The Linux Kernel Mailing List
 help / color / mirror / Atom feed
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Peter Zijlstra <peterz@infradead.org>
Cc: syzbot <syzbot+9afaf6749e3a7aa1bdf3@syzkaller.appspotmail.com>,
	andrealmeid@igalia.com, dave@stgolabs.net, dvhart@infradead.org,
	linux-kernel@vger.kernel.org, mingo@redhat.com,
	syzkaller-bugs@googlegroups.com, tglx@linutronix.de
Subject: Re: [syzbot] [kernel?] KASAN: wild-memory-access Read in get_futex_key
Date: Tue, 27 May 2025 17:31:06 +0200	[thread overview]
Message-ID: <20250527153106.WFmvR15N@linutronix.de> (raw)
In-Reply-To: <20250527142217.GA7747@noisy.programming.kicks-ass.net>

On 2025-05-27 16:22:17 [+0200], Peter Zijlstra wrote:
> >  get_futex_key+0x595/0x1540 kernel/futex/core.c:587
> 
> Does the this help?

it avoids boom but reject FUTEX_NO_NODE. What about

diff --git a/kernel/futex/core.c b/kernel/futex/core.c
index 19a2c65f3d373..d0f5645eac61c 100644
--- a/kernel/futex/core.c
+++ b/kernel/futex/core.c
@@ -583,8 +583,9 @@ int get_futex_key(u32 __user *uaddr, unsigned int flags, union futex_key *key,
 		if (futex_get_value(&node, naddr))
 			return -EFAULT;
 
-		if (node != FUTEX_NO_NODE &&
-		    (node >= MAX_NUMNODES || !node_possible(node)))
+		if ((node != FUTEX_NO_NODE) &&
+		    (node < 0 || node > nr_node_ids ||
+		     !node_possible(node)))
 			return -EINVAL;
 	}
 

Sebastian

  reply	other threads:[~2025-05-27 15:31 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2025-05-27 13:36 [syzbot] [kernel?] KASAN: wild-memory-access Read in get_futex_key syzbot
2025-05-27 14:22 ` Peter Zijlstra
2025-05-27 15:31   ` Sebastian Andrzej Siewior [this message]
2025-05-27 15:39     ` Sebastian Andrzej Siewior

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20250527153106.WFmvR15N@linutronix.de \
    --to=bigeasy@linutronix.de \
    --cc=andrealmeid@igalia.com \
    --cc=dave@stgolabs.net \
    --cc=dvhart@infradead.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mingo@redhat.com \
    --cc=peterz@infradead.org \
    --cc=syzbot+9afaf6749e3a7aa1bdf3@syzkaller.appspotmail.com \
    --cc=syzkaller-bugs@googlegroups.com \
    --cc=tglx@linutronix.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox