Commit f2df1563 authored by Joerg Roedel's avatar Joerg Roedel Committed by Borislav Petkov
Browse files

x86/insn-eval: Make 0 a valid RIP for insn_get_effective_ip() 



In theory, 0 is a valid value for the instruction pointer so don't use
it as the error return value from insn_get_effective_ip().

Signed-off-by: default avatarJoerg Roedel <jroedel@suse.de>
Signed-off-by: default avatarBorislav Petkov <bp@suse.de>
Link: https://lkml.kernel.org/r/20210614135327.9921-5-joro@8bytes.org
parent 4aca2d99

arch/x86/lib/insn-eval.c

+7 −7
Original line number Diff line number Diff line
@@ -1417,7 +1417,7 @@ void __user *insn_get_addr_ref(struct insn *insn, struct pt_regs *regs) 
	}

}



static unsigned long insn_get_effective_ip(struct pt_regs *regs)

static int insn_get_effective_ip(struct pt_regs *regs, unsigned long *ip)

{

	unsigned long seg_base = 0;
@@ -1430,10 +1430,12 @@ static unsigned long insn_get_effective_ip(struct pt_regs *regs) 
	if (!user_64bit_mode(regs)) {

		seg_base = insn_get_seg_base(regs, INAT_SEG_REG_CS);

		if (seg_base == -1L)

			return 0;

			return -EINVAL;

	}



	return seg_base + regs->ip;

	*ip = seg_base + regs->ip;



	return 0;

}



/**
@@ -1455,8 +1457,7 @@ int insn_fetch_from_user(struct pt_regs *regs, unsigned char buf[MAX_INSN_SIZE]) 
	unsigned long ip;

	int not_copied;



	ip = insn_get_effective_ip(regs);

	if (!ip)

	if (insn_get_effective_ip(regs, &ip))

		return 0;



	not_copied = copy_from_user(buf, (void __user *)ip, MAX_INSN_SIZE);
@@ -1484,8 +1485,7 @@ int insn_fetch_from_user_inatomic(struct pt_regs *regs, unsigned char buf[MAX_IN 
	unsigned long ip;

	int not_copied;



	ip = insn_get_effective_ip(regs);

	if (!ip)

	if (insn_get_effective_ip(regs, &ip))

		return 0;



	not_copied = __copy_from_user_inatomic(buf, (void __user *)ip, MAX_INSN_SIZE);