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 1B92B2F9DA1; Fri, 4 Sep 2026 05:51:25 +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=1788501086; cv=none; b=i65z7Ch18iCpSt0iVSsrq8tHz9Gh4+ORTN9eMmPw3MM2rsTo/EiSFzfNSIgKe1FfoSVMQqCyzzF/xaRef1kg84mpzLDT5pRIWi+XybO12VaV3lvmeKSqHtatngndIt0BsvQwdWHyFkDrai22LAnm0H8xrAtkzo9VeuUXFwIl2Us= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788501086; c=relaxed/simple; bh=Ac2R8kwmdxgQoxCj7Tcw3oxxBMriXUETXdLyr0obQpM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=Oi2K9xL3yzRlbkczOMo2YriZrQJO6f+Zq2WgGcPmDAJEHqW6C7gsFnjHInqLIlBTUNRCdnzX2q/vzPv/KRTMOavxuWqe7A9vH/da159a5ZwMJoatHhZp+ItzahZd+prV7NbGpgybXM6EzFdT/yDczqpx1AdLelX+Q7rEB5EX/Uk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=gMKywqRc; 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="gMKywqRc" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6D3FD1F00A3D; Fri, 4 Sep 2026 05:51:24 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1788501085; bh=zl2FvrQ3I653hDEjF+syMWMYh0OH/vzgqFo0cOFg5Rc=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=gMKywqRcIn2uAuCCC7AC48sRk7YAqPMXRs2D7i2rmXMuUA1OEH69PhGMgjvlYQFxA RAauFgwoZ+tIKl0vbWIc6pJYCtFdFhp96vPhAq0Ntorv/3stgV9x3aV6a+2dGxpPvB t38fN8Yxn+XZgutmEj00myNeB3oV18d3QpkAT5oo= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Yuan Tan , Xin Liu , Ren Wei , Luxiao Xu , Trond Myklebust Subject: [PATCH 6.18 284/552] sunrpc: fix use-after-free in __rpc_clnt_handle_event and __rpc_clnt_remove_pipedir Date: Fri, 4 Sep 2026 06:57:21 +0200 Message-ID: <20260904045756.399713079@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260904045747.813364717@linuxfoundation.org> References: <20260904045747.813364717@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 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Luxiao Xu commit 932a8cf6abb2b2f8677b79153a823108d8861fe2 upstream. Normal client creation goes through rpc_setup_pipedir(), which records clnt->pipefs_sb, but the mount-event path in __rpc_clnt_handle_event() calls rpc_setup_pipedir_sb() directly and never refreshes that field. The umount path also removes the directory without clearing clnt->pipefs_sb. After a late pipefs mount or any remount, rpc_clnt_remove_pipedir() compares the current superblock against a stale pipefs_sb pointer and skips cleanup, leaving pipefs dentries whose inode private data still points at a freed rpc_clnt, leading to a potential use-after-free during subsequent rpc_info_open() or rpc_show_info() calls. Fix this by properly updating clnt->pipefs_sb upon mount events and clearing it during unmount or failure paths. Fixes: bfca5fb4e97c ("SUNRPC: Fix RPC client cleaned up the freed pipefs dentries") Cc: stable@vger.kernel.org Reported-by: Yuan Tan Reported-by: Xin Liu Reviewed-by: Ren Wei Assisted-by: Codex:gpt-5.4 Signed-off-by: Luxiao Xu Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman --- net/sunrpc/clnt.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -96,7 +96,10 @@ static void rpc_unregister_client(struct static void __rpc_clnt_remove_pipedir(struct rpc_clnt *clnt) { - rpc_remove_client_dir(clnt); + if (clnt->pipefs_sb) { + rpc_remove_client_dir(clnt); + clnt->pipefs_sb = NULL; + } } static void rpc_clnt_remove_pipedir(struct rpc_clnt *clnt) @@ -177,19 +180,28 @@ static int rpc_clnt_skip_event(struct rp } static int __rpc_clnt_handle_event(struct rpc_clnt *clnt, unsigned long event, - struct super_block *sb) + struct super_block *sb) { + int err = 0; + switch (event) { case RPC_PIPEFS_MOUNT: - return rpc_setup_pipedir_sb(sb, clnt); + clnt->pipefs_sb = sb; + err = rpc_setup_pipedir_sb(sb, clnt); + if (err) + clnt->pipefs_sb = NULL; + break; case RPC_PIPEFS_UMOUNT: - __rpc_clnt_remove_pipedir(clnt); + if (clnt->pipefs_sb == sb) { + __rpc_clnt_remove_pipedir(clnt); + clnt->pipefs_sb = NULL; + } break; default: printk(KERN_ERR "%s: unknown event: %ld\n", __func__, event); return -ENOTSUPP; } - return 0; + return err; } static int __rpc_pipefs_event(struct rpc_clnt *clnt, unsigned long event,