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 106AF59B67F for ; Tue, 8 Sep 2026 22:37:19 +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=1788907045; cv=none; b=NqivEPDQsrLoueyC4nKxFewDok/SOT4d5KnbRyerDtENnCe7Hw9b0LaYKpGUpHd1YFsAHI5aimp9/LE1r81dkH62YQpDcixGyPPk7zkNuin6+GdZHSHgmBDKYl3KWn0QIw5ob2iTAIN8C9XkUbIztJl7WfZ41q702avmtHoM4oY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1788907045; c=relaxed/simple; bh=JBinirQ4BlZie4T+MGLSbSHr2czA6ABsp6qalSnqPlo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=EsqpgP485KMJfPPWXwBX3PMONrHTq60HZVqsxZc5n9wF8nG5nof27mMhAPuxm+MyH5gIMxC6iD+YcvqlycNuoBtCsskKqnkV+4l+vMw262HwvyMVYayJnsAjnO5g/P88+sDiQ08idTgcGn1fXgEsH/cQ7tFAquPmVbY7hWfWJTI= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=UcoLwbJJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="UcoLwbJJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C3D7A1F00AC4; Tue, 8 Sep 2026 22:37:18 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1788907039; bh=5aR0+ERQmcfFel8dQRFHC5RWnjO/DVt9FZpyKYpIT40=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UcoLwbJJgG2QsB6EDwOwhdQ9UfapR2KYB7roIxAL+0SkHG2XCIVweZPGssQHk5PHZ f5KcGazPEWNOpqmqujlkDy1bswimxrOlWLLAaT1Y+SLQh9HKhEPz9/mXSkGCZOP+GJ igVzp+7tnVkTSXa5VCIIQXPrnB/Tr6ehXbix6tmcZV4hasRpd6eYZt1ytLlAZMiosS nxeAhloQt1yie+qeZGzfQzmXgq1BjJqUwM3cgJbdsK2WUu4Tz0gskQOr/d+hD8RrCq YVNP2z/6u8TJx1j3ee172J2f9KUflW1nD6wewDbc8604fCD2lsBVmgrdugkyYCAN8y UKED15JNzDLdQ== From: Sasha Levin To: stable@vger.kernel.org Cc: Luxiao Xu , Yuan Tan , Xin Liu , Ren Wei , Trond Myklebust , Sasha Levin Subject: [PATCH 6.12.y 4/4] sunrpc: fix use-after-free in __rpc_clnt_handle_event and __rpc_clnt_remove_pipedir Date: Tue, 8 Sep 2026 18:37:15 -0400 Message-ID: <20260908223715.507115-4-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260908223715.507115-1-sashal@kernel.org> References: <2026090317-curled-track-17d1@gregkh> <20260908223715.507115-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Luxiao Xu [ Upstream commit 932a8cf6abb2b2f8677b79153a823108d8861fe2 ] 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: Sasha Levin --- net/sunrpc/clnt.c | 22 +++++++++++++++++----- 1 file changed, 17 insertions(+), 5 deletions(-) diff --git a/net/sunrpc/clnt.c b/net/sunrpc/clnt.c index 1eca77bd03930..f23a17ebd0391 100644 --- a/net/sunrpc/clnt.c +++ b/net/sunrpc/clnt.c @@ -96,7 +96,10 @@ static void rpc_unregister_client(struct rpc_clnt *clnt) 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 rpc_clnt *clnt, unsigned long event) } 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, -- 2.53.0