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Message-Id: <20210608095439.12668-6-joro@8bytes.org>
Date: Tue, 8 Jun 2021 11:54:37 +0200
From: Joerg Roedel <joro@...tes.org>
To: x86@...nel.org
Cc: Joerg Roedel <joro@...tes.org>, Joerg Roedel <jroedel@...e.de>,
hpa@...or.com, Andy Lutomirski <luto@...nel.org>,
Dave Hansen <dave.hansen@...ux.intel.com>,
Peter Zijlstra <peterz@...radead.org>,
Jiri Slaby <jslaby@...e.cz>,
Dan Williams <dan.j.williams@...el.com>,
Tom Lendacky <thomas.lendacky@....com>,
Juergen Gross <jgross@...e.com>,
Kees Cook <keescook@...omium.org>,
David Rientjes <rientjes@...gle.com>,
Cfir Cohen <cfir@...gle.com>,
Erdem Aktas <erdemaktas@...gle.com>,
Masami Hiramatsu <mhiramat@...nel.org>,
Mike Stunes <mstunes@...are.com>,
Sean Christopherson <seanjc@...gle.com>,
Martin Radev <martin.b.radev@...il.com>,
Arvind Sankar <nivedita@...m.mit.edu>,
linux-coco@...ts.linux.dev, linux-kernel@...r.kernel.org,
kvm@...r.kernel.org, virtualization@...ts.linux-foundation.org
Subject: [PATCH v3 5/7] x86/insn-eval: Make 0 a valid RIP for insn_get_effective_ip()
From: Joerg Roedel <jroedel@...e.de>
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 <jroedel@...e.de>
---
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
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