[Qemu-devel] [PATCH v2 1/1] block/gluster: improve defense over string to int conversion

[Prasanna Kumar Kalever <prasanna.kalever@redhat.com>]

using atoi() for converting string to int may be error prone in case if
string supplied in the argument is not a fold of numerical number,

This is not a bug because in the existing code,

static QemuOptsList runtime_tcp_opts = {
    .name = "gluster_tcp",
    .head = QTAILQ_HEAD_INITIALIZER(runtime_tcp_opts.head),
    .desc = {
        ...
        {
            .name = GLUSTER_OPT_PORT,
            .type = QEMU_OPT_NUMBER,
            .help = "port number ...",
        },
...
};

port type is QEMU_OPT_NUMBER, before we actually reaches atoi() port is already
defended by parse_option_number()

However It is a good practice to use function like parse_uint_full()
over atoi() to keep port self defended

Note: As now the port string to int conversion has its defence code set,
and also we understand that port argument is actually a string type,
in the follow up patch let's move port type from QEMU_OPT_NUMBER to
QEMU_OPT_STRING

Signed-off-by: Prasanna Kumar Kalever <prasanna.kalever@redhat.com>
---
v1: Initial patch
v2: Address comments on v1 given by Markus
---
 block/gluster.c | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/block/gluster.c b/block/gluster.c
index 01b479f..edde1ad 100644
--- a/block/gluster.c
+++ b/block/gluster.c
@@ -14,6 +14,7 @@
 #include "qapi/qmp/qerror.h"
 #include "qemu/uri.h"
 #include "qemu/error-report.h"
+#include "qemu/cutils.h"
 
 #define GLUSTER_OPT_FILENAME        "filename"
 #define GLUSTER_OPT_VOLUME          "volume"
@@ -318,6 +319,7 @@ static struct glfs *qemu_gluster_glfs_init(BlockdevOptionsGluster *gconf,
     int ret;
     int old_errno;
     GlusterServerList *server;
+    unsigned long long port;
 
     glfs = glfs_new(gconf->volume);
     if (!glfs) {
@@ -330,10 +332,17 @@ static struct glfs *qemu_gluster_glfs_init(BlockdevOptionsGluster *gconf,
                                    GlusterTransport_lookup[server->value->type],
                                    server->value->u.q_unix.path, 0);
         } else {
+            if ((parse_uint_full(server->value->u.tcp.port, &port, 10) < 0) ||
+                (port > 65535)) {
+                error_setg(errp, "'%s' is not a valid port number",
+                           server->value->u.tcp.port);
+                errno = EINVAL;
+                goto out;
+            }
             ret = glfs_set_volfile_server(glfs,
                                    GlusterTransport_lookup[server->value->type],
                                    server->value->u.tcp.host,
-                                   atoi(server->value->u.tcp.port));
+                                   (int)port);
         }
 
         if (ret < 0) {
-- 
2.7.4