linux/arch/powerpc/kernel/security.c
Linus Torvalds c90fca951e powerpc updates for 4.18
Notable changes:
 
  - Support for split PMD page table lock on 64-bit Book3S (Power8/9).
 
  - Add support for HAVE_RELIABLE_STACKTRACE, so we properly support live
    patching again.
 
  - Add support for patching barrier_nospec in copy_from_user() and syscall entry.
 
  - A couple of fixes for our data breakpoints on Book3S.
 
  - A series from Nick optimising TLB/mm handling with the Radix MMU.
 
  - Numerous small cleanups to squash sparse/gcc warnings from Mathieu Malaterre.
 
  - Several series optimising various parts of the 32-bit code from Christophe Leroy.
 
  - Removal of support for two old machines, "SBC834xE" and "C2K" ("GEFanuc,C2K"),
    which is why the diffstat has so many deletions.
 
 And many other small improvements & fixes.
 
 There's a few out-of-area changes. Some minor ftrace changes OK'ed by Steve, and
 a fix to our powernv cpuidle driver. Then there's a series touching mm, x86 and
 fs/proc/task_mmu.c, which cleans up some details around pkey support. It was
 ack'ed/reviewed by Ingo & Dave and has been in next for several weeks.
 
 Thanks to:
   Akshay Adiga, Alastair D'Silva, Alexey Kardashevskiy, Al Viro, Andrew
   Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Arnd Bergmann, Balbir Singh,
   Cédric Le Goater, Christophe Leroy, Christophe Lombard, Colin Ian King, Dave
   Hansen, Fabio Estevam, Finn Thain, Frederic Barrat, Gautham R. Shenoy, Haren
   Myneni, Hari Bathini, Ingo Molnar, Jonathan Neuschäfer, Josh Poimboeuf,
   Kamalesh Babulal, Madhavan Srinivasan, Mahesh Salgaonkar, Mark Greer, Mathieu
   Malaterre, Matthew Wilcox, Michael Neuling, Michal Suchanek, Naveen N. Rao,
   Nicholas Piggin, Nicolai Stange, Olof Johansson, Paul Gortmaker, Paul
   Mackerras, Peter Rosin, Pridhiviraj Paidipeddi, Ram Pai, Rashmica Gupta, Ravi
   Bangoria, Russell Currey, Sam Bobroff, Samuel Mendoza-Jonas, Segher
   Boessenkool, Shilpasri G Bhat, Simon Guo, Souptick Joarder, Stewart Smith,
   Thiago Jung Bauermann, Torsten Duwe, Vaibhav Jain, Wei Yongjun, Wolfram Sang,
   Yisheng Xie, YueHaibing.
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Merge tag 'powerpc-4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux

Pull powerpc updates from Michael Ellerman:
 "Notable changes:

   - Support for split PMD page table lock on 64-bit Book3S (Power8/9).

   - Add support for HAVE_RELIABLE_STACKTRACE, so we properly support
     live patching again.

   - Add support for patching barrier_nospec in copy_from_user() and
     syscall entry.

   - A couple of fixes for our data breakpoints on Book3S.

   - A series from Nick optimising TLB/mm handling with the Radix MMU.

   - Numerous small cleanups to squash sparse/gcc warnings from Mathieu
     Malaterre.

   - Several series optimising various parts of the 32-bit code from
     Christophe Leroy.

   - Removal of support for two old machines, "SBC834xE" and "C2K"
     ("GEFanuc,C2K"), which is why the diffstat has so many deletions.

  And many other small improvements & fixes.

  There's a few out-of-area changes. Some minor ftrace changes OK'ed by
  Steve, and a fix to our powernv cpuidle driver. Then there's a series
  touching mm, x86 and fs/proc/task_mmu.c, which cleans up some details
  around pkey support. It was ack'ed/reviewed by Ingo & Dave and has
  been in next for several weeks.

