From patchwork Thu Feb 22 10:50:13 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Eric Dumazet X-Patchwork-Id: 13567045 X-Patchwork-Delegate: kuba@kernel.org Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6E2BC44C84 for ; Thu, 22 Feb 2024 10:50:33 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.219.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708599034; cv=none; b=svY3TTpzg69Hp4CV6VJWxstUXA6VgTsqjohCPxjeR7OnVzlWitf76Nn3aZEPXdpLYQQoXo0QgJv2ilqiYS/w2JlO2tmoLe0IvRsN8h5fOVnjDih1cmTp/pc5GF0M85Uw52tFy7sE7KZ2toboc/xsq6lJBlt+mSSUkH3UeTgsi9U= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708599034; c=relaxed/simple; bh=Xy0+n9Pw6Ld7r3q9C5w6TjpnfVazfe7dZANFfUTESLo=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=hsRUCPRg4OuqwnvYDM/pVUxaYLNTmz7Uz4vpNWYVC6xj38OSHwC455paO6/Dkwz9eVLKa7OJbhXNZ3OLMOZhO9dvTPwx/5DgDWPmjNPtzrPPgEqeZ1COCAxvHelUFqljUl8latYKkjqxYK7ONJJvUg5EEFqqbL/tIIJyvOHQ/zA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=WZeh9EBn; arc=none smtp.client-ip=209.85.219.202 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--edumazet.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="WZeh9EBn" Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-dccc49ef73eso9311258276.2 for ; Thu, 22 Feb 2024 02:50:33 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20230601; t=1708599032; x=1709203832; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=pNsJx8P4mNBhoYU0JJHzFcUPUoA6dHzaqJZ3PEQd6/Q=; b=WZeh9EBnspZYCGAEcor62MZZl2Kvhp4g7H4pRMXAWAGhDp+8oWPCZrDkLJVuVnn00k xNIeMCG4o8fyRv9JJBQljHtBqsMQZYWG3ic0bFIkM+6e7GhDvGkMk0ezVv/XS7u9ZuP+ ipBzXfTUKAK1M8zJEjGQ6lxhUR8qeyqAtfVzksH6BmiW5wJDsWhUYbybmIPtHCX9hgk6 yqGugpSFoAuwH4wQVhgzeOYZacPIZO75tizui2AZoWKeeBqqCbuGpxEijvRaEW2Liw0Q nf1dGYlTyfjQ9DIqEShXkjTgWTxbKtn2vkRMVwx9v3TM9d1+vKuKc2tXHvgGHKS7bQDw Dd8Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1708599032; x=1709203832; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=pNsJx8P4mNBhoYU0JJHzFcUPUoA6dHzaqJZ3PEQd6/Q=; b=o9eINQnmE1b+slu07vyhAYmRvTvPTJFcdocA6KgORjYI2q/ZUVE2dz0CLVtWfU+E24 1ams8es+7/M++rkgyxyLBnS1Nhz2nAEKzMNGzB0GYQhQ6zPZFBKki6vI10++vwhIO6lc 9csy7n8DYGk2lce01Bk1L6vqGj1udV0x/Bvr7n3UTPblkPlApsv+XMDJFfsoVk8K0i8F aRZdWc1ry8W3wOZSYCbg58xT5eJvXsA8CSyBJl8hBO/GxO4SICs6araPJP9/waF+EG+J MaMEfKyFECR2RY+M/RwwSN+emLf9hnnnL81my0Yx3LyJ6KxKUaVTXHxeNU5me4Gfnrt6 BA0A== X-Gm-Message-State: AOJu0YxRnnt0bNKCtfcHOytO+TuopUJ4ugpwyOA8DJwg8xXzFodviXVq 3Xw8/K6L8AJXiDnGBZ1Ss0DFwcedQ24HWkRVe/lvZPu5OKXivvhUYe00oydJ0BPNd+dCW7beNY8 AgJIG15vcnw== X-Google-Smtp-Source: AGHT+IH67Bwomz6lNyUG4qF2T2v4SNFgJ1OuHILc0NTVnUocpcDTloDBdzjyw0qcB7rDIlBwlb/mkWtO7d0EFA== X-Received: from edumazet1.c.googlers.com ([fda3:e722:ac3:cc00:2b:7d90:c0a8:395a]) (user=edumazet job=sendgmr) by 2002:a05:6902:1081:b0:dc7:63e7:7a5c with SMTP id v1-20020a056902108100b00dc763e77a5cmr96923ybu.11.1708599032513; Thu, 22 Feb 2024 02:50:32 -0800 (PST) Date: Thu, 22 Feb 2024 10:50:13 +0000 In-Reply-To: <20240222105021.1943116-1-edumazet@google.