From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A959C2E762C; Mon, 17 Aug 2026 15:18:05 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786979886; cv=none; b=qWZlepQ9uxQs34H/oBfS7bCIW0isuDMSnXSNJhrR/UZpHXrEy6E4xt/rncxhEoZMIH4uA1U2F2sU0MkAO3Xn9/QY8X6SN4X8D1OHYlK/QzvGbyX5h5+uQQc1SkuDYu4wfeCjKoFXZz4pcJT9+PT/x5Z0VMPyrdouYmPBpLpPxjw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786979886; c=relaxed/simple; bh=KR8nTmlIC37oC5cF5ji3JtpqEriKdTwrV5SHVQRqFQg=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=poe3dOC4MjU3/gK0lwo+oaEfKbJ7DK5DzLvA51O3PTsHgYifdzatov311944uoJtYe/gHE/fZTMlhkzo7PdfARJX0tiDfdG6VkhxkVGcodBVJCY8AhYODTibmXgkCNII2sd5+iFIZN/bmVVF3tZ4ts2zn7/6wyNCCLi3VWSbs4w= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=FSywC9Yq; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="FSywC9Yq" Received: by smtp.kernel.org (Postfix) with ESMTPSA id AEF741F000E9; Mon, 17 Aug 2026 15:18:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786979885; bh=ltBVGKLdl5ZbrRiEh0cIz8ROWesg4Dk4ACnQ3Fy99E8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FSywC9YqvWIFb+6o41mthyg+AZ9h0zayc9qnwVeDA+Il9NKEkFKC7WGbx+CiNvfBx 3h8/KgVPCg4j7efVRQb3mBcIFMiUurZdsUrOWklQSL1CSu61xvjVASZjuvH5ccV1NB jQQp/xmzEr3TwZoyMyrhzogH8ZMnNCdXeA3t9JHA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, AutonomousCodeSecurity@microsoft.com, Yuan Tan , "Cen Zhang (Microsoft)" , NeilBrown , Herbert Xu , Sasha Levin Subject: [PATCH 6.1 381/609] rhashtable: clear stale iter->p on table restart Date: Mon, 17 Aug 2026 15:31:17 +0200 Message-ID: <20260817132557.012878011@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260817132543.039278408@linuxfoundation.org> References: <20260817132543.039278408@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Cen Zhang (Microsoft) [ Upstream commit 8173f7e2ce67e6ca1d4763f3da14e5b01ce77456 ] rhashtable_walk_start_check() has two restart paths when resuming a walk. When iter->walker.tbl is valid, it re-validates iter->p against the table and sets iter->p = NULL if the object is gone. When iter->walker.tbl is NULL (table was freed during resize), it resets slot and skip but forgets to clear iter->p. rhashtable_walk_next() then dereferences the stale iter->p, reading freed memory. This is a use-after-free. Any caller that does multi-fragment rhashtable walks across walk_stop/walk_start boundaries is affected. Concrete cases include netlink_diag (__netlink_diag_dump in net/netlink/diag.c) and TIPC (tipc_nl_sk_walk in net/tipc/socket.c). Crash stack (netlink_diag): BUG: KASAN: slab-use-after-free in rhashtable_walk_next+0x365/0x3c0 Read of size 8 at addr ffff88801a9d2438 (freed kmalloc-2k, offset 1080) Call Trace: rhashtable_walk_next+0x365/0x3c0 (lib/rhashtable.c:1016) __netlink_diag_dump+0x160/0x760 (net/netlink/diag.c:122) netlink_diag_dump+0xc2/0x240 netlink_dump+0x5bc/0x1270 netlink_recvmsg+0x7a3/0x980 sock_recvmsg+0x1bc/0x200 __sys_recvfrom+0x1d4/0x2c0 Fixes: 5d240a8936f6 ("rhashtable: improve rhashtable_walk stability when stop/start used.") Cc: Reported-by: AutonomousCodeSecurity@microsoft.com Reported-by: Yuan Tan Closes: https://lore.kernel.org/linux-crypto/CAB8m9Wh559e+=n8z51gB8DrbEyCc2mc0MgGjrRR6_VXBmU=2AQ@mail.gmail.com Signed-off-by: Cen Zhang (Microsoft) Reviewed-by: NeilBrown Signed-off-by: Herbert Xu Signed-off-by: Sasha Levin --- lib/rhashtable.c | 1 + 1 file changed, 1 insertion(+) diff --git a/lib/rhashtable.c b/lib/rhashtable.c index e12bbfb240b81..c977468291ea0 100644 --- a/lib/rhashtable.c +++ b/lib/rhashtable.c @@ -730,6 +730,7 @@ int rhashtable_walk_start_check(struct rhashtable_iter *iter) iter->walker.tbl = rht_dereference_rcu(ht->tbl, ht); iter->slot = 0; iter->skip = 0; + iter->p = NULL; return -EAGAIN; } -- 2.53.0