// SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 1991, 1992 Linus Torvalds * Copyright (C) 2000, 2001, 2002 Andi Kleen SuSE Labs * * 1997-11-28 Modified for POSIX.1b signals by Richard Henderson * 2000-06-20 Pentium III FXSR, SSE support by Gareth Hughes * 2000-2002 x86-64 support by Andi Kleen */ #define pr_fmt(fmt) … #include <linux/sched.h> #include <linux/sched/task_stack.h> #include <linux/mm.h> #include <linux/smp.h> #include <linux/kernel.h> #include <linux/kstrtox.h> #include <linux/errno.h> #include <linux/wait.h> #include <linux/unistd.h> #include <linux/stddef.h> #include <linux/personality.h> #include <linux/uaccess.h> #include <linux/user-return-notifier.h> #include <linux/uprobes.h> #include <linux/context_tracking.h> #include <linux/entry-common.h> #include <linux/syscalls.h> #include <linux/rseq.h> #include <asm/processor.h> #include <asm/ucontext.h> #include <asm/fpu/signal.h> #include <asm/fpu/xstate.h> #include <asm/vdso.h> #include <asm/mce.h> #include <asm/sighandling.h> #include <asm/vm86.h> #include <asm/syscall.h> #include <asm/sigframe.h> #include <asm/signal.h> #include <asm/shstk.h> static inline int is_ia32_compat_frame(struct ksignal *ksig) { … } static inline int is_ia32_frame(struct ksignal *ksig) { … } static inline int is_x32_frame(struct ksignal *ksig) { … } /* * Enable all pkeys temporarily, so as to ensure that both the current * execution stack as well as the alternate signal stack are writeable. * The application can use any of the available pkeys to protect the * alternate signal stack, and we don't know which one it is, so enable * all. The PKRU register will be reset to init_pkru later in the flow, * in fpu__clear_user_states(), and it is the application's responsibility * to enable the appropriate pkey as the first step in the signal handler * so that the handler does not segfault. */ static inline u32 sig_prepare_pkru(void) { … } /* * Set up a signal frame. */ /* x86 ABI requires 16-byte alignment */ #define FRAME_ALIGNMENT … #define MAX_FRAME_PADDING … /* * Determine which stack to use.. */ void __user * get_sigframe(struct ksignal *ksig, struct pt_regs *regs, size_t frame_size, void __user **fpstate) { … } /* * There are four different struct types for signal frame: sigframe_ia32, * rt_sigframe_ia32, rt_sigframe_x32, and rt_sigframe. Use the worst case * -- the largest size. It means the size for 64-bit apps is a bit more * than needed, but this keeps the code simple. */ #if defined(CONFIG_X86_32) || defined(CONFIG_IA32_EMULATION) #define MAX_FRAME_SIGINFO_UCTXT_SIZE … #else #define MAX_FRAME_SIGINFO_UCTXT_SIZE … #endif /* * The FP state frame contains an XSAVE buffer which must be 64-byte aligned. * If a signal frame starts at an unaligned address, extra space is required. * This is the max alignment padding, conservatively. */ #define MAX_XSAVE_PADDING … /* * The frame data is composed of the following areas and laid out as: * * ------------------------- * | alignment padding | * ------------------------- * | (f)xsave frame | * ------------------------- * | fsave header | * ------------------------- * | alignment padding | * ------------------------- * | siginfo + ucontext | * ------------------------- */ /* max_frame_size tells userspace the worst case signal stack size. */ static unsigned long __ro_after_init max_frame_size; static unsigned int __ro_after_init fpu_default_state_size; static int __init init_sigframe_size(void) { … } early_initcall(init_sigframe_size); unsigned long get_sigframe_size(void) { … } static int setup_rt_frame(struct ksignal *ksig, struct pt_regs *regs) { … } static void handle_signal(struct ksignal *ksig, struct pt_regs *regs) { … } static inline unsigned long get_nr_restart_syscall(const struct pt_regs *regs) { … } /* * Note that 'init' is a special process: it doesn't get signals it doesn't * want to handle. Thus you cannot kill init even with a SIGKILL even by * mistake. */ void arch_do_signal_or_restart(struct pt_regs *regs) { … } void signal_fault(struct pt_regs *regs, void __user *frame, char *where) { … } #ifdef CONFIG_DYNAMIC_SIGFRAME #ifdef CONFIG_STRICT_SIGALTSTACK_SIZE static bool strict_sigaltstack_size __ro_after_init = …; #else static bool strict_sigaltstack_size __ro_after_init = false; #endif static int __init strict_sas_size(char *arg) { … } __setup(…); /* * MINSIGSTKSZ is 2048 and can't be changed despite the fact that AVX512 * exceeds that size already. As such programs might never use the * sigaltstack they just continued to work. While always checking against * the real size would be correct, this might be considered a regression. * * Therefore avoid the sanity check, unless enforced by kernel * configuration or command line option. * * When dynamic FPU features are supported, the check is also enforced when * the task has permissions to use dynamic features. Tasks which have no * permission are checked against the size of the non-dynamic feature set * if strict checking is enabled. This avoids forcing all tasks on the * system to allocate large sigaltstacks even if they are never going * to use a dynamic feature. As this is serialized via sighand::siglock * any permission request for a dynamic feature either happened already * or will see the newly install sigaltstack size in the permission checks. */ bool sigaltstack_size_valid(size_t ss_size) { … } #endif /* CONFIG_DYNAMIC_SIGFRAME */
Codebase Browser
linux