From: Al Viro <viro@ZenIV.linux.org.uk>
To: Jann Horn <jannh@google.com>
Cc: Richard Henderson <rth@twiddle.net>,
Ivan Kokshaysky <ink@jurassic.park.msu.ru>,
Matt Turner <mattst88@gmail.com>,
"David S. Miller" <davem@davemloft.net>,
linux-kernel@vger.kernel.org,
"Eric W. Biederman" <ebiederm@xmission.com>,
linux-alpha@vger.kernel.org, sparclinux@vger.kernel.org,
security@kernel.org, Christoph Hellwig <hch@infradead.org>,
Serge Hallyn <serge@hallyn.com>
Subject: Re: [PATCH] sys: don't hold uts_sem while accessing userspace memory
Date: Mon, 25 Jun 2018 17:41:09 +0100 [thread overview]
Message-ID: <20180625164109.GF30522@ZenIV.linux.org.uk> (raw)
In-Reply-To: <20180625163410.216168-1-jannh@google.com>
On Mon, Jun 25, 2018 at 06:34:10PM +0200, Jann Horn wrote:
> + char tmp[32];
>
> - if (namelen > 32)
> + if (namelen < 0 || namelen > 32)
> namelen = 32;
>
> down_read(&uts_sem);
> kname = utsname()->domainname;
> len = strnlen(kname, namelen);
> - if (copy_to_user(name, kname, min(len + 1, namelen)))
> - err = -EFAULT;
> + len = min(len + 1, namelen);
> + memcpy(tmp, kname, len);
> up_read(&uts_sem);
>
> - return err;
> + if (copy_to_user(name, tmp, len))
> + return -EFAULT;
Infoleak, and similar in a lot of other places.
next prev parent reply other threads:[~2018-06-25 16:41 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-25 16:34 [PATCH] sys: don't hold uts_sem while accessing userspace memory Jann Horn
2018-06-25 16:41 ` Al Viro [this message]
2018-06-25 18:16 ` Jann Horn
2018-06-26 17:43 ` Ben Hutchings
2018-06-27 12:29 ` Jann Horn
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