[PATCH v5 4/6] x86/insn-eval: Make 0 a valid RIP for insn_get_effective_ip()
From: Joerg Roedel <joro@8bytes.org>
Date: 2021-06-14 13:53:54
Also in:
kvm, lkml, virtualization
Subsystem:
the rest, x86 architecture (32-bit and 64-bit) · Maintainers:
Linus Torvalds, Thomas Gleixner, Ingo Molnar, Borislav Petkov, Dave Hansen
From: Joerg Roedel <redacted> 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 <redacted> --- arch/x86/lib/insn-eval.c | 14 +++++++------- 1 file changed, 7 insertions(+), 7 deletions(-)
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index a67afd74232c..4eecb9c7c6a0 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);
--
2.31.1