0d1a8a16e6
commit a09a6e2399ba0595c3042b3164f3ca68a3cff33e upstream. Since entry asm is tricky, add a validation pass that ensures the retbleed mitigation has been done before the first actual RET instruction. Entry points are those that either have UNWIND_HINT_ENTRY, which acts as UNWIND_HINT_EMPTY but marks the instruction as an entry point, or those that have UWIND_HINT_IRET_REGS at +0. This is basically a variant of validate_branch() that is intra-function and it will simply follow all branches from marked entry points and ensures that all paths lead to ANNOTATE_UNRET_END. If a path hits RET or an indirection the path is a fail and will be reported. There are 3 ANNOTATE_UNRET_END instances: - UNTRAIN_RET itself - exception from-kernel; this path doesn't need UNTRAIN_RET - all early exceptions; these also don't need UNTRAIN_RET Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Signed-off-by: Borislav Petkov <bp@suse.de> Reviewed-by: Josh Poimboeuf <jpoimboe@kernel.org> Signed-off-by: Borislav Petkov <bp@suse.de> [cascardo: arch/x86/entry/entry_64.S no pt_regs return at .Lerror_entry_done_lfence] [cascardo: tools/objtool/builtin-check.c no link option validation] [cascardo: tools/objtool/check.c opts.ibt is ibt] [cascardo: tools/objtool/include/objtool/builtin.h leave unret option as bool, no struct opts] [cascardo: objtool is still called from scripts/link-vmlinux.sh] [cascardo: no IBT support] Signed-off-by: Thadeu Lima de Souza Cascardo <cascardo@canonical.com> [bwh: Backported to 5.10: - In scripts/link-vmlinux.sh, use "test -n" instead of is_enabled - Adjust context] Signed-off-by: Ben Hutchings <ben@decadent.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
62 lines
1.3 KiB
C
62 lines
1.3 KiB
C
#ifndef _ASM_X86_UNWIND_HINTS_H
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#define _ASM_X86_UNWIND_HINTS_H
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#include <linux/objtool.h>
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#include "orc_types.h"
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#ifdef __ASSEMBLY__
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.macro UNWIND_HINT_EMPTY
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UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_CALL end=1
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.endm
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.macro UNWIND_HINT_ENTRY
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UNWIND_HINT sp_reg=ORC_REG_UNDEFINED type=UNWIND_HINT_TYPE_ENTRY end=1
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.endm
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.macro UNWIND_HINT_REGS base=%rsp offset=0 indirect=0 extra=1 partial=0
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.if \base == %rsp
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.if \indirect
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.set sp_reg, ORC_REG_SP_INDIRECT
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.else
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.set sp_reg, ORC_REG_SP
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.endif
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.elseif \base == %rbp
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.set sp_reg, ORC_REG_BP
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.elseif \base == %rdi
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.set sp_reg, ORC_REG_DI
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.elseif \base == %rdx
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.set sp_reg, ORC_REG_DX
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.elseif \base == %r10
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.set sp_reg, ORC_REG_R10
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.else
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.error "UNWIND_HINT_REGS: bad base register"
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.endif
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.set sp_offset, \offset
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.if \partial
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.set type, UNWIND_HINT_TYPE_REGS_PARTIAL
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.elseif \extra == 0
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.set type, UNWIND_HINT_TYPE_REGS_PARTIAL
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.set sp_offset, \offset + (16*8)
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.else
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.set type, UNWIND_HINT_TYPE_REGS
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.endif
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UNWIND_HINT sp_reg=sp_reg sp_offset=sp_offset type=type
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.endm
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.macro UNWIND_HINT_IRET_REGS base=%rsp offset=0
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UNWIND_HINT_REGS base=\base offset=\offset partial=1
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.endm
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.macro UNWIND_HINT_FUNC
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UNWIND_HINT sp_reg=ORC_REG_SP sp_offset=8 type=UNWIND_HINT_TYPE_FUNC
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.endm
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#endif /* __ASSEMBLY__ */
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#endif /* _ASM_X86_UNWIND_HINTS_H */
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