From ea7d8b95e2fcb81f68b04ed7787a3dbda023991a Mon Sep 17 00:00:00 2001 From: Siddhesh Poyarekar Date: Thu, 27 Mar 2014 19:48:15 +0530 Subject: Avoid overlapping addresses to stpcpy calls in nscd (BZ #16760) Calls to stpcpy from nscd netgroups code will have overlapping source and destination when all three values in the returned triplet are non-NULL and in the expected (host,user,domain) order. This is seen in valgrind as: ==3181== Source and destination overlap in stpcpy(0x19973b48, 0x19973b48) ==3181== at 0x4C2F30A: stpcpy (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so) ==3181== by 0x12567A: addgetnetgrentX (string3.h:111) ==3181== by 0x12722D: addgetnetgrent (netgroupcache.c:665) ==3181== by 0x11114C: nscd_run_worker (connections.c:1338) ==3181== by 0x4E3C102: start_thread (pthread_create.c:309) ==3181== by 0x59B81AC: clone (clone.S:111) ==3181== Fix this by using memmove instead of stpcpy. --- nscd/netgroupcache.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-) (limited to 'nscd') diff --git a/nscd/netgroupcache.c b/nscd/netgroupcache.c index 5d15aa4..820d823 100644 --- a/nscd/netgroupcache.c +++ b/nscd/netgroupcache.c @@ -216,6 +216,10 @@ addgetnetgrentX (struct database_dyn *db, int fd, request_header *req, const char *nuser = data.val.triple.user; const char *ndomain = data.val.triple.domain; + size_t hostlen = strlen (nhost ?: "") + 1; + size_t userlen = strlen (nuser ?: "") + 1; + size_t domainlen = strlen (ndomain ?: "") + 1; + if (nhost == NULL || nuser == NULL || ndomain == NULL || nhost > nuser || nuser > ndomain) { @@ -233,9 +237,6 @@ addgetnetgrentX (struct database_dyn *db, int fd, request_header *req, : last + strlen (last) + 1 - buffer); /* We have to make temporary copies. */ - size_t hostlen = strlen (nhost ?: "") + 1; - size_t userlen = strlen (nuser ?: "") + 1; - size_t domainlen = strlen (ndomain ?: "") + 1; size_t needed = hostlen + userlen + domainlen; if (buflen - req->key_len - bufused < needed) @@ -269,9 +270,12 @@ addgetnetgrentX (struct database_dyn *db, int fd, request_header *req, } char *wp = buffer + buffilled; - wp = stpcpy (wp, nhost) + 1; - wp = stpcpy (wp, nuser) + 1; - wp = stpcpy (wp, ndomain) + 1; + wp = memmove (wp, nhost ?: "", hostlen); + wp += hostlen; + wp = memmove (wp, nuser ?: "", userlen); + wp += userlen; + wp = memmove (wp, ndomain ?: "", domainlen); + wp += domainlen; buffilled = wp - buffer; ++nentries; } -- cgit v1.1