libuafs: return error on symlink to self

if we are symlinked to ourself directly, return ELOOP.

Change-Id: I408012c4a9afb6bab0e917677c940f65ad59c697
Reviewed-on: http://gerrit.openafs.org/10240
Tested-by: BuildBot <buildbot@rampaginggeek.com>
Reviewed-by: Derrick Brashear <shadow@your-file-system.com>

diff --git a/src/afs/UKERNEL/afs_usrops.c b/src/afs/UKERNEL/afs_usrops.c
index efb52ea..f6195b9 100644 (file)
--- a/src/afs/UKERNEL/afs_usrops.c
+++ b/src/afs/UKERNEL/afs_usrops.c
@@ -1657,12 +1657,13 @@ uafs_RPCStatsClearPeer(void)
  * Lookup the target of a symbolic link
  * Call VN_HOLD on the output vnode if successful.
  * Returns zero on success, error code on failure.
+ * If provided, use a path for confirming we are not linked to ourself.
  *
  * Note: Caller must hold the AFS global lock.
  */
-int
-uafs_LookupLink(struct usr_vnode *vp, struct usr_vnode *parentVp,
-               struct usr_vnode **vpp)
+static int
+uafs_LookupLinkPath(struct usr_vnode *vp, struct usr_vnode *parentVp,
+                   char *ppathP, struct usr_vnode **vpp)
 {
     int code;
     int len;
@@ -1699,6 +1700,16 @@ uafs_LookupLink(struct usr_vnode *vp, struct usr_vnode *parentVp,
     len = MAX_OSI_PATH + 1 - uio.uio_resid;
     pathP[len] = '\0';
 
+    /* are we linked to ourname or ./ourname? ELOOP */
+    if (ppathP) {
+       if ((strcmp(pathP, ppathP) == 0) ||
+           ((pathP[0] == '.') &&
+            (pathP[1] == '/') &&
+            (strcmp(&(pathP[2]), ppathP) == 0))) {
+           return ELOOP;
+       }
+    }
+
     /*
      * Find the target of the symbolic link
      */
@@ -1829,7 +1840,7 @@ uafs_LookupName(char *path, struct usr_vnode *parentVp,
                    afs_osi_Free(tmpPath, strlen(path) + 1);
                    return code;
                }
-               code = uafs_LookupLink(nextVp, vp, &linkVp);
+               code = uafs_LookupLinkPath(nextVp, vp, NULL, &linkVp);
                if (code) {
                    VN_RELE(vp);
                    VN_RELE(nextVp);
@@ -1860,6 +1871,13 @@ uafs_LookupName(char *path, struct usr_vnode *parentVp,
     return 0;
 }
 
+int
+uafs_LookupLink(struct usr_vnode *vp, struct usr_vnode *parentVp,
+               struct usr_vnode **vpp)
+{
+    return uafs_LookupLinkPath(vp, parentVp, NULL, vpp);
+}
+
 /*
  * Lookup the parent of a file or directory given its path
  * Call VN_HOLD on the output vnode if successful.