Patch "powerpc/pseries: Fix clearing of security feature flags" has been added to the 4.4-stable tree

Mon Apr 29 19:51:28 AEST 2019

This is a note to let you know that I've just added the patch titled

    powerpc/pseries: Fix clearing of security feature flags

to the 4.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     powerpc-pseries-fix-clearing-of-security-feature-flags.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable at vger.kernel.org> know about it.


>From foo at baz Mon 29 Apr 2019 11:38:37 AM CEST
From: Michael Ellerman <mpe at ellerman.id.au>
Date: Mon, 22 Apr 2019 00:20:05 +1000
Subject: powerpc/pseries: Fix clearing of security feature flags
To: stable at vger.kernel.org, gregkh at linuxfoundation.org
Cc: linuxppc-dev at ozlabs.org, diana.craciun at nxp.com, msuchanek at suse.de, npiggin at gmail.com, christophe.leroy at c-s.fr
Message-ID: <20190421142037.21881-21-mpe at ellerman.id.au>

From: Mauricio Faria de Oliveira <mauricfo at linux.vnet.ibm.com>

commit 0f9bdfe3c77091e8704d2e510eb7c2c2c6cde524 upstream.

The H_CPU_BEHAV_* flags should be checked for in the 'behaviour' field
of 'struct h_cpu_char_result' -- 'character' is for H_CPU_CHAR_*
flags.

Found by playing around with QEMU's implementation of the hypercall:

  H_CPU_CHAR=0xf000000000000000
  H_CPU_BEHAV=0x0000000000000000

  This clears H_CPU_BEHAV_FAVOUR_SECURITY and H_CPU_BEHAV_L1D_FLUSH_PR
  so pseries_setup_rfi_flush() disables 'rfi_flush'; and it also
  clears H_CPU_CHAR_L1D_THREAD_PRIV flag. So there is no RFI flush
  mitigation at all for cpu_show_meltdown() to report; but currently
  it does:

  Original kernel:

    # cat /sys/devices/system/cpu/vulnerabilities/meltdown
    Mitigation: RFI Flush

  Patched kernel:

    # cat /sys/devices/system/cpu/vulnerabilities/meltdown
    Not affected

  H_CPU_CHAR=0x0000000000000000
  H_CPU_BEHAV=0xf000000000000000

  This sets H_CPU_BEHAV_BNDS_CHK_SPEC_BAR so cpu_show_spectre_v1() should
  report vulnerable; but currently it doesn't:

  Original kernel:

    # cat /sys/devices/system/cpu/vulnerabilities/spectre_v1
    Not affected

  Patched kernel:

    # cat /sys/devices/system/cpu/vulnerabilities/spectre_v1
    Vulnerable

Brown-paper-bag-by: Michael Ellerman <mpe at ellerman.id.au>
Fixes: f636c14790ea ("powerpc/pseries: Set or clear security feature flags")
Signed-off-by: Mauricio Faria de Oliveira <mauricfo at linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe at ellerman.id.au>
Signed-off-by: Greg Kroah-Hartman <gregkh at linuxfoundation.org>
---
 arch/powerpc/platforms/pseries/setup.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/arch/powerpc/platforms/pseries/setup.c
+++ b/arch/powerpc/platforms/pseries/setup.c
@@ -524,13 +524,13 @@ static void init_cpu_char_feature_flags(
 	 * The features below are enabled by default, so we instead look to see
 	 * if firmware has *disabled* them, and clear them if so.
 	 */
-	if (!(result->character & H_CPU_BEHAV_FAVOUR_SECURITY))
+	if (!(result->behaviour & H_CPU_BEHAV_FAVOUR_SECURITY))
 		security_ftr_clear(SEC_FTR_FAVOUR_SECURITY);
 
-	if (!(result->character & H_CPU_BEHAV_L1D_FLUSH_PR))
+	if (!(result->behaviour & H_CPU_BEHAV_L1D_FLUSH_PR))
 		security_ftr_clear(SEC_FTR_L1D_FLUSH_PR);
 
-	if (!(result->character & H_CPU_BEHAV_BNDS_CHK_SPEC_BAR))
+	if (!(result->behaviour & H_CPU_BEHAV_BNDS_CHK_SPEC_BAR))
 		security_ftr_clear(SEC_FTR_BNDS_CHK_SPEC_BAR);
 }
 


