linux-kernel - Re: [PATCH] userfaultfd: avoid the duplicated release for userfaultfd

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <1a463530-107d-0893-cecf-87ba42ebdbf6@windriver.com>
Date:   Wed, 15 Jul 2020 09:41:29 +0800
From:   "Xu, Yanfei" <yanfei.xu@...driver.com>
To:     linux-fsdevel@...r.kernel.org, linux-kernel@...r.kernel.org,
        Alexander Viro <viro@...iv.linux.org.uk>
Subject: Re: [PATCH] userfaultfd: avoid the duplicated release for
 userfaultfd_ctx

Add maintainer Alexander Viro  :)

On 7/15/20 12:12 AM, yanfei.xu@...driver.com wrote:
> From: Yanfei Xu <yanfei.xu@...driver.com>
> 
> when get_unused_fd_flags gets failure, userfaultfd_ctx_cachep will
> be freed by userfaultfd_fops's release function which is the
> userfaultfd_release. So we could return directly after fput().
> 
> userfaultfd_release()->userfaultfd_ctx_put(ctx)
> 
> Fixes: d08ac70b1e0d (Wire UFFD up to SELinux)
> Reported-by: syzbot+75867c44841cb6373570@...kaller.appspotmail.com
> Signed-off-by: Yanfei Xu <yanfei.xu@...driver.com>
> ---
>   fs/userfaultfd.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c
> index 3a4d6ac5a81a..e98317c15530 100644
> --- a/fs/userfaultfd.c
> +++ b/fs/userfaultfd.c
> @@ -2049,7 +2049,7 @@ SYSCALL_DEFINE1(userfaultfd, int, flags)
>   	fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC);
>   	if (fd < 0) {
>   		fput(file);
> -		goto out;
> +		return fd;
>   	}
>   
>   	ctx->owner = file_inode(file);
>