  Thanks to: Akshay Adiga, Alastair D'Silva, Alexey Kardashevskiy, Al
  Viro, Andrew Donnellan, Aneesh Kumar K.V, Anju T Sudhakar, Arnd
  Bergmann, Balbir Singh, Cédric Le Goater, Christophe Leroy, Christophe
  Lombard, Colin Ian King, Dave Hansen, Fabio Estevam, Finn Thain,
  Frederic Barrat, Gautham R. Shenoy, Haren Myneni, Hari Bathini, Ingo
  Molnar, Jonathan Neuschäfer, Josh Poimboeuf, Kamalesh Babulal,
  Madhavan Srinivasan, Mahesh Salgaonkar, Mark Greer, Mathieu Malaterre,
  Matthew Wilcox, Michael Neuling, Michal Suchanek, Naveen N. Rao,
  Nicholas Piggin, Nicolai Stange, Olof Johansson, Paul Gortmaker, Paul
  Mackerras, Peter Rosin, Pridhiviraj Paidipeddi, Ram Pai, Rashmica
  Gupta, Ravi Bangoria, Russell Currey, Sam Bobroff, Samuel
  Mendoza-Jonas, Segher Boessenkool, Shilpasri G Bhat, Simon Guo,
  Souptick Joarder, Stewart Smith, Thiago Jung Bauermann, Torsten Duwe,
  Vaibhav Jain, Wei Yongjun, Wolfram Sang, Yisheng Xie, YueHaibing"

* tag 'powerpc-4.18-1' of git://git.kernel.org/pub/scm/linux/kernel/git/powerpc/linux: (251 commits)
  powerpc/64s/radix: Fix missing ptesync in flush_cache_vmap
  cpuidle: powernv: Fix promotion from snooze if next state disabled
  powerpc: fix build failure by disabling attribute-alias warning in pci_32
  ocxl: Fix missing unlock on error in afu_ioctl_enable_p9_wait()
  powerpc-opal: fix spelling mistake "Uniterrupted" -> "Uninterrupted"
  powerpc: fix spelling mistake: "Usupported" -> "Unsupported"
  powerpc/pkeys: Detach execute_only key on !PROT_EXEC
  powerpc/powernv: copy/paste - Mask SO bit in CR
  powerpc: Remove core support for Marvell mv64x60 hostbridges
  powerpc/boot: Remove core support for Marvell mv64x60 hostbridges
  powerpc/boot: Remove support for Marvell mv64x60 i2c controller
  powerpc/boot: Remove support for Marvell MPSC serial controller
  powerpc/embedded6xx: Remove C2K board support
  powerpc/lib: optimise PPC32 memcmp
  powerpc/lib: optimise 32 bits __clear_user()
  powerpc/time: inline arch_vtime_task_switch()
  powerpc/Makefile: set -mcpu=860 flag for the 8xx
  powerpc: Implement csum_ipv6_magic in assembly
  powerpc/32: Optimise __csum_partial()
  powerpc/lib: Adjust .balign inside string functions for PPC32
  ...
2018-06-07 10:23:33 -07:00

