[Qemu-devel] [PATCH RFC v9 5/7] qemu-iotests: s390x: fix test 049

[Bo Tu <tubo@linux.vnet.ibm.com>]

when creating an image qemu-img enable us specifying the size of the
image using -o size=xx options. But when we specify an invalid size
such as a negtive size then different platform gives different result.

parse_option_size() function in util/qemu-option.c will be called to
parse the size, a cast was called in the function to cast the input
(saved as a double in the function) size to an unsigned int64 value,
when the input is a negtive value or exceeds the maximum of uint64, then
the result is undefined.

Language spec 6.3.1.4 Real floating and integers:
the result of this assignment/cast is undefined if the float is not
in the open interval (-1, U<type>_MAX+1).

Signed-off-by: Bo Tu <tubo@linux.vnet.ibm.com>
---
 tests/qemu-iotests/049.out | 10 ++++------
 util/qemu-option.c         |  5 +++++
 2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/tests/qemu-iotests/049.out b/tests/qemu-iotests/049.out
index 9f93666..b8790f9 100644
--- a/tests/qemu-iotests/049.out
+++ b/tests/qemu-iotests/049.out
@@ -95,17 +95,15 @@ qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- -1024
 qemu-img: Image size must be less than 8 EiB!
 
 qemu-img create -f qcow2 -o size=-1024 TEST_DIR/t.qcow2
-qemu-img: qcow2 doesn't support shrinking images yet
-qemu-img: TEST_DIR/t.qcow2: Could not resize image: Operation not supported
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
+qemu-img: Parameter 'size' expects a non-negative number below 2^64
+qemu-img: TEST_DIR/t.qcow2: Invalid options for file format 'qcow2'
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- -1k
 qemu-img: Image size must be less than 8 EiB!
 
 qemu-img create -f qcow2 -o size=-1k TEST_DIR/t.qcow2
-qemu-img: qcow2 doesn't support shrinking images yet
-qemu-img: TEST_DIR/t.qcow2: Could not resize image: Operation not supported
-Formatting 'TEST_DIR/t.qcow2', fmt=qcow2 size=-1024 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
+qemu-img: Parameter 'size' expects a non-negative number below 2^64
+qemu-img: TEST_DIR/t.qcow2: Invalid options for file format 'qcow2'
 
 qemu-img create -f qcow2 TEST_DIR/t.qcow2 -- 1kilobyte
 qemu-img: Invalid image size specified! You may use k, M, G, T, P or E suffixes for
diff --git a/util/qemu-option.c b/util/qemu-option.c
index fda4e5f..57b20c5 100644
--- a/util/qemu-option.c
+++ b/util/qemu-option.c
@@ -179,6 +179,11 @@ void parse_option_size(const char *name, const char *value,
 
     if (value != NULL) {
         sizef = strtod(value, &postfix);
+        if (sizef < 0 || sizef > UINT64_MAX) {
+            error_set(errp, QERR_INVALID_PARAMETER_VALUE, name, \
+                            "a non-negative number below 2^64");
+            return;
+        }
         switch (*postfix) {
         case 'T':
             sizef *= 1024;
-- 
2.3.0