Patches currently in stable-queue which might be from mpe at ellerman.id.au are

queue-4.4/powerpc-64s-add-support-for-a-store-forwarding-barrier-at-kernel-entry-exit.patch
queue-4.4/powerpc-64-make-stf-barrier-ppc_book3s_64-specific.patch
queue-4.4/powerpc-pseries-set-or-clear-security-feature-flags.patch
queue-4.4/powerpc-fsl-fix-spectre_v2-mitigations-reporting.patch
queue-4.4/powerpc-64s-patch-barrier_nospec-in-modules.patch
queue-4.4/powerpc-pseries-support-firmware-disable-of-rfi-flush.patch
queue-4.4/powerpc-rfi-flush-call-setup_rfi_flush-after-lpm-migration.patch
queue-4.4/powerpc-pseries-query-hypervisor-for-count-cache-flush-settings.patch
queue-4.4/powerpc-powernv-set-or-clear-security-feature-flags.patch
queue-4.4/powerpc-64s-add-support-for-software-count-cache-flush.patch
queue-4.4/powerpc64s-show-ori31-availability-in-spectre_v1-sysfs-file-not-v2.patch
queue-4.4/powerpc-fsl-flush-the-branch-predictor-at-each-kernel-entry-64bit.patch
queue-4.4/powerpc-fsl-update-spectre-v2-reporting.patch
queue-4.4/powerpc-64s-wire-up-cpu_show_spectre_v2.patch
queue-4.4/powerpc-64-make-meltdown-reporting-book3s-64-specific.patch
queue-4.4/powerpc-rfi-flush-make-it-possible-to-call-setup_rfi_flush-again.patch
queue-4.4/powerpc-64s-add-support-for-ori-barrier_nospec-patching.patch
queue-4.4/powerpc-use-barrier_nospec-in-copy_from_user.patch
queue-4.4/powerpc-64s-fix-section-mismatch-warnings-from-setup_rfi_flush.patch
queue-4.4/powerpc-avoid-code-patching-freed-init-sections.patch
queue-4.4/powerpc-fsl-add-macro-to-flush-the-branch-predictor.patch
queue-4.4/powerpc-xmon-add-rfi-flush-related-fields-to-paca-dump.patch
queue-4.4/powerpc-fsl-add-barrier_nospec-implementation-for-nxp-powerpc-book3e.patch
queue-4.4/powerpc-security-fix-spectre_v2-reporting.patch
queue-4.4/powerpc-add-security-feature-flags-for-spectre-meltdown.patch
queue-4.4/powerpc-powernv-use-the-security-flags-in-pnv_setup_rfi_flush.patch
queue-4.4/powerpc-64-disable-the-speculation-barrier-from-the-command-line.patch
queue-4.4/powerpc-fsl-fix-the-flush-of-branch-predictor.patch
queue-4.4/powerpc-pseries-use-the-security-flags-in-pseries_setup_rfi_flush.patch
queue-4.4/powerpc-64-add-config_ppc_barrier_nospec.patch
queue-4.4/powerpc-64s-move-cpu_show_meltdown.patch
queue-4.4/powerpc-64-use-barrier_nospec-in-syscall-entry.patch
queue-4.4/powerpc-fsl-add-nospectre_v2-command-line-argument.patch
queue-4.4/powerpc-64s-add-new-security-feature-flags-for-count-cache-flush.patch
queue-4.4/powerpc-fsl-add-infrastructure-to-fixup-branch-predictor-flush.patch
queue-4.4/powerpc-rfi-flush-differentiate-enabled-and-patched-flush-types.patch
queue-4.4/powerpc-64s-enhance-the-information-in-cpu_show_spectre_v1.patch
queue-4.4/powerpc-64-call-setup_barrier_nospec-from-setup_arch.patch
queue-4.4/powerpc-rfi-flush-always-enable-fallback-flush-on-pseries.patch
queue-4.4/powerpc-64s-improve-rfi-l1-d-cache-flush-fallback.patch
queue-4.4/powerpc-asm-add-a-patch_site-macro-helpers-for-patching-instructions.patch
queue-4.4/powerpc-pseries-add-new-h_get_cpu_characteristics-flags.patch
queue-4.4/powerpc-64s-enable-barrier_nospec-based-on-firmware-settings.patch
queue-4.4/powerpc-powernv-support-firmware-disable-of-rfi-flush.patch
queue-4.4/powerpc-rfi-flush-move-the-logic-to-avoid-a-redo-into-the-debugfs-code.patch
queue-4.4/powerpc-powernv-query-firmware-for-count-cache-flush-settings.patch
queue-4.4/powerpc-64s-wire-up-cpu_show_spectre_v1.patch
queue-4.4/powerpc-64s-add-barrier_nospec.patch
queue-4.4/powerpc-64s-enhance-the-information-in-cpu_show_meltdown.patch
queue-4.4/powerpc-move-default-security-feature-flags.patch
queue-4.4/powerpc-pseries-fix-clearing-of-security-feature-flags.patch
queue-4.4/powerpc-pseries-restore-default-security-feature-flags-on-setup.patch
