svcrdma: Address an integer overflow

Vulnerability Description

In the Linux kernel, the following vulnerability has been resolved: svcrdma: Address an integer overflow Dan Carpenter reports: > Commit 78147ca8b4a9 ("svcrdma: Add a "parsed chunk list" data > structure") from Jun 22, 2020 (linux-next), leads to the following > Smatch static checker warning: > > net/sunrpc/xprtrdma/svc_rdma_recvfrom.c:498 xdr_check_write_chunk() > warn: potential user controlled sizeof overflow 'segcount * 4 * 4' > > net/sunrpc/xprtrdma/svc_rdma_recvfrom.c > 488 static bool xdr_check_write_chunk(struct svc_rdma_recv_ctxt *rctxt) > 489 { > 490 u32 segcount; > 491 __be32 *p; > 492 > 493 if (xdr_stream_decode_u32(&rctxt->rc_stream, &segcount)) > ^^^^^^^^ > > 494 return false; > 495 > 496 /* A bogus segcount causes this buffer overflow check to fail. */ > 497 p = xdr_inline_decode(&rctxt->rc_stream, > --> 498 segcount * rpcrdma_segment_maxsz * sizeof(*p)); > > > segcount is an untrusted u32. On 32bit systems anything >= SIZE_MAX / 16 will > have an integer overflow and some those values will be accepted by > xdr_inline_decode().

References

• https://git.kernel.org/stable/c/21e1cf688fb0397788c8dd42e1e0b08d58ac5c7b
• https://git.kernel.org/stable/c/c1f8195bf68edd2cef0f18a4cead394075a54b5a
• https://git.kernel.org/stable/c/838dd342962cef4c320632a5af48d3c31f2f9877
• https://git.kernel.org/stable/c/4cbc3ba6dc2f746497cade60bcbaa82ae3696689
• https://git.kernel.org/stable/c/e5c440c227ecdc721f2da0dd88b6358afd1031a7
• https://git.kernel.org/stable/c/3c63d8946e578663b868cb9912dac616ea68bfd0