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20240222105021.1943116-1-edumazet@google.com> X-Mailer: git-send-email 2.44.0.rc1.240.g4c46232300-goog Message-ID: <20240222105021.1943116-7-edumazet@google.com> Subject: [PATCH v2 net-next 06/14] netlink: hold nlk->cb_mutex longer in __netlink_dump_start() From: Eric Dumazet To: "David S . Miller" , Jakub Kicinski , Paolo Abeni Cc: netdev@vger.kernel.org, Ido Schimmel , Jiri Pirko , eric.dumazet@gmail.com, Eric Dumazet X-Patchwork-Delegate: kuba@kernel.org __netlink_dump_start() releases nlk->cb_mutex right before calling netlink_dump() which grabs it again. This seems dangerous, even if KASAN did not bother yet. Add a @lock_taken parameter to netlink_dump() to let it grab the mutex if called from netlink_recvmsg() only. Signed-off-by: Eric Dumazet Reviewed-by: Jiri Pirko --- net/netlink/af_netlink.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-) diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c index 9c962347cf859f16fc76e4d8a2fd22cdb3d142d6..94f3860526bfaa5793e8b3917250ec0e751687b5 100644 --- a/net/netlink/af_netlink.c +++ b/net/netlink/af_netlink.c @@ -130,7 +130,7 @@ static const char *const nlk_cb_mutex_key_strings[MAX_LINKS + 1] = { "nlk_cb_mutex-MAX_LINKS" }; -static int netlink_dump(struct sock *sk); +static int netlink_dump(struct sock *sk, bool lock_taken); /* nl_table locking explained: * Lookup and traversal are protected with an RCU read-side lock. Insertion @@ -1987,7 +1987,7 @@ static int netlink_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, if (READ_ONCE(nlk->cb_running) && atomic_read(&sk->sk_rmem_alloc) <= sk->sk_rcvbuf / 2) { - ret = netlink_dump(sk); + ret = netlink_dump(sk, false); if (ret) { WRITE_ONCE(sk->sk_err, -ret); sk_error_report(sk); @@ -2196,7 +2196,7 @@ static int netlink_dump_done(struct netlink_sock *nlk, struct sk_buff *skb, return 0; } -static int netlink_dump(struct sock *sk) +static int netlink_dump(struct sock *sk, bool lock_taken) { struct netlink_sock *nlk = nlk_sk(sk); struct netlink_ext_ack extack = {}; @@ -2208,7 +2208,8 @@ static int netlink_dump(struct sock *sk) int alloc_min_size; int alloc_size; - mutex_lock(nlk->cb_mutex); + if (!lock_taken) + mutex_lock(nlk->cb_mutex); if (!nlk->cb_running) { err = -EINVAL; goto errout_skb; @@ -2365,9 +2366,7 @@ int __netlink_dump_start(struct sock *ssk, struct sk_buff *skb, WRITE_ONCE(nlk->cb_running, true); nlk->dump_done_errno = INT_MAX; - mutex_unlock(nlk->cb_mutex); - - ret = netlink_dump(sk); + ret = netlink_dump(sk, true); sock_put(sk);