Revert due to potential file modes race condition

ticket: 6002
status: open

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@20538 dc483132-0cff-0310-8789-dd5450dbe970

1 files changed, 14 insertions, 18 deletions

diff --git a/src/lib/krb5/rcache/rc_io.c b/src/lib/krb5/rcache/rc_io.c
index 84c8338..59d15c2 100644
--- a/src/lib/krb5/rcache/rc_io.c
+++ b/src/lib/krb5/rcache/rc_io.c
@@ -68,6 +68,7 @@ getdir(void)
 krb5_error_code
 krb5_rc_io_creat(krb5_context context, krb5_rc_iostuff *d, char **fn)
 {
+    char *c;
     krb5_int16 rc_vno = htons(KRB5_RC_VNO);
     krb5_error_code retval = 0;
     int do_not_unlink = 0;
@@ -85,29 +86,24 @@ krb5_rc_io_creat(krb5_context context, krb5_rc_iostuff *d, char **fn)
 	d->fd = THREEPARAMOPEN(d->fn, O_WRONLY | O_CREAT | O_TRUNC | O_EXCL |
 			       O_BINARY, 0600);
     } else {
-	if (asprintf(&d->fn, "%s%skrb5_RCXXXXXX",
-		     dir, PATH_SEPARATOR) < 0) {
+	if (asprintf(&d->fn, "%s%skrb5_RC%daaa",
+		     dir, PATH_SEPARATOR, (int) UNIQUE) < 0) {
 	    d->fn = NULL;
 	    return KRB5_RC_IO_MALLOC;
 	}
-	d->fd = mkstemp(d->fn);
-	if (d->fd != -1) {
-#if defined(HAVE_FCHMOD) || defined(HAVE_CHMOD)
-#ifdef HAVE_FCHMOD
-	    retval = fchmod(d->fd, 0600);
-#else
-	    retval = chmod(d->fn, 0600);
-#endif
-	    if (retval == -1) {
-		retval = KRB5_RC_IO_UNKNOWN;
-		krb5_set_error_message(context, retval,
-				       "Cannot chmod replay cache file %s: %s",
-				       d->fn, strerror(errno));
-		goto cleanup;
+	c = d->fn + strlen(d->fn) - 3;
+	while ((d->fd = THREEPARAMOPEN(d->fn, O_WRONLY | O_CREAT | O_TRUNC |
+				       O_EXCL | O_BINARY, 0600)) == -1)	{
+	    if ((c[2]++) == 'z') {
+		c[2] = 'a';
+		if ((c[1]++) == 'z') {
+		    c[1] = 'a';
+		    if ((c[0]++) == 'z')
+			break; /* sigh */
+		}
 	    }
-#endif
 	}
-	if (retval != 0 && d->fd != -1 && fn) {
+	if (fn) {
 	    *fn = strdup(d->fn + dirlen);
 	    if (*fn == NULL) {
 		free(d->fn);