On Wed, Jul 22, 2015 at 02:07:22PM +0100, Richard W.M. Jones wrote:
> On some (but not all) systems:
>
> $ qemu-img create -f qcow2 overlay -b ssh://xen/
> Segmentation fault
>
> It turns out this happens when inet_connect returns -1 in the
> following code, but errno == 0.
>
> s->sock = inet_connect(s->hostport, errp);
> if (s->sock < 0) {
> ret = -errno;
> goto err;
> }
>
> In the test case above, no host called "xen" exists, so getaddrinfo fails.
>
> On Fedora 22, getaddrinfo happens to set errno = ENOENT (although it
> is *not* documented to do that), so it doesn't segfault.
>
> On RHEL 7, errno is not set by the failing getaddrinfo, so ret =
> -errno = 0, so the caller doesn't know there was an error and
> continues with a half-initialized BDRVSSHState struct, and everything
> goes south from there, eventually resulting in a segfault.
>
> Fix this by setting ret to -EINVAL. The real error is saved in the
> Error** errp struct, so it is printed correctly:
>
> $ ./qemu-img create -f qcow2 overlay -b ssh://xen/
> qemu-img: overlay: address resolution failed for xen:22: No address
> associated with hostname
>
> Signed-off-by: Richard W.M. Jones <rjo...@redhat.com>
> Reported-by: Jun Li
> BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1147343
> ---
> block/ssh.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/block/ssh.c b/block/ssh.c
> index aebb18c..8d4dc2a 100644
> --- a/block/ssh.c
> +++ b/block/ssh.c
> @@ -563,7 +563,7 @@ static int connect_to_ssh(BDRVSSHState *s, QDict *options,
> /* Open the socket and connect. */
> s->sock = inet_connect(s->hostport, errp);
> if (s->sock < 0) {
> - ret = -errno;
> + ret = -EINVAL;
> goto err;
There are a reasonable number of other uses of inet_connect() in QEMU,
so can't we fix inet_connect() itself to set EINVAL in the error case
instead of just fixing one caller.
Regards,
Daniel
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