block/ssh: Avoid segfault if inet_connect doesn't set errno.
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 -EIO (same as block/nbd.c and
block/sheepdog.c). 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 <rjones@redhat.com>
Reported-by: Jun Li
BZ: https://bugzilla.redhat.com/show_bug.cgi?id=1147343
Signed-off-by: Jeff Cody <jcody@redhat.com>
diff --git a/block/ssh.c b/block/ssh.c
index aebb18c..8d06739 100644
--- a/block/ssh.c
+++ b/block/ssh.c
@@ -563,7 +563,7 @@
/* Open the socket and connect. */
s->sock = inet_connect(s->hostport, errp);
if (s->sock < 0) {
- ret = -errno;
+ ret = -EIO;
goto err;
}
