From 335c54bdc4d3bacdbd619ec95cd0b352435bd37f Mon Sep 17 00:00:00 2001 From: Chuck Lever Date: Thu, 23 Apr 2009 19:32:25 -0400 Subject: NFSD: Prevent a buffer overflow in svc_xprt_names() The svc_xprt_names() function can overflow its buffer if it's so near the end of the passed in buffer that the "name too long" string still doesn't fit. Of course, it could never tell if it was near the end of the passed in buffer, since its only caller passes in zero as the buffer length. Let's make this API a little safer. Change svc_xprt_names() so it *always* checks for a buffer overflow, and change its only caller to pass in the correct buffer length. If svc_xprt_names() does overflow its buffer, it now fails with an ENAMETOOLONG errno, instead of trying to write a message at the end of the buffer. I don't like this much, but I can't figure out a clean way that's always safe to return some of the names, *and* an indication that the buffer was not long enough. The displayed error when doing a 'cat /proc/fs/nfsd/portlist' is "File name too long". Signed-off-by: Chuck Lever Signed-off-by: J. Bruce Fields --- include/linux/sunrpc/svc_xprt.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'include/linux/sunrpc') diff --git a/include/linux/sunrpc/svc_xprt.h b/include/linux/sunrpc/svc_xprt.h index d790c52525c..2223ae0b5ed 100644 --- a/include/linux/sunrpc/svc_xprt.h +++ b/include/linux/sunrpc/svc_xprt.h @@ -83,7 +83,7 @@ int svc_port_is_privileged(struct sockaddr *sin); int svc_print_xprts(char *buf, int maxlen); struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name, const sa_family_t af, const unsigned short port); -int svc_xprt_names(struct svc_serv *serv, char *buf, int buflen); +int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen); static inline void svc_xprt_get(struct svc_xprt *xprt) { -- cgit v1.2.3