server-protocol: don't allow '../' path in 'name'

This will prevent any arbitrary file creation through glusterfs
by modifying the client bits.

Also check for the similar flaw inside posix too, so we prevent any
changes in layers in-between.

Fixes: bz#1625095

Signed-off-by: Amar Tumballi <amarts@redhat.com>
Change-Id: Id9fe0ef6e86459e8ed85ab947d977f058c5ae06e

1 files changed, 12 insertions, 0 deletions

diff --git a/xlators/protocol/server/src/server-resolve.c b/xlators/protocol/server/src/server-resolve.c
index 6ffb9098421..b3eda0e4c9e 100644
--- a/xlators/protocol/server/src/server-resolve.c
+++ b/xlators/protocol/server/src/server-resolve.c
@@ -311,6 +311,18 @@ resolve_entry_simple (call_frame_t *frame)
         /* expected @parent was found from the inode cache */
         gf_uuid_copy (state->loc_now->pargfid, resolve->pargfid);
         state->loc_now->parent = inode_ref (parent);
+
+        if (strstr (resolve->bname, "../")) {
+                /* Resolving outside the parent's tree is not allowed */
+                gf_msg (this->name, GF_LOG_ERROR, EPERM,
+                        PS_MSG_GFID_RESOLVE_FAILED,
+                        "%s: path sent by client not allowed",
+                        resolve->bname);
+                resolve->op_ret   = -1;
+                resolve->op_errno = EPERM;
+                ret = 1;
+                goto out;
+        }
         state->loc_now->name = resolve->bname;
 
         inode = inode_grep (state->itable, parent, resolve->bname);