309 lines
7.3 KiB
C

// SPDX-License-Identifier: GPL-2.0+
//
// Security related flags and so on.
//
// Copyright 2018, Michael Ellerman, IBM Corporation.
#include <linux/kernel.h>
#include <linux/device.h>
#include <linux/seq_buf.h>
#include <asm/debugfs.h>
#include <asm/security_features.h>
#include <asm/setup.h>
unsigned long powerpc_security_features __read_mostly = SEC_FTR_DEFAULT;
bool barrier_nospec_enabled;
static void enable_barrier_nospec(bool enable)
{
barrier_nospec_enabled = enable;
do_barrier_nospec_fixups(enable);
}
void setup_barrier_nospec(void)
{
bool enable;
/*
* It would make sense to check SEC_FTR_SPEC_BAR_ORI31 below as well.
* But there's a good reason not to. The two flags we check below are
* both are enabled by default in the kernel, so if the hcall is not
* functional they will be enabled.
* On a system where the host firmware has been updated (so the ori
* functions as a barrier), but on which the hypervisor (KVM/Qemu) has
* not been updated, we would like to enable the barrier. Dropping the
* check for SEC_FTR_SPEC_BAR_ORI31 achieves that. The only downside is
* we potentially enable the barrier on systems where the host firmware
* is not updated, but that's harmless as it's a no-op.
*/
enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR);
enable_barrier_nospec(enable);
}
#ifdef CONFIG_DEBUG_FS
static int barrier_nospec_set(void *data, u64 val)
{
switch (val) {
case 0:
case 1:
break;
default:
return -EINVAL;
}
if (!!val == !!barrier_nospec_enabled)
return 0;
enable_barrier_nospec(!!val);
return 0;
}
static int barrier_nospec_get(void *data, u64 *val)
{
*val = barrier_nospec_enabled ? 1 : 0;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_barrier_nospec,
barrier_nospec_get, barrier_nospec_set, "%llu\n");
static __init int barrier_nospec_debugfs_init(void)
{
debugfs_create_file("barrier_nospec", 0600, powerpc_debugfs_root, NULL,
&fops_barrier_nospec);
return 0;
}
device_initcall(barrier_nospec_debugfs_init);
#endif /* CONFIG_DEBUG_FS */
ssize_t cpu_show_meltdown(struct device *dev, struct device_attribute *attr, char *buf)
{
bool thread_priv;
thread_priv = security_ftr_enabled(SEC_FTR_L1D_THREAD_PRIV);
if (rfi_flush || thread_priv) {
struct seq_buf s;
seq_buf_init(&s, buf, PAGE_SIZE - 1);
seq_buf_printf(&s, "Mitigation: ");
if (rfi_flush)
seq_buf_printf(&s, "RFI Flush");
if (rfi_flush && thread_priv)
seq_buf_printf(&s, ", ");
if (thread_priv)
seq_buf_printf(&s, "L1D private per thread");
seq_buf_printf(&s, "\n");
return s.len;
}
if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
!security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
return sprintf(buf, "Not affected\n");
return sprintf(buf, "Vulnerable\n");
}
ssize_t cpu_show_spectre_v1(struct device *dev, struct device_attribute *attr, char *buf)
{
if (!security_ftr_enabled(SEC_FTR_BNDS_CHK_SPEC_BAR))
return sprintf(buf, "Not affected\n");
if (barrier_nospec_enabled)
return sprintf(buf, "Mitigation: __user pointer sanitization\n");
return sprintf(buf, "Vulnerable\n");
}
ssize_t cpu_show_spectre_v2(struct device *dev, struct device_attribute *attr, char *buf)
{
bool bcs, ccd, ori;
struct seq_buf s;
seq_buf_init(&s, buf, PAGE_SIZE - 1);
bcs = security_ftr_enabled(SEC_FTR_BCCTRL_SERIALISED);
ccd = security_ftr_enabled(SEC_FTR_COUNT_CACHE_DISABLED);
ori = security_ftr_enabled(SEC_FTR_SPEC_BAR_ORI31);
if (bcs || ccd) {
seq_buf_printf(&s, "Mitigation: ");
if (bcs)
seq_buf_printf(&s, "Indirect branch serialisation (kernel only)");
if (bcs && ccd)
seq_buf_printf(&s, ", ");
if (ccd)
seq_buf_printf(&s, "Indirect branch cache disabled");
