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Re: [Qemu-devel] [PATCH] block/curl: Improve type safety of s->timeout.
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [PATCH] block/curl: Improve type safety of s->timeout. |
Date: |
Mon, 06 Oct 2014 16:38:59 +0200 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.2 |
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 <address@hidden>
> ---
> 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?
Thanks
Laszlo