Commit 1ec3911d authored Jan 25, 2013 by Cong Ding Committed by Alex Elder Jan 25, 2013

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 <dinggnu@gmail.com>
Reviewed-by: Alex Elder <elder@inktank.com>

parent c0430647

net/ceph/osdmap.c

+10 −18

Original line number	Diff line number	Diff line
		@@ -13,26 +13,18 @@

		char ceph_osdmap_state_str(char str, int len, int state)
		{
		int flag = 0;

		if (!len)
		goto done;
		return str;

		*str = '\0';
		if (state) {
		if (state & CEPH_OSD_EXISTS) {
		if ((state & CEPH_OSD_EXISTS) && (state & CEPH_OSD_UP))
		snprintf(str, len, "exists, up");
		else 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 {
		else if (state & CEPH_OSD_UP)
		snprintf(str, len, "up");
		else
		snprintf(str, len, "doesn't exist");
		}
		done:

		return str;
		}

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