Re: @(#)Mordred Labs advisory 0x0003: Buffer overflow in PostgreSQL (fwd)

Vince Vielhaber <vev@michvhf.com> writes:
> Here's yet another.  He claims malicious code can be run on the server
> with this one.

regression=# select repeat('xxx',1431655765);
server closed the connection unexpectedly

This is probably caused by integer overflow in calculating the size of
the repeat's result buffer.  It'd take some considerable doing to create
an arbitrary-code exploit, but perhaps could be done.  Anyone want to
investigate a patch?  I think we likely need something like
bufsize = input_length * repeats;
+    /* check for overflow in multiplication */
+    if (bufsize / repeats != input_length)
+        elog(ERROR, "repeat result too long");

but I haven't thought it through in detail.
        regards, tom lane