1 files changed, 25 insertions, 7 deletions

diff --git a/fs/nfsd/nfsctl.c b/fs/nfsd/nfsctl.c
index c4843467cfd4..a152694e016e 100644
--- a/fs/nfsd/nfsctl.c
+++ b/fs/nfsd/nfsctl.c
@@ -793,7 +793,7 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
 {
         char *mesg = buf;
         char *vers, *minorp, sign;
-        int len, num;
+        int len, num, remaining;
         unsigned minor;
         ssize_t tlen = 0;
         char *sep;
@@ -840,32 +840,50 @@ static ssize_t __write_versions(struct file *file, char *buf, size_t size)
                         }
                 next:
                         vers += len + 1;
-                        tlen += len;
                 } while ((len = qword_get(&mesg, vers, size)) > 0);
                 /* If all get turned off, turn them back on, as
                  * having no versions is BAD
                  */
                 nfsd_reset_versions();
         }
+
         /* Now write current state into reply buffer */
         len = 0;
         sep = "";
+        remaining = SIMPLE_TRANSACTION_LIMIT;
         for (num=2 ; num <= 4 ; num++)
                 if (nfsd_vers(num, NFSD_AVAIL)) {
-                        len += sprintf(buf+len, "%s%c%d", sep,
+                        len = snprintf(buf, remaining, "%s%c%d", sep,
                                        nfsd_vers(num, NFSD_TEST)?'+':'-',
                                        num);
                         sep = " ";
+
+                        if (len > remaining)
+                                break;
+                        remaining -= len;
+                        buf += len;
+                        tlen += len;
                 }
         if (nfsd_vers(4, NFSD_AVAIL))
-                for (minor = 1; minor <= NFSD_SUPPORTED_MINOR_VERSION; minor++)
-                        len += sprintf(buf+len, " %c4.%u",
+                for (minor = 1; minor <= NFSD_SUPPORTED_MINOR_VERSION;
+                     minor++) {
+                        len = snprintf(buf, remaining, " %c4.%u",
                                         (nfsd_vers(4, NFSD_TEST) &&
                                          nfsd_minorversion(minor, NFSD_TEST)) ?
                                                 '+' : '-',
                                         minor);
-        len += sprintf(buf+len, "\n");
-        return len;
+
+                        if (len > remaining)
+                                break;
+                        remaining -= len;
+                        buf += len;
+                        tlen += len;
+                }
+
+        len = snprintf(buf, remaining, "\n");
+        if (len > remaining)
+                return -EINVAL;
+        return tlen + len;
 }
 
 /**