- a malicious server may send path names that translate out of the

local cvs tree on the client, enabling the server to overwrite files
on the client.

- a client may read files outside the repository using the -p flag
with the checkout command.

ok deraadt@

2 files changed, 21 insertions, 0 deletions

diff --git a/gnu/usr.bin/cvs/src/client.c b/gnu/usr.bin/cvs/src/client.c
index e234af594fe..57739524ee2 100644
--- a/gnu/usr.bin/cvs/src/client.c
+++ b/gnu/usr.bin/cvs/src/client.c
@@ -1003,6 +1003,20 @@ call_in_directory (pathname, func, data)
     char *rdirp;
     int reposdirname_absolute;
 
+    /*
+     * For security reasons, if PATHNAME is absolute or attempts to
+     * ascend outside of the current sandbox, we abort.  The server should not
+     * send us anything but relative paths which remain inside the sandbox
+     * here.  Anything less means a trojan CVS server could create and edit
+     * arbitrary files on the client.
+     */
+    if (isabsolute (pathname) || pathname_levels (pathname) > 0)
+    {
+        error (0, 0,
+               "Server attempted to update a file via an invalid pathname:");
+        error (1, 0, "`%s'.", pathname);
+    }
+
     reposname = NULL;
     read_line (&reposname);
     assert (reposname != NULL);
diff --git a/gnu/usr.bin/cvs/src/modules.c b/gnu/usr.bin/cvs/src/modules.c
index a4658815d24..c588b71cd04 100644
--- a/gnu/usr.bin/cvs/src/modules.c
+++ b/gnu/usr.bin/cvs/src/modules.c
@@ -170,6 +170,13 @@ do_module (db, mname, m_type, msg, callback_proc, where, shorten,
     if (isabsolute (mname))
 	error (1, 0, "Absolute module reference invalid: `%s'", mname);
 
+    /* Similarly for directories that attempt to step above the root of the
+     * repository.
+     */
+    if (pathname_levels (mname) > 0)
+	error (1, 0, "up-level in module reference (`..') invalid: `%s'.",
+               mname);
+
     /* if this is a directory to ignore, add it to that list */
     if (mname[0] == '!' && mname[1] != '\0')
     {