Re: KMSAN: uninit-value in tomoyo_check_inet_address

From: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Date: Thu, May 16, 2019 at 3:13 PM
To: syzbot
Cc: <glider@google.com>, <jmorris@namei.org>,
[off-list ref],
[off-list ref], [off-list ref],
[off-list ref], [off-list ref]

On 2019/05/16 21:58, syzbot wrote:

quoted

Hello,

syzbot found the following crash on:

HEAD commit:    3b955a40 usb-fuzzer: main usb gadget fuzzer driver
git tree:       kmsan
console output: https://syzkaller.appspot.com/x/log.txt?x=1027e608a00000
kernel config:  https://syzkaller.appspot.com/x/.config?x=602468164ccdc30a
dashboard link: https://syzkaller.appspot.com/bug?extid=1018d578c410f9f37261
compiler:       clang version 9.0.0 (/home/glider/llvm/clang 06d00afa61eef8f7f501ebdb4e8612ea43ec2d78)

Unfortunately, I don't have any reproducer for this crash yet.

This should be already fixed in linux.git.

#syz fix: tomoyo: Check address length before reading address family

commit e6193f78bb689f3f424559bb45f4a091c8b314df
Author: Tetsuo Handa [off-list ref]
Date:   Fri Apr 12 19:59:36 2019 +0900

    tomoyo: Check address length before reading address family

    KMSAN will complain if valid address length passed to bind()/connect()/
    sendmsg() is shorter than sizeof("struct sockaddr"->sa_family) bytes.

    Signed-off-by: Tetsuo Handa [off-list ref]
    Signed-off-by: James Morris [off-list ref]

Apparently the fix didn't make it to 5.1, I'll cherry-pick it to KMSAN tree.
OOC, how did you know about this bug?

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