[PATCH] kprobes: prevent possible race conditions i386 changes (3d97ae5b) · Commits · e / devices / android_kernel_fairphone_FP5

arch/i386/kernel/entry.S

+8 −5

Original line number	Diff line number	Diff line
		@@ -507,7 +507,7 @@ label: \
		pushl $__KERNEL_CS; \
		pushl $sysenter_past_esp

		ENTRY(debug)
		KPROBE_ENTRY(debug)
		cmpl $sysenter_entry,(%esp)
		jne debug_stack_correct
		FIX_STACK(12, debug_stack_correct, debug_esp_fix_insn)
		@@ -518,7 +518,7 @@ debug_stack_correct:
		movl %esp,%eax # pt_regs pointer
		call do_debug
		jmp ret_from_exception

		.previous .text
		/*
		* NMI is doubly nasty. It can happen _while_ we're handling
		* a debug fault, and the debug fault hasn't yet been able to
		@@ -591,13 +591,14 @@ nmi_16bit_stack:
		.long 1b,iret_exc
		.previous

		ENTRY(int3)
		KPROBE_ENTRY(int3)
		pushl $-1 # mark this as an int
		SAVE_ALL
		xorl %edx,%edx # zero error code
		movl %esp,%eax # pt_regs pointer
		call do_int3
		jmp ret_from_exception
		.previous .text

		ENTRY(overflow)
		pushl $0
		@@ -631,17 +632,19 @@ ENTRY(stack_segment)
		pushl $do_stack_segment
		jmp error_code

		ENTRY(general_protection)
		KPROBE_ENTRY(general_protection)
		pushl $do_general_protection
		jmp error_code
		.previous .text

		ENTRY(alignment_check)
		pushl $do_alignment_check
		jmp error_code

		ENTRY(page_fault)
		KPROBE_ENTRY(page_fault)
		pushl $do_page_fault
		jmp error_code
		.previous .text

		#ifdef CONFIG_X86_MCE
		ENTRY(machine_check)

arch/i386/kernel/kprobes.c

+15 −14

Original line number	Diff line number	Diff line
		@@ -62,32 +62,32 @@ static inline int is_IF_modifier(kprobe_opcode_t opcode)
		return 0;
		}

		int arch_prepare_kprobe(struct kprobe *p)
		int __kprobes arch_prepare_kprobe(struct kprobe *p)
		{
		return 0;
		}

		void arch_copy_kprobe(struct kprobe *p)
		void __kprobes arch_copy_kprobe(struct kprobe *p)
		{
		memcpy(p->ainsn.insn, p->addr, MAX_INSN_SIZE * sizeof(kprobe_opcode_t));
		p->opcode = *p->addr;
		}

		void arch_arm_kprobe(struct kprobe *p)
		void __kprobes arch_arm_kprobe(struct kprobe *p)
		{
		*p->addr = BREAKPOINT_INSTRUCTION;
		flush_icache_range((unsigned long) p->addr,
		(unsigned long) p->addr + sizeof(kprobe_opcode_t));
		}

		void arch_disarm_kprobe(struct kprobe *p)
		void __kprobes arch_disarm_kprobe(struct kprobe *p)
		{
		*p->addr = p->opcode;
		flush_icache_range((unsigned long) p->addr,
		(unsigned long) p->addr + sizeof(kprobe_opcode_t));
		}

		void arch_remove_kprobe(struct kprobe *p)
		void __kprobes arch_remove_kprobe(struct kprobe *p)
		{
		}

		@@ -127,7 +127,8 @@ static inline void prepare_singlestep(struct kprobe p, struct pt_regs regs)
		regs->eip = (unsigned long)&p->ainsn.insn;
		}

		void arch_prepare_kretprobe(struct kretprobe rp, struct pt_regs regs)
		void __kprobes arch_prepare_kretprobe(struct kretprobe *rp,
		struct pt_regs *regs)
		{
		unsigned long sara = (unsigned long )&regs->esp;
		struct kretprobe_instance *ri;
		@@ -150,7 +151,7 @@ void arch_prepare_kretprobe(struct kretprobe rp, struct pt_regs regs)
		* Interrupts are disabled on entry as trap3 is an interrupt gate and they
		* remain disabled thorough out this function.
		*/
		static int kprobe_handler(struct pt_regs *regs)
		static int __kprobes kprobe_handler(struct pt_regs *regs)
		{
		struct kprobe *p;
		int ret = 0;
		@@ -259,7 +260,7 @@ static int kprobe_handler(struct pt_regs *regs)
		/*
		* Called when we hit the probe point at kretprobe_trampoline
		*/
		int trampoline_probe_handler(struct kprobe p, struct pt_regs regs)
		int __kprobes trampoline_probe_handler(struct kprobe p, struct pt_regs regs)
		{
		struct kretprobe_instance *ri = NULL;
		struct hlist_head *head;
		@@ -338,7 +339,7 @@ int trampoline_probe_handler(struct kprobe p, struct pt_regs regs)
		* that is atop the stack is the address following the copied instruction.
		* We need to make it the address following the original instruction.
		*/
		static void resume_execution(struct kprobe p, struct pt_regs regs)
		static void __kprobes resume_execution(struct kprobe p, struct pt_regs regs)
		{
		unsigned long tos = (unsigned long )&regs->esp;
		unsigned long next_eip = 0;
		@@ -444,8 +445,8 @@ static inline int kprobe_fault_handler(struct pt_regs *regs, int trapnr)
		/*
		* Wrapper routine to for handling exceptions.
		*/
		int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
		void *data)
		int __kprobes kprobe_exceptions_notify(struct notifier_block *self,
		unsigned long val, void *data)
		{
		struct die_args args = (struct die_args )data;
		switch (val) {
		@@ -473,7 +474,7 @@ int kprobe_exceptions_notify(struct notifier_block *self, unsigned long val,
		return NOTIFY_DONE;
		}

