On Mon, Oct 06, 2014 at 04:38:59PM +0200, Laszlo Ersek wrote:
> On 10/06/14 16:32, Richard W.M. Jones wrote:
> > qemu_opt_get_number returns a uint64_t, and curl_easy_setopt expects a
> > long (not an int).
> >
> > Store the timeout (which is a positive number of seconds) as a
> > uint64_t. Check that the number given by the user is reasonable.
> > Cast it to long before calling curl_easy_setopt.
> >
> > Example error message after this change has been applied:
> >
> > $ ./qemu-img create -f qcow2 /tmp/test.qcow2 \
> > -b 'json: { "file.driver":"https",
> > "file.url":"https://foo/bar";,
> > "file.timeout":-1 }'
> > qemu-img: /tmp/test.qcow2: Could not open 'json: { "file.driver":"https",
> > "file.url":"https://foo/bar";, "file.timeout":-1 }': timeout parameter is
> > too large or negative: Invalid argument
> >
> > Signed-off-by: Richard W.M. Jones <rjo...@redhat.com>
> > ---
> > block/curl.c | 8 ++++++--
> > 1 file changed, 6 insertions(+), 2 deletions(-)
> >
> > diff --git a/block/curl.c b/block/curl.c
> > index 225407c..5233ff6 100644
> > --- a/block/curl.c
> > +++ b/block/curl.c
> > @@ -112,7 +112,7 @@ typedef struct BDRVCURLState {
> > char *url;
> > size_t readahead_size;
> > bool sslverify;
> > - int timeout;
> > + uint64_t timeout;
> > char *cookie;
> > bool accept_range;
> > AioContext *aio_context;
> > @@ -390,7 +390,7 @@ static CURLState *curl_init_state(BlockDriverState *bs,
> > BDRVCURLState *s)
> > if (s->cookie) {
> > curl_easy_setopt(state->curl, CURLOPT_COOKIE, s->cookie);
> > }
> > - curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, s->timeout);
> > + curl_easy_setopt(state->curl, CURLOPT_TIMEOUT, (long)s->timeout);
> > curl_easy_setopt(state->curl, CURLOPT_WRITEFUNCTION,
> > (void *)curl_read_cb);
> > curl_easy_setopt(state->curl, CURLOPT_WRITEDATA, (void *)state);
> > @@ -546,6 +546,10 @@ static int curl_open(BlockDriverState *bs, QDict
> > *options, int flags,
> >
> > s->timeout = qemu_opt_get_number(opts, CURL_BLOCK_OPT_TIMEOUT,
> > CURL_TIMEOUT_DEFAULT);
> > + if (s->timeout > 100000) {
> > + error_setg(errp, "timeout parameter is too large or negative");
> > + goto out_noclean;
> > + }
> >
> > s->sslverify = qemu_opt_get_bool(opts, CURL_BLOCK_OPT_SSLVERIFY, true);
> >
> >
>
> Since we're validating s->timeout -- is a zero value okay?
Yes it's OK. It means wait forever:
CURLOPT_TIMEOUT
Pass a long as parameter containing the maximum time in seconds
that you allow the libcurl transfer operation to take. Normally,
name lookups can take a considerable time and limiting opera‐
tions to less than a few minutes risk aborting perfectly normal
operations. This option will cause curl to use the SIGALRM to
enable time-outing system calls.
In unix-like systems, this might cause signals to be used unless
CURLOPT_NOSIGNAL is set.
Default timeout is 0 (zero) which means it never times out.
Rich.
--
Richard Jones, Virtualization Group, Red Hat http://people.redhat.com/~rjones
Read my programming and virtualization blog: http://rwmj.wordpress.com
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