lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Date:	Mon, 01 Jun 2009 20:37:37 -0400
From:	Masami Hiramatsu <mhiramat@...hat.com>
To:	Ingo Molnar <mingo@...e.hu>, Steven Rostedt <rostedt@...dmis.org>,
	lkml <linux-kernel@...r.kernel.org>
Cc:	systemtap <systemtap@...rces.redhat.com>,
	kvm <kvm@...r.kernel.org>,
	DLE <dle-develop@...ts.sourceforge.net>,
	Masami Hiramatsu <mhiramat@...hat.com>,
	Ananth N Mavinakayanahalli <ananth@...ibm.com>,
	Jim Keniston <jkenisto@...ibm.com>, Ingo Molnar <mingo@...e.hu>
Subject: [PATCH -tip v9 4/7] kprobes: cleanup fix_riprel() using insn decoder
	on x86

Cleanup fix_riprel() in arch/x86/kernel/kprobes.c by using x86 instruction
decoder.

Signed-off-by: Masami Hiramatsu <mhiramat@...hat.com>
Cc: Ananth N Mavinakayanahalli <ananth@...ibm.com>
Cc: Jim Keniston <jkenisto@...ibm.com>
Cc: Ingo Molnar <mingo@...e.hu>
---

 arch/x86/kernel/kprobes.c |  128 ++++++++-------------------------------------
 1 files changed, 23 insertions(+), 105 deletions(-)

diff --git a/arch/x86/kernel/kprobes.c b/arch/x86/kernel/kprobes.c
index 41d524f..ebac470 100644
--- a/arch/x86/kernel/kprobes.c
+++ b/arch/x86/kernel/kprobes.c
@@ -108,50 +108,6 @@ static const u32 twobyte_is_boostable[256 / 32] = {
 	/*      -----------------------------------------------         */
 	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
 };
-static const u32 onebyte_has_modrm[256 / 32] = {
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-	/*      -----------------------------------------------         */
-	W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 00 */
-	W(0x10, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 10 */
-	W(0x20, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) | /* 20 */
-	W(0x30, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0) , /* 30 */
-	W(0x40, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 40 */
-	W(0x50, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 50 */
-	W(0x60, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 1, 0, 0, 0, 0) | /* 60 */
-	W(0x70, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 70 */
-	W(0x80, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 80 */
-	W(0x90, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 90 */
-	W(0xa0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* a0 */
-	W(0xb0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* b0 */
-	W(0xc0, 1, 1, 0, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* c0 */
-	W(0xd0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 1, 1, 1, 1, 1, 1) , /* d0 */
-	W(0xe0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* e0 */
-	W(0xf0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1)   /* f0 */
-	/*      -----------------------------------------------         */
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-};
-static const u32 twobyte_has_modrm[256 / 32] = {
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-	/*      -----------------------------------------------         */
-	W(0x00, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 0, 1) | /* 0f */
-	W(0x10, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0) , /* 1f */
-	W(0x20, 1, 1, 1, 1, 1, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1) | /* 2f */
-	W(0x30, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) , /* 3f */
-	W(0x40, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 4f */
-	W(0x50, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 5f */
-	W(0x60, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* 6f */
-	W(0x70, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 1, 1, 1, 1) , /* 7f */
-	W(0x80, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0) | /* 8f */
-	W(0x90, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* 9f */
-	W(0xa0, 0, 0, 0, 1, 1, 1, 1, 1, 0, 0, 0, 1, 1, 1, 1, 1) | /* af */
-	W(0xb0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 1, 1, 1, 1) , /* bf */
-	W(0xc0, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0) | /* cf */
-	W(0xd0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) , /* df */
-	W(0xe0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1) | /* ef */
-	W(0xf0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0)   /* ff */
-	/*      -----------------------------------------------         */
-	/*      0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f          */
-};
 #undef W
 
 struct kretprobe_blackpoint kretprobe_blacklist[] = {
@@ -344,68 +300,30 @@ static int __kprobes is_IF_modifier(kprobe_opcode_t *insn)
 static void __kprobes fix_riprel(struct kprobe *p)
 {
 #ifdef CONFIG_X86_64
-	u8 *insn = p->ainsn.insn;
-	s64 disp;
-	int need_modrm;
-
-	/* Skip legacy instruction prefixes.  */
-	while (1) {
-		switch (*insn) {
-		case 0x66:
-		case 0x67:
-		case 0x2e:
-		case 0x3e:
-		case 0x26:
-		case 0x64:
-		case 0x65:
-		case 0x36:
-		case 0xf0:
-		case 0xf3:
-		case 0xf2:
-			++insn;
-			continue;
-		}
-		break;
-	}
+	struct insn insn;
+	kernel_insn_init(&insn, p->ainsn.insn);
 
-	/* Skip REX instruction prefix.  */
-	if (is_REX_prefix(insn))
-		++insn;
-
-	if (*insn == 0x0f) {
-		/* Two-byte opcode.  */
-		++insn;
-		need_modrm = test_bit(*insn,
-				      (unsigned long *)twobyte_has_modrm);
-	} else
-		/* One-byte opcode.  */
-		need_modrm = test_bit(*insn,
-				      (unsigned long *)onebyte_has_modrm);
-
-	if (need_modrm) {
-		u8 modrm = *++insn;
-		if ((modrm & 0xc7) == 0x05) {
-			/* %rip+disp32 addressing mode */
-			/* Displacement follows ModRM byte.  */
-			++insn;
-			/*
-			 * The copied instruction uses the %rip-relative
-			 * addressing mode.  Adjust the displacement for the
-			 * difference between the original location of this
-			 * instruction and the location of the copy that will
-			 * actually be run.  The tricky bit here is making sure
-			 * that the sign extension happens correctly in this
-			 * calculation, since we need a signed 32-bit result to
-			 * be sign-extended to 64 bits when it's added to the
-			 * %rip value and yield the same 64-bit result that the
-			 * sign-extension of the original signed 32-bit
-			 * displacement would have given.
-			 */
-			disp = (u8 *) p->addr + *((s32 *) insn) -
-			       (u8 *) p->ainsn.insn;
-			BUG_ON((s64) (s32) disp != disp); /* Sanity check.  */
-			*(s32 *)insn = (s32) disp;
-		}
+	if (insn_rip_relative(&insn)) {
+		s64 newdisp;
+		u8 *disp;
+		insn_get_displacement(&insn);
+		/*
+		 * The copied instruction uses the %rip-relative addressing
+		 * mode.  Adjust the displacement for the difference between
+		 * the original location of this instruction and the location
+		 * of the copy that will actually be run.  The tricky bit here
+		 * is making sure that the sign extension happens correctly in
+		 * this calculation, since we need a signed 32-bit result to
+		 * be sign-extended to 64 bits when it's added to the %rip
+		 * value and yield the same 64-bit result that the sign-
+		 * extension of the original signed 32-bit displacement would
+		 * have given.
+		 */
+		newdisp = (u8 *) p->addr + (s64) insn.displacement.value -
+			  (u8 *) p->ainsn.insn;
+		BUG_ON((s64) (s32) newdisp != newdisp); /* Sanity check.  */
+		disp = (u8 *) p->ainsn.insn + INSN_DISPLACEMENT_OFFS(&insn);
+		*(s32 *) disp = (s32) newdisp;
 	}
 #endif
 }


-- 
Masami Hiramatsu

Software Engineer
Hitachi Computer Products (America), Inc.
Software Solutions Division

e-mail: mhiramat@...hat.com
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Powered by blists - more mailing lists