[dm-devel] [PATCH] libmultipath: Don't chop const strings

[Benjamin Marzinski]

multipath was chopping sysfs attr strings in order to make sure that
ending whitespace didn't cause them to overflow their buffer. However
those strings were const strings. This patch makes multipath check how
much of the string length is ending whitespace, so that it can tell if
it will really overflow the buffer without chopping the const string.

Signed-off-by: Benjamin Marzinski <bmarzins at redhat.com>
---
 libmultipath/discovery.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

diff --git a/libmultipath/discovery.c b/libmultipath/discovery.c
index 228ffd3..a6ff658 100644
--- a/libmultipath/discovery.c
+++ b/libmultipath/discovery.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2005 Mike Anderson
  */
 #include <stdio.h>
+#include <ctype.h>
 #include <unistd.h>
 #include <fcntl.h>
 #include <sys/ioctl.h>
@@ -143,6 +144,7 @@ path_discovery (vector pathvec, struct config * conf, int flag)
 extern ssize_t								\
 sysfs_get_##fname (struct udev_device * udev, char * buff, size_t len)	\
 {									\
+	int l;							\
 	const char * attr;						\
 	const char * devname;						\
 									\
@@ -157,12 +159,14 @@ sysfs_get_##fname (struct udev_device * udev, char * buff, size_t len)	\
 			devname, #fname);				\
 		return -ENXIO;						\
 	}								\
-	if (strchop(attr) > len) {					\
+	for (l = strlen(attr); l >= 1 && isspace(attr[l-1]); l--);	\
+	if (l > len) {							\
 		condlog(3, "%s: overflow in attribute %s",		\
 			devname, #fname);				\
 		return -EINVAL;						\
 	}								\
-	return strlcpy(buff, attr, len);				\
+	strlcpy(buff, attr, len);					\
+	return strchop(buff);						\
 }
 
 declare_sysfs_get_str(devtype);
-- 
1.8.4.2