From: Joerg Roedel Date: Wed, 19 May 2021 13:52:49 +0000 (+0200) Subject: x86/insn-eval: Make 0 a valid RIP for insn_get_effective_ip() X-Git-Tag: v5.14-rc1~183^2~6 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=f2df15639e44d23bf82a86a03092472c7278cd39;p=thirdparty%2Flinux.git 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: Joerg Roedel Signed-off-by: Borislav Petkov Link: https://lkml.kernel.org/r/20210614135327.9921-5-joro@8bytes.org --- diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c index a67afd74232c6..4eecb9c7c6a05 100644 --- a/arch/x86/lib/insn-eval.c +++ b/arch/x86/lib/insn-eval.c @@ -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);