[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [RFC 6/6] OptsVisitor: don't try to flatten overlong intege
From: |
Laszlo Ersek |
Subject: |
[Qemu-devel] [RFC 6/6] OptsVisitor: don't try to flatten overlong integer ranges |
Date: |
Thu, 18 Jul 2013 15:59:24 +0200 |
Prevent mistyped command line options from incurring high memory and CPU
usage at startup. 64K elements in a range should be enough for everyone
(TM).
The OPTS_VISITOR_RANGE_MAX macro is public so that unit tests can
construct corner cases with it.
Signed-off-by: Laszlo Ersek <address@hidden>
---
include/qapi/opts-visitor.h | 6 ++++++
qapi/opts-visitor.c | 7 +++++--
2 files changed, 11 insertions(+), 2 deletions(-)
diff --git a/include/qapi/opts-visitor.h b/include/qapi/opts-visitor.h
index 5939eee..fd48c14 100644
--- a/include/qapi/opts-visitor.h
+++ b/include/qapi/opts-visitor.h
@@ -16,6 +16,12 @@
#include "qapi/visitor.h"
#include "qemu/option.h"
+/* Inclusive upper bound on the size of any flattened range. This is a safety
+ * (= anti-annoyance) measure; wrong ranges should not cause long startup
+ * delays nor exhaust virtual memory.
+ */
+#define OPTS_VISITOR_RANGE_MAX 65536
+
typedef struct OptsVisitor OptsVisitor;
/* Contrarily to qemu-option.c::parse_option_number(), OptsVisitor's "int"
diff --git a/qapi/opts-visitor.c b/qapi/opts-visitor.c
index 4413400..f6b089f 100644
--- a/qapi/opts-visitor.c
+++ b/qapi/opts-visitor.c
@@ -361,7 +361,9 @@ opts_type_int(Visitor *v, int64_t *obj, const char *name,
Error **errp)
str = endptr + 1;
val2 = strtoll(str, &endptr, 0);
if (errno == 0 && endptr > str && *endptr == '\0' &&
- INT64_MIN <= val2 && val2 <= INT64_MAX && val <= val2) {
+ INT64_MIN <= val2 && val2 <= INT64_MAX && val <= val2 &&
+ (val > INT64_MAX - OPTS_VISITOR_RANGE_MAX ||
+ val2 < val + OPTS_VISITOR_RANGE_MAX)) {
ov->range_next.s = val;
ov->range_limit.s = val2;
ov->list_mode = LM_SIGNED_INTERVAL;
@@ -412,7 +414,8 @@ opts_type_uint64(Visitor *v, uint64_t *obj, const char
*name, Error **errp)
str = endptr + 1;
if (parse_uint_full(str, &val2, 0) == 0 &&
- val2 <= UINT64_MAX && val <= val2) {
+ val2 <= UINT64_MAX && val <= val2 &&
+ val2 - val < OPTS_VISITOR_RANGE_MAX) {
ov->range_next.u = val;
ov->range_limit.u = val2;
ov->list_mode = LM_UNSIGNED_INTERVAL;
--
1.7.1
- Re: [Qemu-devel] [RFC 1/6] OptsVisitor: introduce basic list modes, (continued)
[Qemu-devel] [RFC 4/6] OptsVisitor: rebase opts_type_uint64() to parse_uint_full(), Laszlo Ersek, 2013/07/18
[Qemu-devel] [RFC 3/6] OptsVisitor: opts_type_int(): recognize intervals when LM_IN_PROGRESS, Laszlo Ersek, 2013/07/18
[Qemu-devel] [RFC 5/6] OptsVisitor: opts_type_uint64(): recognize intervals when LM_IN_PROGRESS, Laszlo Ersek, 2013/07/18
[Qemu-devel] [RFC 6/6] OptsVisitor: don't try to flatten overlong integer ranges,
Laszlo Ersek <=