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Message-ID: <161582326863.398.12655944025614758313.tip-bot2@tip-bot2>
Date: Mon, 15 Mar 2021 15:47:48 -0000
From: "tip-bot2 for Borislav Petkov" <tip-bot2@...utronix.de>
To: linux-tip-commits@...r.kernel.org
Cc: Borislav Petkov <bp@...e.de>, x86@...nel.org,
linux-kernel@...r.kernel.org
Subject: [tip: x86/core] x86/insn-eval: Handle return values from the decoder
The following commit has been merged into the x86/core branch of tip:
Commit-ID: 6e8c83d2a3afbfd5ee019ec720b75a42df515caa
Gitweb: https://git.kernel.org/tip/6e8c83d2a3afbfd5ee019ec720b75a42df515caa
Author: Borislav Petkov <bp@...e.de>
AuthorDate: Thu, 19 Nov 2020 19:20:18 +01:00
Committer: Borislav Petkov <bp@...e.de>
CommitterDate: Mon, 15 Mar 2021 11:12:15 +01:00
x86/insn-eval: Handle return values from the decoder
Now that the different instruction-inspecting functions return a value,
test that and return early from callers if error has been encountered.
While at it, do not call insn_get_modrm() when calling
insn_get_displacement() because latter will make sure to call
insn_get_modrm() if ModRM hasn't been parsed yet.
Signed-off-by: Borislav Petkov <bp@...e.de>
Link: https://lkml.kernel.org/r/20210304174237.31945-6-bp@alien8.de
---
arch/x86/lib/insn-eval.c | 34 +++++++++++++++++++++-------------
1 file changed, 21 insertions(+), 13 deletions(-)
diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 422a592..321a157 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -924,10 +924,11 @@ static int get_seg_base_limit(struct insn *insn, struct pt_regs *regs,
static int get_eff_addr_reg(struct insn *insn, struct pt_regs *regs,
int *regoff, long *eff_addr)
{
- insn_get_modrm(insn);
+ int ret;
- if (!insn->modrm.nbytes)
- return -EINVAL;
+ ret = insn_get_modrm(insn);
+ if (ret)
+ return ret;
if (X86_MODRM_MOD(insn->modrm.value) != 3)
return -EINVAL;
@@ -973,14 +974,14 @@ static int get_eff_addr_modrm(struct insn *insn, struct pt_regs *regs,
int *regoff, long *eff_addr)
{
long tmp;
+ int ret;
if (insn->addr_bytes != 8 && insn->addr_bytes != 4)
return -EINVAL;
- insn_get_modrm(insn);
-
- if (!insn->modrm.nbytes)
- return -EINVAL;
+ ret = insn_get_modrm(insn);
+ if (ret)
+ return ret;
if (X86_MODRM_MOD(insn->modrm.value) > 2)
return -EINVAL;
@@ -1102,18 +1103,21 @@ static int get_eff_addr_modrm_16(struct insn *insn, struct pt_regs *regs,
* @base_offset will have a register, as an offset from the base of pt_regs,
* that can be used to resolve the associated segment.
*
- * -EINVAL on error.
+ * Negative value on error.
*/
static int get_eff_addr_sib(struct insn *insn, struct pt_regs *regs,
int *base_offset, long *eff_addr)
{
long base, indx;
int indx_offset;
+ int ret;
if (insn->addr_bytes != 8 && insn->addr_bytes != 4)
return -EINVAL;
- insn_get_modrm(insn);
+ ret = insn_get_modrm(insn);
+ if (ret)
+ return ret;
if (!insn->modrm.nbytes)
return -EINVAL;
@@ -1121,7 +1125,9 @@ static int get_eff_addr_sib(struct insn *insn, struct pt_regs *regs,
if (X86_MODRM_MOD(insn->modrm.value) > 2)
return -EINVAL;
- insn_get_sib(insn);
+ ret = insn_get_sib(insn);
+ if (ret)
+ return ret;
if (!insn->sib.nbytes)
return -EINVAL;
@@ -1190,8 +1196,8 @@ static void __user *get_addr_ref_16(struct insn *insn, struct pt_regs *regs)
short eff_addr;
long tmp;
- insn_get_modrm(insn);
- insn_get_displacement(insn);
+ if (insn_get_displacement(insn))
+ goto out;
if (insn->addr_bytes != 2)
goto out;
@@ -1525,7 +1531,9 @@ bool insn_decode_from_regs(struct insn *insn, struct pt_regs *regs,
insn->addr_bytes = INSN_CODE_SEG_ADDR_SZ(seg_defs);
insn->opnd_bytes = INSN_CODE_SEG_OPND_SZ(seg_defs);
- insn_get_length(insn);
+ if (insn_get_length(insn))
+ return false;
+
if (buf_size < insn->length)
return false;
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