8 *)to, from, 1, ret, 1);
__uaccess_end();
return ret;
case 2:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_size(*(u16 *)to, from, 2, ret, 2);
__uaccess_end();
return ret;
case 4:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_size(*(u32 *)to, from, 4, ret, 4);
__uaccess_end();
return ret;
@@ -182,17 +182,17 @@ static __always_inline unsigned long __c
switch (n) {
case 1:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_size(*(u8 *)to, from, 1, ret, 1);
__uaccess_end();
return ret;
case 2:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_size(*(u16 *)to, from, 2, ret, 2);
__uaccess_end();
return ret;
case 4:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_size(*(u32 *)to, from, 4, ret, 4);
__uaccess_end();
return ret;
--- a/arch/x86/include/asm/uaccess_64.h
+++ b/arch/x86/include/asm/uaccess_64.h
@@ -57,31 +57,31 @@ int __copy_from_user_nocheck(void *dst,
return copy_user_generic(dst, (__force void *)src, size);
switch (size) {
case 1:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(*(u8 *)dst, (u8 __user *)src,
ret, "b", "b", "=q", 1);
__uaccess_end();
return ret;
case 2:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(*(u16 *)dst, (u16 __user *)src,
ret, "w", "w", "=r", 2);
__uaccess_end();
return ret;
case 4:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(*(u32 *)dst, (u32 __user *)src,
ret, "l", "k", "=r", 4);
__uaccess_end();
return ret;
case 8:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(*(u64 *)dst, (u64 __user *)src,
ret, "q", "", "=r", 8);
__uaccess_end();
return ret;
case 10:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(*(u64 *)dst, (u64 __user *)src,
ret, "q", "", "=r", 10);
if (likely(!ret))
@@ -91,7 +91,7 @@ int __copy_from_user_nocheck(void *dst,
__uaccess_end();
return ret;
case 16:
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(*(u64 *)dst, (u64 __user *)src,
ret, "q", "", "=r", 16);
if (likely(!ret))
@@ -190,7 +190,7 @@ int __copy_in_user(void __user *dst, con
switch (size) {
case 1: {
u8 tmp;
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(tmp, (u8 __user *)src,
ret, "b", "b", "=q", 1);
if (likely(!ret))
@@ -201,7 +201,7 @@ int __copy_in_user(void __user *dst, con
}
case 2: {
u16 tmp;
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(tmp, (u16 __user *)src,
ret, "w", "w", "=r", 2);
if (likely(!ret))
@@ -213,7 +213,7 @@ int __copy_in_user(void __user *dst, con
case 4: {
u32 tmp;
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(tmp, (u32 __user *)src,
ret, "l", "k", "=r", 4);
if (likely(!ret))
@@ -224,7 +224,7 @@ int __copy_in_user(void __user *dst, con
}
case 8: {
u64 tmp;
- __uaccess_begin();
+ __uaccess_begin_nospec();
__get_user_asm(tmp, (u64 __user *)src,
ret, "q", "", "=r", 8);
if (likely(!ret))
--- a/arch/x86/lib/usercopy_32.c
+++ b/arch/x86/lib/usercopy_32.c
@@ -570,7 +570,7 @@ do { \
unsigned long __copy_to_user_ll(void __user *to, const void *from,
unsigned long n)
{
- __uaccess_begin();
+ __uaccess_begin_nospec();
if (movsl_is_ok(to, from, n))
__copy_user(to, from, n);
else
@@ -583,7 +583,7 @@ EXPORT_SYMBOL(__copy_to_user_ll);
unsigned long __copy_from_user_ll(void *to, const void __user *from,
unsigned long n)
{
- __uaccess_begin();
+ __uaccess_begin_nospec();
if (movsl_is_ok(to, from, n))
__copy_user_zeroing(to, from, n);
else
@@ -596,7 +596,7 @@ EXPORT_SYMBOL(__copy_from_user_ll);
unsigned long __copy_from_user_ll_nozero(void *to, const void __user *from,
unsigned long n)
{
- __uaccess_begin();
+ __uaccess_begin_nospec();
if (movsl_is_ok(to, from, n))
__copy_user(to, from, n);
else
@@ -610,7 +610,7 @@ EXPORT_SYMBOL(__copy_from_user_ll_nozero
unsigned long __copy_from_user_ll_nocache(void *to, const void __user *from,
unsigned long n)
{
- __uaccess_begin();
+ __uaccess_begin_nospec();
#ifdef CONFIG_X86_INTEL_USERCOPY
if (n > 64 && cpu_has_xmm2)
n = __copy_user_zeroing_intel_nocache(to, from, n);
@@ -627,7 +627,7 @@ EXPORT_SYMBOL(__copy_from_user_ll_nocach
unsigned long __copy_from_user_ll_nocache_nozero(void *to, const void __user *from,
unsigned long n)
{
- __uaccess_begin();
+ __uaccess_begin_nospec();
#ifdef CONFIG_X86_INTEL_USERCOPY
if (n > 64 && cpu_has_xmm2)
n = __copy_user_intel_nocache(to, from, n);
next prev parent reply other threads:[~2018-03-12 3:06 UTC|newest]
Thread overview: 81+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-03-12 3:06 [PATCH 3.16 00/76] 3.16.56-rc1 review Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 67/76] x86/spectre: Fix an error message Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 68/76] nospec: Move array_index_nospec() parameter checking into separate macro Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 12/76] sysfs/cpu: Fix typos in vulnerability documentation Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 06/76] x86/cpu, x86/pti: Do not enable PTI on AMD processors Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 14/76] x86/alternatives: Fix ALTERNATIVE_2 padding generation properly Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 41/76] x86/retpoline: Fill RSB on context switch for affected CPUs Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 73/76] x86: Introduce __uaccess_begin_nospec() and uaccess_try_nospec Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 34/76] x86/retpoline: Add LFENCE to the retpoline/RSB filling RSB macros Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 01/76] kvm: vmx: Scrub hardware GPRs at VM-exit Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 30/76] x86/retpoline/checksum32: Convert assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 42/76] x86/cpu: Change type of x86_cache_size variable to unsigned int Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 56/76] x86/syscall: Sanitize syscall table de-references under speculation Ben Hutchings
2018-03-12 7:32 ` Jiri Slaby
