Commit 1ffa11ab authored Sep 13, 2013 by Heiko Carstens Committed by Martin Schwidefsky Oct 24, 2013

s390/kprobes: allow kprobes only on known instructions



Since we have an in-kernel disassembler we can make sure that
there won't be any kprobes set on random data.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

parent a882b3b0

arch/s390/include/asm/dis.h

+6 −0

Original line number	Original line	Diff line number	Diff line
	@@ -42,5 +42,11 @@ static inline int insn_length(unsigned char code)
	void show_code(struct pt_regs *regs);		void show_code(struct pt_regs *regs);
	void print_fn_code(unsigned char *code, unsigned long len);		void print_fn_code(unsigned char *code, unsigned long len);
	int insn_to_mnemonic(unsigned char instruction, char buf, unsigned int len);		int insn_to_mnemonic(unsigned char instruction, char buf, unsigned int len);
			struct s390_insn find_insn(unsigned char code);

			static inline int is_known_insn(unsigned char *code)
			{
			return !!find_insn(code);
			}

	#endif /* __ASM_S390_DIS_H__ */		#endif /* __ASM_S390_DIS_H__ */

arch/s390/kernel/dis.c

+1 −1

Original line number	Original line	Diff line number	Diff line
	@@ -1586,7 +1586,7 @@ static unsigned int extract_operand(unsigned char *code,
	return val;		return val;
	}		}

	static struct s390_insn find_insn(unsigned char code)		struct s390_insn find_insn(unsigned char code)
	{		{
	unsigned char opfrag = code[1];		unsigned char opfrag = code[1];
	unsigned char opmask;		unsigned char opmask;

arch/s390/kernel/kprobes.c

+2 −0

Original line number	Original line	Diff line number	Diff line
	@@ -60,6 +60,8 @@ struct kprobe_insn_cache kprobe_dmainsn_slots = {

	static int __kprobes is_prohibited_opcode(kprobe_opcode_t *insn)		static int __kprobes is_prohibited_opcode(kprobe_opcode_t *insn)
	{		{
			if (!is_known_insn((unsigned char *)insn))
			return -EINVAL;
	switch (insn[0] >> 8) {		switch (insn[0] >> 8) {
	case 0x0c: /* bassm */		case 0x0c: /* bassm */
	case 0x0b: /* bsm */		case 0x0b: /* bsm */