diff options
| author | Daniel P. Berrange <berrange@redhat.com> | 2015-12-21 11:58:51 +0000 |
|---|---|---|
| committer | Daniel P. Berrange <berrange@redhat.com> | 2015-12-23 10:53:03 +0000 |
| commit | 7b3c618ad0cd0154993b5b5dbd34e0010960585a (patch) | |
| tree | b6889811b57451057c2cceb1d3a94e969c7230b2 /io | |
| parent | bead59946a8b54398f4ba3c9c8ecd15eeac78c53 (diff) | |
io: fix stack allocation when sending of file descriptors
When sending file descriptors over a socket, we have to
allocate a data buffer to hold the FDs in the scmsghdr.
Unfortunately we allocated the buffer on the stack inside
an if () {} block, but called sendmsg() outside the block.
So the stack bytes holding the FDs were liable to be
overwritten with other data. By luck this was not a problem
when sending 1 FD, but if sending 2 or more then it would
fail.
The fix is to simply move the variables outside the nested
'if' block. To keep valgrind quiet we also zero-initialize
the 'control' buffer.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Diffstat (limited to 'io')
| -rw-r--r-- | io/channel-socket.c | 7 |
1 files changed, 3 insertions, 4 deletions
diff --git a/io/channel-socket.c b/io/channel-socket.c index eed2ff5bcf..10a5b3136e 100644 --- a/io/channel-socket.c +++ b/io/channel-socket.c @@ -493,15 +493,14 @@ static ssize_t qio_channel_socket_writev(QIOChannel *ioc, QIOChannelSocket *sioc = QIO_CHANNEL_SOCKET(ioc); ssize_t ret; struct msghdr msg = { NULL, }; + char control[CMSG_SPACE(sizeof(int) * SOCKET_MAX_FDS)] = { 0 }; + size_t fdsize = sizeof(int) * nfds; + struct cmsghdr *cmsg; msg.msg_iov = (struct iovec *)iov; msg.msg_iovlen = niov; if (nfds) { - char control[CMSG_SPACE(sizeof(int) * SOCKET_MAX_FDS)]; - size_t fdsize = sizeof(int) * nfds; - struct cmsghdr *cmsg; - if (nfds > SOCKET_MAX_FDS) { error_setg_errno(errp, -EINVAL, "Only %d FDs can be sent, got %zu", |