2018-03-19 0:59 ` Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 07/76] x86/pti: Rename BUG_CPU_INSECURE to BUG_CPU_MELTDOWN Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 51/76] Documentation: Document array_index_nospec Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 49/76] x86/cpu/bugs: Make retpoline module warning conditional Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 32/76] x86/retpoline: Fill return stack buffer on vmexit Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 76/76] x86: fix build warnign with 32-bit PAE Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 72/76] x86: fix SMAP in 32-bit environments Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 60/76] x86/spectre: Fix spelling mistake: "vunerable"-> "vulnerable" Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 65/76] x86/speculation: Fix typo IBRS_ATT, which should be IBRS_ALL Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 71/76] x86: reorganize SMAP handling in user space accesses Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 63/76] x86/retpoline: Avoid retpolines for built-in __init functions Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 19/76] x86/asm: Make asm/alternative.h safe from assembly Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 37/76] kprobes/x86: Disable optimizing on the function jumps to indirect thunk Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 03/76] x86/cpu: Factor out application of forced CPU caps Ben Hutchings
2018-03-12 3:06 ` Ben Hutchings [this message]
2018-03-12 3:06 ` [PATCH 3.16 48/76] x86/bugs: Drop one "mitigation" from dmesg Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 54/76] x86: Introduce barrier_nospec Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 25/76] x86/retpoline/crypto: Convert crypto assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 66/76] x86/cpufeatures: Clean up Spectre v2 related CPUID flags Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 05/76] x86/cpufeatures: Add X86_BUG_CPU_INSECURE Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 15/76] x86/alternatives: Make optimize_nops() interrupt safe and synced Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 10/76] sysfs/cpu: Add vulnerability folder Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 57/76] vfs, fdtable: Prevent bounds-check bypass via speculative execution Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 70/76] nospec: Include <asm/barrier.h> dependency Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 17/76] x86/cpu/AMD: Make LFENCE a serializing instruction Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 64/76] x86/spectre: Simplify spectre_v2 command line parsing Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 22/76] x86/asm: Use register variable to get stack pointer value Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 26/76] x86/retpoline/entry: Convert entry assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 40/76] x86/cpu/intel: Introduce macros for Intel family numbers Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 04/76] x86/cpufeatures: Make CPU bugs sticky Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 43/76] x86/retpoline: Remove the esp/rsp thunk Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 21/76] x86: Clean up current_stack_pointer Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 20/76] kconfig.h: use __is_defined() to check if MODULE is defined Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 16/76] x86/alternatives: Fix optimize_nops() checking Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 59/76] x86/spectre: Report get_user mitigation for spectre_v1 Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 23/76] x86/retpoline: Add initial retpoline support Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 27/76] x86/retpoline/ftrace: Convert ftrace assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 61/76] x86/paravirt: Remove 'noreplace-paravirt' cmdline option Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 62/76] x86/kvm: Update spectre-v1 mitigation Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 33/76] x86/retpoline: Remove compile time warning Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 69/76] nospec: Kill array_index_nospec_mask_check() Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 31/76] x86/retpoline/irq32: Convert assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 39/76] x86/retpoline: Optimize inline assembler for vmexit_fill_RSB Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 45/76] KVM: VMX: Make indirect call speculation safe Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 18/76] x86/cpu/AMD: Use LFENCE_RDTSC in preference to MFENCE_RDTSC Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 44/76] KVM: x86: Make indirect calls in emulator speculation safe Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 46/76] module/retpoline: Warn about missing retpoline in module Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 29/76] x86/retpoline/xen: Convert Xen hypercall indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 13/76] x86/alternatives: Guard NOPs optimization Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 38/76] x86/pti: Document fix wrong index Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 08/76] x86/cpufeatures: Add X86_BUG_SPECTRE_V[12] Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 24/76] x86/spectre: Add boot time option to select Spectre v2 mitigation Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 28/76] x86/retpoline/hyperv: Convert assembler indirect jumps Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 58/76] nl80211: Sanitize array index in parse_txq_params Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 09/76] x86/cpu: Merge bugs.c and bugs_64.c Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 36/76] kprobes/x86: Blacklist indirect thunk functions for kprobes Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 55/76] x86/get_user: Use pointer masking to limit speculation Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 74/76] x86/usercopy: Replace open coded stac/clac with __uaccess_{begin, end} Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 11/76] x86/cpu: Implement CPU vulnerabilites sysfs functions Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 53/76] x86: Implement array_index_mask_nospec Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 02/76] x86/Documentation: Add PTI description Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 47/76] x86/nospec: Fix header guards names Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 52/76] array_index_nospec: Sanitize speculative array de-references Ben Hutchings
2018-03-12 3:06 ` [PATCH 3.16 35/76] retpoline: Introduce start/end markers of indirect thunk Ben Hutchings
2018-03-12 15:00 ` [PATCH 3.16 00/76] 3.16.56-rc1 review Guenter Roeck
2018-03-12 16:45 ` Guenter Roeck
2018-03-20 17:25 ` Ben Hutchings
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