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23ef9d4397
The kernel's CFI implementation uses the KCFI ABI specifically, and is not strictly tied to a particular compiler. In preparation for GCC supporting KCFI, rename CONFIG_CFI_CLANG to CONFIG_CFI (along with associated options). Use new "transitional" Kconfig option for old CONFIG_CFI_CLANG that will enable CONFIG_CFI during olddefconfig. Reviewed-by: Linus Walleij <linus.walleij@linaro.org> Reviewed-by: Nathan Chancellor <nathan@kernel.org> Link: https://lore.kernel.org/r/20250923213422.1105654-3-kees@kernel.org Signed-off-by: Kees Cook <kees@kernel.org>
87 lines
2.0 KiB
C
87 lines
2.0 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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/*
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* Clang Control Flow Integrity (CFI) support.
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*
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* Copyright (C) 2022 Google LLC
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*/
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#ifndef _LINUX_CFI_H
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#define _LINUX_CFI_H
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#include <linux/bug.h>
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#include <linux/module.h>
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#include <asm/cfi.h>
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#ifdef CONFIG_CFI
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extern bool cfi_warn;
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enum bug_trap_type report_cfi_failure(struct pt_regs *regs, unsigned long addr,
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unsigned long *target, u32 type);
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static inline enum bug_trap_type report_cfi_failure_noaddr(struct pt_regs *regs,
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unsigned long addr)
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{
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return report_cfi_failure(regs, addr, NULL, 0);
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}
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#ifndef cfi_get_offset
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/*
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* Returns the CFI prefix offset. By default, the compiler emits only
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* a 4-byte CFI type hash before the function. If an architecture
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* uses -fpatchable-function-entry=N,M where M>0 to change the prefix
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* offset, they must override this function.
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*/
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static inline int cfi_get_offset(void)
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{
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return 4;
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}
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#endif
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#ifndef cfi_get_func_hash
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static inline u32 cfi_get_func_hash(void *func)
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{
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u32 hash;
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if (get_kernel_nofault(hash, func - cfi_get_offset()))
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return 0;
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return hash;
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}
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#endif
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/* CFI type hashes for BPF function types */
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extern u32 cfi_bpf_hash;
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extern u32 cfi_bpf_subprog_hash;
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#else /* CONFIG_CFI */
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static inline int cfi_get_offset(void) { return 0; }
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static inline u32 cfi_get_func_hash(void *func) { return 0; }
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#define cfi_bpf_hash 0U
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#define cfi_bpf_subprog_hash 0U
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#endif /* CONFIG_CFI */
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#ifdef CONFIG_ARCH_USES_CFI_TRAPS
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bool is_cfi_trap(unsigned long addr);
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#else
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static inline bool is_cfi_trap(unsigned long addr) { return false; }
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#endif
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#ifdef CONFIG_MODULES
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#ifdef CONFIG_ARCH_USES_CFI_TRAPS
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void module_cfi_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs,
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struct module *mod);
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#else
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static inline void module_cfi_finalize(const Elf_Ehdr *hdr,
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const Elf_Shdr *sechdrs,
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struct module *mod) {}
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#endif /* CONFIG_ARCH_USES_CFI_TRAPS */
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#endif /* CONFIG_MODULES */
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#ifndef CFI_NOSEAL
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#define CFI_NOSEAL(x)
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#endif
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#endif /* _LINUX_CFI_H */
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