From: Mauricio Faria de Oliveira Date: Sat, 26 May 2018 04:27:47 +0000 (+1000) Subject: powerpc/pseries: Restore default security feature flags on setup X-Git-Tag: v4.14.45~439 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=1618f211f96e3725615074a92f05dfe19be53b44;p=platform%2Fkernel%2Flinux-rpi.git powerpc/pseries: Restore default security feature flags on setup commit 6232774f1599028a15418179d17f7df47ede770a upstream. After migration the security feature flags might have changed (e.g., destination system with unpatched firmware), but some flags are not set/clear again in init_cpu_char_feature_flags() because it assumes the security flags to be the defaults. Additionally, if the H_GET_CPU_CHARACTERISTICS hypercall fails then init_cpu_char_feature_flags() does not run again, which potentially might leave the system in an insecure or sub-optimal configuration. So, just restore the security feature flags to the defaults assumed by init_cpu_char_feature_flags() so it can set/clear them correctly, and to ensure safe settings are in place in case the hypercall fail. Fixes: f636c14790ea ("powerpc/pseries: Set or clear security feature flags") Depends-on: 19887d6a28e2 ("powerpc: Move default security feature flags") Signed-off-by: Mauricio Faria de Oliveira Signed-off-by: Michael Ellerman Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/powerpc/platforms/pseries/setup.c b/arch/powerpc/platforms/pseries/setup.c index 3cb12d27f1..1973de3 100644 --- a/arch/powerpc/platforms/pseries/setup.c +++ b/arch/powerpc/platforms/pseries/setup.c @@ -462,6 +462,10 @@ static void __init find_and_init_phbs(void) static void init_cpu_char_feature_flags(struct h_cpu_char_result *result) { + /* + * The features below are disabled by default, so we instead look to see + * if firmware has *enabled* them, and set them if so. + */ if (result->character & H_CPU_CHAR_SPEC_BAR_ORI31) security_ftr_set(SEC_FTR_SPEC_BAR_ORI31); @@ -501,6 +505,13 @@ void pseries_setup_rfi_flush(void) bool enable; long rc; + /* + * Set features to the defaults assumed by init_cpu_char_feature_flags() + * so it can set/clear again any features that might have changed after + * migration, and in case the hypercall fails and it is not even called. + */ + powerpc_security_features = SEC_FTR_DEFAULT; + rc = plpar_get_cpu_characteristics(&result); if (rc == H_SUCCESS) init_cpu_char_feature_flags(&result);