From bbdd2ad0814ea0911076419ea21b7957505cf1cc Mon Sep 17 00:00:00 2001 From: David Gibson Date: Mon, 10 Sep 2012 12:30:56 +1000 Subject: qemu-char: BUGFIX, don't call FD_ISSET with negative fd tcp_chr_connect(), unlike for example udp_chr_update_read_handler() does not check if the fd it is using is valid (>= 0) before passing it to qemu_set_fd_handler2(). If using e.g. a TCP serial port, which is not initially connected, this can result in -1 being passed to FD_ISSET, which has undefined behaviour. On x86 it seems to harmlessly return 0, but on PowerPC, it causes a fortify buffer overflow error to be thrown. This patch fixes this by putting an extra test in tcp_chr_connect(), and also adds an assert qemu_set_fd_handler2() to catch other such errors on all platforms, rather than just some. Signed-off-by: David Gibson Signed-off-by: Anthony Liguori --- iohandler.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'iohandler.c') diff --git a/iohandler.c b/iohandler.c index dea43552d2..a2d871bb91 100644 --- a/iohandler.c +++ b/iohandler.c @@ -56,6 +56,8 @@ int qemu_set_fd_handler2(int fd, { IOHandlerRecord *ioh; + assert(fd >= 0); + if (!fd_read && !fd_write) { QLIST_FOREACH(ioh, &io_handlers, next) { if (ioh->fd == fd) { -- cgit 1.4.1