AZL-55020

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/svcrdmarecvfrom.c:498 xdrcheckwrite_chunk() warn: potential user controlled sizeof overflow 'segcount * 4 * 4'

net/sunrpc/xprtrdma/svcrdmarecvfrom.c 488 static bool xdrcheckwritechunk(struct svcrdmarecvctxt *rctxt) 489 { 490 u32 segcount; 491 __be32 *p; 492 493 if (xdrstreamdecodeu32(&rctxt->rcstream, &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 * rpcrdmasegmentmaxsz * sizeof(*p));

segcount is an untrusted u32. On 32bit systems anything >= SIZEMAX / 16 will have an integer overflow and some those values will be accepted by xdrinline_decode().