Re: [PATCH] net: sunrpc: xprt.c: fix shift-out-of-bounds in xprt_calc_majortimeo
From: Trond Myklebust <hidden>
Date: 2021-04-19 16:58:15
Also in:
linux-nfs, lkml, netdev
On Mon, 2021-04-19 at 16:36 +0000, Kurt Manucredo wrote:
quoted hunk ↗ jump to hunk
Fix shift-out-of-bounds in xprt_calc_majortimeo(). UBSAN: shift-out-of-bounds in net/sunrpc/xprt.c:658:14 shift exponent 536871232 is too large for 64-bit type 'long u Reported-by: syzbot+ba2e91df8f74809417fa@syzkaller.appspotmail.com Signed-off-by: Kurt Manucredo <redacted> --- net/sunrpc/xprt.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 691ccf8049a4..07128ac3d51d 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c@@ -655,7 +655,10 @@ static unsigned long xprt_calc_majortimeo(structrpc_rqst *req) unsigned long majortimeo = req->rq_timeout; if (to->to_exponential) - majortimeo <<= to->to_retries; + if (to->to_retries >= sizeof(majortimeo) * 8) + majortimeo = to->to_maxval; + else + majortimeo <<= to->to_retries; else majortimeo += to->to_increment * to->to_retries; if (majortimeo > to->to_maxval || majortimeo == 0)
I've already stated on the mailing list that I'm not accepting any changes to xprt_calc_majortimeo() for this problem. There is a fix to the NFS mount code that addresses this bounds issue, and that commit is already being tested in linux-next. -- Trond Myklebust Linux NFS client maintainer, Hammerspace trond.myklebust@hammerspace.com _______________________________________________ Linux-kernel-mentees mailing list Linux-kernel-mentees@lists.linuxfoundation.org https://lists.linuxfoundation.org/mailman/listinfo/linux-kernel-mentees