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1c33bb0507
Historically, signal.h defines MINSIGSTKSZ (2KB) and SIGSTKSZ (8KB), for
use by all architectures with sigaltstack(2). Over time, the hardware state
size grew, but these constants did not evolve. Today, literal use of these
constants on several architectures may result in signal stack overflow, and
thus user data corruption.
A few years ago, the ARM team addressed this issue by establishing
getauxval(AT_MINSIGSTKSZ). This enables the kernel to supply a value
at runtime that is an appropriate replacement on current and future
hardware.
Add getauxval(AT_MINSIGSTKSZ) support to x86, analogous to the support
added for ARM in
94b07c1f8c ("arm64: signal: Report signal frame size to userspace via auxv").
Also, include a documentation to describe x86-specific auxiliary vectors.
Signed-off-by: Chang S. Bae <chang.seok.bae@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Len Brown <len.brown@intel.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20210518200320.17239-4-chang.seok.bae@intel.com
20 lines
546 B
C
20 lines
546 B
C
/* SPDX-License-Identifier: GPL-2.0 WITH Linux-syscall-note */
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#ifndef _ASM_X86_AUXVEC_H
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#define _ASM_X86_AUXVEC_H
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/*
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* Architecture-neutral AT_ values in 0-17, leave some room
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* for more of them, start the x86-specific ones at 32.
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*/
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#ifdef __i386__
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#define AT_SYSINFO 32
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#endif
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#define AT_SYSINFO_EHDR 33
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/* entries in ARCH_DLINFO: */
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#if defined(CONFIG_IA32_EMULATION) || !defined(CONFIG_X86_64)
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# define AT_VECTOR_SIZE_ARCH 3
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#else /* else it's non-compat x86-64 */
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# define AT_VECTOR_SIZE_ARCH 2
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#endif
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#endif /* _ASM_X86_AUXVEC_H */
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