* [PATCH] net: sunrpc: xprt.c: fix shift-out-of-bounds in xprt_calc_majortimeo
@ 2021-04-19 16:36 Kurt Manucredo
2021-04-19 16:58 ` Trond Myklebust
0 siblings, 1 reply; 2+ messages in thread
From: Kurt Manucredo @ 2021-04-19 16:36 UTC (permalink / raw)
To: trond.myklebust, anna.schumaker, bfields, chuck.lever, davem,
kuba, skhan
Cc: Kurt Manucredo, linux-nfs, netdev, linux-kernel,
linux-kernel-mentees, syzbot+ba2e91df8f74809417fa, gregkh
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 <fuzzybritches0@gmail.com>
---
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(struct rpc_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)
--
2.30.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] net: sunrpc: xprt.c: fix shift-out-of-bounds in xprt_calc_majortimeo
2021-04-19 16:36 [PATCH] net: sunrpc: xprt.c: fix shift-out-of-bounds in xprt_calc_majortimeo Kurt Manucredo
@ 2021-04-19 16:58 ` Trond Myklebust
0 siblings, 0 replies; 2+ messages in thread
From: Trond Myklebust @ 2021-04-19 16:58 UTC (permalink / raw)
To: bfields, fuzzybritches0, skhan, anna.schumaker, davem, chuck.lever, kuba
Cc: linux-kernel-mentees, linux-nfs, gregkh, netdev, linux-kernel,
syzbot+ba2e91df8f74809417fa
On Mon, 2021-04-19 at 16:36 +0000, Kurt Manucredo wrote:
> 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 <fuzzybritches0@gmail.com>
> ---
> 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(struct
> rpc_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
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2021-04-19 16:58 ` Trond Myklebust
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