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authorMasami Hiramatsu <masami.hiramatsu.pt@hitachi.com>2012-04-13 07:24:27 +0400
committerIngo Molnar <mingo@kernel.org>2012-04-16 10:56:11 +0400
commit6c7b8e82aab75a25581c4d446fc87f96634e9ef9 (patch)
tree088f31f88c85a64304c171eced7b4233cbece6a9 /arch/x86/lib
parent7ea6411f4ceb62e5e53170d59d10996dca20c599 (diff)
downloadlinux-6c7b8e82aab75a25581c4d446fc87f96634e9ef9.tar.xz
x86: Handle failures of parsing immediate operands in the instruction decoder
This can happen if the instruction is much longer than the maximum length, or if insn->opnd_bytes is manually changed. This patch also fixes warnings from -Wswitch-default flag. Reported-by: Prashanth Nageshappa <prashanth@linux.vnet.ibm.com> Signed-off-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@linux.vnet.ibm.com> Cc: Linux-mm <linux-mm@kvack.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Andi Kleen <andi@firstfloor.org> Cc: Christoph Hellwig <hch@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Arnaldo Carvalho de Melo <acme@infradead.org> Cc: Anton Arapov <anton@redhat.com> Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com> Cc: yrl.pp-manager.tt@hitachi.com Cc: Peter Zijlstra <peterz@infradead.org> Link: http://lkml.kernel.org/r/20120413032427.32577.42602.stgit@localhost.localdomain Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/lib')
-rw-r--r--arch/x86/lib/insn.c53
1 files changed, 36 insertions, 17 deletions
diff --git a/arch/x86/lib/insn.c b/arch/x86/lib/insn.c
index 25feb1ae71c5..b1e6c4b2e8eb 100644
--- a/arch/x86/lib/insn.c
+++ b/arch/x86/lib/insn.c
@@ -379,8 +379,8 @@ err_out:
return;
}
-/* Decode moffset16/32/64 */
-static void __get_moffset(struct insn *insn)
+/* Decode moffset16/32/64. Return 0 if failed */
+static int __get_moffset(struct insn *insn)
{
switch (insn->addr_bytes) {
case 2:
@@ -397,15 +397,19 @@ static void __get_moffset(struct insn *insn)
insn->moffset2.value = get_next(int, insn);
insn->moffset2.nbytes = 4;
break;
+ default: /* opnd_bytes must be modified manually */
+ goto err_out;
}
insn->moffset1.got = insn->moffset2.got = 1;
+ return 1;
+
err_out:
- return;
+ return 0;
}
-/* Decode imm v32(Iz) */
-static void __get_immv32(struct insn *insn)
+/* Decode imm v32(Iz). Return 0 if failed */
+static int __get_immv32(struct insn *insn)
{
switch (insn->opnd_bytes) {
case 2:
@@ -417,14 +421,18 @@ static void __get_immv32(struct insn *insn)
insn->immediate.value = get_next(int, insn);
insn->immediate.nbytes = 4;
break;
+ default: /* opnd_bytes must be modified manually */
+ goto err_out;
}
+ return 1;
+
err_out:
- return;
+ return 0;
}
-/* Decode imm v64(Iv/Ov) */
-static void __get_immv(struct insn *insn)
+/* Decode imm v64(Iv/Ov), Return 0 if failed */
+static int __get_immv(struct insn *insn)
{
switch (insn->opnd_bytes) {
case 2:
@@ -441,15 +449,18 @@ static void __get_immv(struct insn *insn)
insn->immediate2.value = get_next(int, insn);
insn->immediate2.nbytes = 4;
break;
+ default: /* opnd_bytes must be modified manually */
+ goto err_out;
}
insn->immediate1.got = insn->immediate2.got = 1;
+ return 1;
err_out:
- return;
+ return 0;
}
/* Decode ptr16:16/32(Ap) */
-static void __get_immptr(struct insn *insn)
+static int __get_immptr(struct insn *insn)
{
switch (insn->opnd_bytes) {
case 2:
@@ -462,14 +473,17 @@ static void __get_immptr(struct insn *insn)
break;
case 8:
/* ptr16:64 is not exist (no segment) */
- return;
+ return 0;
+ default: /* opnd_bytes must be modified manually */
+ goto err_out;
}
insn->immediate2.value = get_next(unsigned short, insn);
insn->immediate2.nbytes = 2;
insn->immediate1.got = insn->immediate2.got = 1;
+ return 1;
err_out:
- return;
+ return 0;
}
/**
@@ -489,7 +503,8 @@ void insn_get_immediate(struct insn *insn)
insn_get_displacement(insn);
if (inat_has_moffset(insn->attr)) {
- __get_moffset(insn);
+ if (!__get_moffset(insn))
+ goto err_out;
goto done;
}
@@ -517,16 +532,20 @@ void insn_get_immediate(struct insn *insn)
insn->immediate2.nbytes = 4;
break;
case INAT_IMM_PTR:
- __get_immptr(insn);
+ if (!__get_immptr(insn))
+ goto err_out;
break;
case INAT_IMM_VWORD32:
- __get_immv32(insn);
+ if (!__get_immv32(insn))
+ goto err_out;
break;
case INAT_IMM_VWORD:
- __get_immv(insn);
+ if (!__get_immv(insn))
+ goto err_out;
break;
default:
- break;
+ /* Here, insn must have an immediate, but failed */
+ goto err_out;
}
if (inat_has_second_immediate(insn->attr)) {
insn->immediate2.value = get_next(char, insn);