From 1ec3911dbd19076bcdfe5540096ff67f91a6ec02 Mon Sep 17 00:00:00 2001 From: Cong Ding Date: Fri, 25 Jan 2013 17:48:59 -0600 Subject: [PATCH] libceph: fix undefined behavior when using snprintf() The variable "str" is used as both the source and destination in function snprintf(), which is undefined behavior based on C11. The original description in C11 is: "If copying takes place between objects that overlap, the behavior is undefined." And, the function of ceph_osdmap_state_str() is to return the osdmap state, so it should return "doesn't exist" when all the conditions are not satisfied. I fix it in this patch. [elder@inktank.com: shortened the commit message] Signed-off-by: Cong Ding Reviewed-by: Alex Elder --- net/ceph/osdmap.c | 28 ++++++++++------------------ 1 file changed, 10 insertions(+), 18 deletions(-) diff --git a/net/ceph/osdmap.c b/net/ceph/osdmap.c index 369f03b..3c61e216 100644 --- a/net/ceph/osdmap.c +++ b/net/ceph/osdmap.c @@ -13,26 +13,18 @@ char *ceph_osdmap_state_str(char *str, int len, int state) { - int flag = 0; - if (!len) - goto done; - - *str = '\0'; - if (state) { - if (state & CEPH_OSD_EXISTS) { - snprintf(str, len, "exists"); - flag = 1; - } - if (state & CEPH_OSD_UP) { - snprintf(str, len, "%s%s%s", str, (flag ? ", " : ""), - "up"); - flag = 1; - } - } else { + return str; + + if ((state & CEPH_OSD_EXISTS) && (state & CEPH_OSD_UP)) + snprintf(str, len, "exists, up"); + else if (state & CEPH_OSD_EXISTS) + snprintf(str, len, "exists"); + else if (state & CEPH_OSD_UP) + snprintf(str, len, "up"); + else snprintf(str, len, "doesn't exist"); - } -done: + return str; } -- 2.7.4