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From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@amacapital.net>,
	Masami Hiramatsu <mhiramat@kernel.org>
Cc: X86 ML <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH v1 04/19] x86/insn-eval: Handle return values from the decoder
Date: Wed, 23 Dec 2020 18:42:18 +0100	[thread overview]
Message-ID: <20201223174233.28638-5-bp@alien8.de> (raw)
In-Reply-To: <20201223174233.28638-1-bp@alien8.de>

From: Borislav Petkov <bp@suse.de>

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@suse.de>
---
 arch/x86/lib/insn-eval.c | 19 +++++++++++++------
 1 file changed, 13 insertions(+), 6 deletions(-)

diff --git a/arch/x86/lib/insn-eval.c b/arch/x86/lib/insn-eval.c
index 265d23a0c334..7e49aaf5454c 100644
--- a/arch/x86/lib/insn-eval.c
+++ b/arch/x86/lib/insn-eval.c
@@ -1106,18 +1106,21 @@ 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;
@@ -1125,7 +1128,9 @@ 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;
@@ -1194,8 +1199,8 @@ 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;
@@ -1491,7 +1496,9 @@ bool insn_decode_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;
 
-- 
2.29.2


  parent reply	other threads:[~2020-12-23 17:43 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-23 17:42 [PATCH v1 00/19] x86/insn: Add an insn_decode() API Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 01/19] x86/insn: Rename insn_decode() to insn_decode_regs() Borislav Petkov
2020-12-28 17:16   ` Sean Christopherson
2020-12-29 19:36     ` Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 02/19] x86/insn: Add @buf_len param to insn_init() kernel-doc comment Borislav Petkov
2020-12-28  1:44   ` Masami Hiramatsu
2020-12-23 17:42 ` [PATCH v1 03/19] x86/insn: Add an insn_decode() API Borislav Petkov
2020-12-28  1:15   ` Masami Hiramatsu
2020-12-29 20:06     ` Borislav Petkov
2020-12-30  9:00       ` Masami Hiramatsu
2020-12-30  9:28         ` Borislav Petkov
2021-01-06  5:21           ` Masami Hiramatsu
2021-01-08 18:59             ` Borislav Petkov
2021-01-12 11:34               ` Masami Hiramatsu
2021-01-13 18:06                 ` Borislav Petkov
2020-12-23 17:42 ` Borislav Petkov [this message]
2020-12-28 18:51   ` [PATCH v1 04/19] x86/insn-eval: Handle return values from the decoder Sean Christopherson
2020-12-28 19:06     ` Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 05/19] x86/boot/compressed/sev-es: Convert to insn_decode() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 06/19] perf/x86/intel/ds: Check insn_get_length() retval Borislav Petkov
2021-01-04 13:19   ` Peter Zijlstra
2021-01-19 10:40     ` Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 07/19] perf/x86/intel/ds: Check return values of insn decoder functions Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 08/19] x86/alternative: Use insn_decode() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 09/19] x86/mce: Convert to insn_decode() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 10/19] x86/kprobes: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 11/19] x86/sev-es: " Borislav Petkov
2020-12-25 10:50   ` kernel test robot
2020-12-25 12:33     ` Borislav Petkov
2020-12-28 19:15       ` Sean Christopherson
2021-01-21 16:58         ` Borislav Petkov
2021-01-21 22:35           ` Sean Christopherson
2020-12-23 17:42 ` [PATCH v1 12/19] x86/traps: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 13/19] x86/uprobes: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 14/19] x86/tools/insn_decoder_test: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 15/19] tools/objtool: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 16/19] x86/tools/insn_sanity: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 17/19] tools/perf: " Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 18/19] x86/insn: Remove kernel_insn_init() Borislav Petkov
2020-12-23 17:42 ` [PATCH v1 19/19] x86/insn: Make insn_complete() static Borislav Petkov
2020-12-27 15:26 ` [PATCH v1 00/19] x86/insn: Add an insn_decode() API Tom Lendacky
2021-02-03 12:00   ` Borislav Petkov

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