From b3dd1b8c295636e64ceb14cdc4db6420d7319e38 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" Date: Sun, 17 Aug 2014 11:45:17 +0200 Subject: monitor: fix use after free The function monitor_fdset_dup_fd_find_remove() references member of 'mon_fdset' which - when remove flag is set - may be freed in function monitor_fdset_cleanup(). remove is set by monitor_fdset_dup_fd_remove which in practice does not need the returned value, so make it void, and return -1 from monitor_fdset_dup_fd_find_remove. Reported-by: zhanghailiang Signed-off-by: Michael S. Tsirkin Signed-off-by: Luiz Capitulino --- include/monitor/monitor.h | 2 +- monitor.c | 8 +++++--- stubs/fdset-remove-fd.c | 3 +-- 3 files changed, 7 insertions(+), 6 deletions(-) diff --git a/include/monitor/monitor.h b/include/monitor/monitor.h index 3d6929d6cd..78a5fc8197 100644 --- a/include/monitor/monitor.h +++ b/include/monitor/monitor.h @@ -64,7 +64,7 @@ AddfdInfo *monitor_fdset_add_fd(int fd, bool has_fdset_id, int64_t fdset_id, Error **errp); int monitor_fdset_get_fd(int64_t fdset_id, int flags); int monitor_fdset_dup_fd_add(int64_t fdset_id, int dup_fd); -int monitor_fdset_dup_fd_remove(int dup_fd); +void monitor_fdset_dup_fd_remove(int dup_fd); int monitor_fdset_dup_fd_find(int dup_fd); #endif /* !MONITOR_H */ diff --git a/monitor.c b/monitor.c index 48f0fdc7e9..34cee74eb3 100644 --- a/monitor.c +++ b/monitor.c @@ -2542,8 +2542,10 @@ static int monitor_fdset_dup_fd_find_remove(int dup_fd, bool remove) if (QLIST_EMPTY(&mon_fdset->dup_fds)) { monitor_fdset_cleanup(mon_fdset); } + return -1; + } else { + return mon_fdset->id; } - return mon_fdset->id; } } } @@ -2555,9 +2557,9 @@ int monitor_fdset_dup_fd_find(int dup_fd) return monitor_fdset_dup_fd_find_remove(dup_fd, false); } -int monitor_fdset_dup_fd_remove(int dup_fd) +void monitor_fdset_dup_fd_remove(int dup_fd) { - return monitor_fdset_dup_fd_find_remove(dup_fd, true); + monitor_fdset_dup_fd_find_remove(dup_fd, true); } int monitor_handle_fd_param(Monitor *mon, const char *fdname) diff --git a/stubs/fdset-remove-fd.c b/stubs/fdset-remove-fd.c index b3886d9f45..7f6d61e619 100644 --- a/stubs/fdset-remove-fd.c +++ b/stubs/fdset-remove-fd.c @@ -1,7 +1,6 @@ #include "qemu-common.h" #include "monitor/monitor.h" -int monitor_fdset_dup_fd_remove(int dupfd) +void monitor_fdset_dup_fd_remove(int dupfd) { - return -1; } -- cgit v1.2.1