		int setjmp_pre_handler(struct kprobe p, struct pt_regs regs)
		int __kprobes setjmp_pre_handler(struct kprobe p, struct pt_regs regs)
		{
		struct jprobe *jp = container_of(p, struct jprobe, kp);
		unsigned long addr;
		@@ -495,7 +496,7 @@ int setjmp_pre_handler(struct kprobe p, struct pt_regs regs)
		return 1;
		}

		void jprobe_return(void)
		void __kprobes jprobe_return(void)
		{
		preempt_enable_no_resched();
		asm volatile (" xchgl %%ebx,%%esp \n"
		@@ -506,7 +507,7 @@ void jprobe_return(void)
		(jprobe_saved_esp):"memory");
		}

		int longjmp_break_handler(struct kprobe p, struct pt_regs regs)
		int __kprobes longjmp_break_handler(struct kprobe p, struct pt_regs regs)
		{
		u8 addr = (u8 ) (regs->eip - 1);
		unsigned long stack_addr = (unsigned long)jprobe_saved_esp;

arch/i386/kernel/traps.c

+7 −5

Original line number	Diff line number	Diff line
		@@ -363,8 +363,9 @@ static inline void die_if_kernel(const char * str, struct pt_regs * regs, long e
		die(str, regs, err);
		}

		static void do_trap(int trapnr, int signr, char *str, int vm86,
		struct pt_regs * regs, long error_code, siginfo_t *info)
		static void __kprobes do_trap(int trapnr, int signr, char *str, int vm86,
		struct pt_regs * regs, long error_code,
		siginfo_t *info)
		{
		struct task_struct *tsk = current;
		tsk->thread.error_code = error_code;
		@@ -460,7 +461,8 @@ DO_ERROR(12, SIGBUS, "stack segment", stack_segment)
		DO_ERROR_INFO(17, SIGBUS, "alignment check", alignment_check, BUS_ADRALN, 0)
		DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0)

		fastcall void do_general_protection(struct pt_regs * regs, long error_code)
		fastcall void __kprobes do_general_protection(struct pt_regs * regs,
		long error_code)
		{
		int cpu = get_cpu();
		struct tss_struct *tss = &per_cpu(init_tss, cpu);
		@@ -676,7 +678,7 @@ void unset_nmi_callback(void)
		EXPORT_SYMBOL_GPL(unset_nmi_callback);

		#ifdef CONFIG_KPROBES
		fastcall void do_int3(struct pt_regs *regs, long error_code)
		fastcall void __kprobes do_int3(struct pt_regs *regs, long error_code)
		{
		if (notify_die(DIE_INT3, "int3", regs, error_code, 3, SIGTRAP)
		== NOTIFY_STOP)
		@@ -710,7 +712,7 @@ fastcall void do_int3(struct pt_regs *regs, long error_code)
		* find every occurrence of the TF bit that could be saved away even
		* by user code)
		*/
		fastcall void do_debug(struct pt_regs * regs, long error_code)
		fastcall void __kprobes do_debug(struct pt_regs * regs, long error_code)
		{
		unsigned int condition;
		struct task_struct *tsk = current;

arch/i386/kernel/vmlinux.lds.S

+1 −0

Original line number	Diff line number	Diff line
		@@ -22,6 +22,7 @@ SECTIONS
		*(.text)
		SCHED_TEXT
		LOCK_TEXT
		KPROBES_TEXT
		*(.fixup)
		*(.gnu.warning)
		} = 0x9090

arch/i386/mm/fault.c

+3 −1

Original line number	Diff line number	Diff line
		@@ -21,6 +21,7 @@
		#include <linux/vt_kern.h> /* For unblank_screen() */
		#include <linux/highmem.h>
		#include <linux/module.h>
		#include <linux/kprobes.h>

		#include <asm/system.h>
		#include <asm/uaccess.h>
		@@ -223,7 +224,8 @@ fastcall void do_invalid_op(struct pt_regs *, unsigned long);
		* bit 1 == 0 means read, 1 means write
		* bit 2 == 0 means kernel, 1 means user-mode
		*/
		fastcall void do_page_fault(struct pt_regs *regs, unsigned long error_code)
		fastcall void __kprobes do_page_fault(struct pt_regs *regs,
		unsigned long error_code)
		{
		struct task_struct *tsk;
		struct mm_struct *mm;