} else
seq_buf_printf(&s, "Vulnerable");
if (ori)
seq_buf_printf(&s, ", ori31 speculation barrier enabled");
seq_buf_printf(&s, "\n");
return s.len;
}
/*
* Store-forwarding barrier support.
*/
static enum stf_barrier_type stf_enabled_flush_types;
static bool no_stf_barrier;
bool stf_barrier;
static int __init handle_no_stf_barrier(char *p)
{
pr_info("stf-barrier: disabled on command line.");
no_stf_barrier = true;
return 0;
}
early_param("no_stf_barrier", handle_no_stf_barrier);
/* This is the generic flag used by other architectures */
static int __init handle_ssbd(char *p)
{
if (!p || strncmp(p, "auto", 5) == 0 || strncmp(p, "on", 2) == 0 ) {
/* Until firmware tells us, we have the barrier with auto */
return 0;
} else if (strncmp(p, "off", 3) == 0) {
handle_no_stf_barrier(NULL);
return 0;
} else
return 1;
return 0;
}
early_param("spec_store_bypass_disable", handle_ssbd);
/* This is the generic flag used by other architectures */
static int __init handle_no_ssbd(char *p)
{
handle_no_stf_barrier(NULL);
return 0;
}
early_param("nospec_store_bypass_disable", handle_no_ssbd);
static void stf_barrier_enable(bool enable)
{
if (enable)
do_stf_barrier_fixups(stf_enabled_flush_types);
else
do_stf_barrier_fixups(STF_BARRIER_NONE);
stf_barrier = enable;
}
void setup_stf_barrier(void)
{
enum stf_barrier_type type;
bool enable, hv;
hv = cpu_has_feature(CPU_FTR_HVMODE);
/* Default to fallback in case fw-features are not available */
if (cpu_has_feature(CPU_FTR_ARCH_300))
type = STF_BARRIER_EIEIO;
else if (cpu_has_feature(CPU_FTR_ARCH_207S))
type = STF_BARRIER_SYNC_ORI;
else if (cpu_has_feature(CPU_FTR_ARCH_206))
type = STF_BARRIER_FALLBACK;
else
type = STF_BARRIER_NONE;
enable = security_ftr_enabled(SEC_FTR_FAVOUR_SECURITY) &&
(security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR) ||
(security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) && hv));
if (type == STF_BARRIER_FALLBACK) {
pr_info("stf-barrier: fallback barrier available\n");
} else if (type == STF_BARRIER_SYNC_ORI) {
pr_info("stf-barrier: hwsync barrier available\n");
} else if (type == STF_BARRIER_EIEIO) {
pr_info("stf-barrier: eieio barrier available\n");
}
stf_enabled_flush_types = type;
if (!no_stf_barrier)
stf_barrier_enable(enable);
}
ssize_t cpu_show_spec_store_bypass(struct device *dev, struct device_attribute *attr, char *buf)
{
if (stf_barrier && stf_enabled_flush_types != STF_BARRIER_NONE) {
const char *type;
switch (stf_enabled_flush_types) {
case STF_BARRIER_EIEIO:
type = "eieio";
break;
case STF_BARRIER_SYNC_ORI:
type = "hwsync";
break;
case STF_BARRIER_FALLBACK:
type = "fallback";
break;
default:
type = "unknown";
}
return sprintf(buf, "Mitigation: Kernel entry/exit barrier (%s)\n", type);
}
if (!security_ftr_enabled(SEC_FTR_L1D_FLUSH_HV) &&
!security_ftr_enabled(SEC_FTR_L1D_FLUSH_PR))
return sprintf(buf, "Not affected\n");
return sprintf(buf, "Vulnerable\n");
}
#ifdef CONFIG_DEBUG_FS
static int stf_barrier_set(void *data, u64 val)
{
bool enable;
if (val == 1)
enable = true;
else if (val == 0)
enable = false;
else
return -EINVAL;
/* Only do anything if we're changing state */
if (enable != stf_barrier)
stf_barrier_enable(enable);
return 0;
}
static int stf_barrier_get(void *data, u64 *val)
{
*val = stf_barrier ? 1 : 0;
return 0;
}
DEFINE_SIMPLE_ATTRIBUTE(fops_stf_barrier, stf_barrier_get, stf_barrier_set, "%llu\n");
static __init int stf_barrier_debugfs_init(void)
{
debugfs_create_file("stf_barrier", 0600, powerpc_debugfs_root, NULL, &fops_stf_barrier);
return 0;
}
device_initcall(stf_barrier_debugfs_init);
#endif /* CONFIG_DEBUG_FS */