From 1957dd6aff931877fc22699d8f2d4be8728014ba Mon Sep 17 00:00:00 2001 From: Andrew Cooper Date: Fri, 28 Jun 2024 11:24:14 +0100 Subject: [PATCH] tools/libxs: Fix CLOEXEC handling in get_socket() get_socket() opens a socket, then uses fcntl() to set CLOEXEC. This is racy with exec(). Open the socket with SOCK_CLOEXEC. Use the same compatibility strategy as O_CLOEXEC on ancient versions of Linux. Reported-by: Frediano Ziglio Signed-off-by: Andrew Cooper Reviewed-by: Juergen Gross Acked-by: Anthony PERARD --- tools/libs/store/xs.c | 14 ++++++++------ 1 file changed, 8 insertions(+), 6 deletions(-) diff --git a/tools/libs/store/xs.c b/tools/libs/store/xs.c index 037e79d98b..11a766c508 100644 --- a/tools/libs/store/xs.c +++ b/tools/libs/store/xs.c @@ -44,6 +44,10 @@ #define O_CLOEXEC 0 #endif +#ifndef SOCK_CLOEXEC +#define SOCK_CLOEXEC 0 +#endif + struct xs_stored_msg { XEN_TAILQ_ENTRY(struct xs_stored_msg) list; struct xsd_sockmsg hdr; @@ -207,16 +211,14 @@ int xs_fileno(struct xs_handle *h) static int get_socket(const char *connect_to) { struct sockaddr_un addr; - int sock, saved_errno, flags; + int sock, saved_errno; - sock = socket(PF_UNIX, SOCK_STREAM, 0); + sock = socket(PF_UNIX, SOCK_STREAM | SOCK_CLOEXEC, 0); if (sock < 0) return -1; - if ((flags = fcntl(sock, F_GETFD)) < 0) - goto error; - flags |= FD_CLOEXEC; - if (fcntl(sock, F_SETFD, flags) < 0) + /* Compat for non-SOCK_CLOEXEC environments. Racy. */ + if (!SOCK_CLOEXEC && !set_cloexec(sock)) goto error; addr.sun_family = AF_UNIX;