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3b05a1e517
"powerpc_security_features" is "unsigned long", i.e. 32-bit or 64-bit,
depending on the platform (PPC_FSL_BOOK3E or PPC_BOOK3S_64). Hence
casting its address to "u64 *", and calling debugfs_create_x64() is
wrong, and leaks 32-bit of nearby data to userspace on 32-bit platforms.
While all currently defined SEC_FTR_* security feature flags fit in
32-bit, they all have "ULL" suffixes to make them 64-bit constants.
Hence fix the leak by changing the type of "powerpc_security_features"
(and the parameter types of its accessors) to "u64". This also allows
to drop the cast.
Fixes: 398af57112 ("powerpc/security: Show powerpc_security_features in debugfs")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Link: https://lore.kernel.org/r/20191021142309.28105-1-geert+renesas@glider.be
92 lines
2.6 KiB
C
92 lines
2.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0+ */
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/*
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* Security related feature bit definitions.
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*
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* Copyright 2018, Michael Ellerman, IBM Corporation.
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*/
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#ifndef _ASM_POWERPC_SECURITY_FEATURES_H
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#define _ASM_POWERPC_SECURITY_FEATURES_H
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extern u64 powerpc_security_features;
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extern bool rfi_flush;
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/* These are bit flags */
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enum stf_barrier_type {
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STF_BARRIER_NONE = 0x1,
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STF_BARRIER_FALLBACK = 0x2,
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STF_BARRIER_EIEIO = 0x4,
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STF_BARRIER_SYNC_ORI = 0x8,
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};
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void setup_stf_barrier(void);
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void do_stf_barrier_fixups(enum stf_barrier_type types);
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void setup_count_cache_flush(void);
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static inline void security_ftr_set(u64 feature)
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{
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powerpc_security_features |= feature;
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}
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static inline void security_ftr_clear(u64 feature)
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{
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powerpc_security_features &= ~feature;
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}
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static inline bool security_ftr_enabled(u64 feature)
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{
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return !!(powerpc_security_features & feature);
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}
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// Features indicating support for Spectre/Meltdown mitigations
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// The L1-D cache can be flushed with ori r30,r30,0
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#define SEC_FTR_L1D_FLUSH_ORI30 0x0000000000000001ull
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// The L1-D cache can be flushed with mtspr 882,r0 (aka SPRN_TRIG2)
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#define SEC_FTR_L1D_FLUSH_TRIG2 0x0000000000000002ull
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// ori r31,r31,0 acts as a speculation barrier
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#define SEC_FTR_SPEC_BAR_ORI31 0x0000000000000004ull
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// Speculation past bctr is disabled
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#define SEC_FTR_BCCTRL_SERIALISED 0x0000000000000008ull
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// Entries in L1-D are private to a SMT thread
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#define SEC_FTR_L1D_THREAD_PRIV 0x0000000000000010ull
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// Indirect branch prediction cache disabled
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#define SEC_FTR_COUNT_CACHE_DISABLED 0x0000000000000020ull
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// bcctr 2,0,0 triggers a hardware assisted count cache flush
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#define SEC_FTR_BCCTR_FLUSH_ASSIST 0x0000000000000800ull
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// Features indicating need for Spectre/Meltdown mitigations
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// The L1-D cache should be flushed on MSR[HV] 1->0 transition (hypervisor to guest)
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#define SEC_FTR_L1D_FLUSH_HV 0x0000000000000040ull
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// The L1-D cache should be flushed on MSR[PR] 0->1 transition (kernel to userspace)
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#define SEC_FTR_L1D_FLUSH_PR 0x0000000000000080ull
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// A speculation barrier should be used for bounds checks (Spectre variant 1)
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#define SEC_FTR_BNDS_CHK_SPEC_BAR 0x0000000000000100ull
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// Firmware configuration indicates user favours security over performance
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#define SEC_FTR_FAVOUR_SECURITY 0x0000000000000200ull
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// Software required to flush count cache on context switch
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#define SEC_FTR_FLUSH_COUNT_CACHE 0x0000000000000400ull
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// Features enabled by default
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#define SEC_FTR_DEFAULT \
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(SEC_FTR_L1D_FLUSH_HV | \
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SEC_FTR_L1D_FLUSH_PR | \
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SEC_FTR_BNDS_CHK_SPEC_BAR | \
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SEC_FTR_FAVOUR_SECURITY)
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#endif /* _ASM_POWERPC_SECURITY_FEATURES_H */
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