From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 DAB788489; Sat, 30 Dec 2023 12:03:07 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="mmil2nYA" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 648B2C433C8; Sat, 30 Dec 2023 12:03:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1703937787; bh=UIfzTt4MHUGLq7PCIeCXpuy+d2zUI9fOnuFxct/dH8k=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=mmil2nYAFECykGFDj/InICl11kKViuebksBgZ9vh9/l0/vL9Ipz+fjJnE5qxmv+f6 YFREAyR9kKzH5nFVDFQ923stjIElqJhMQRAT0k+pv9lLgu9LuhzQ1EO7+/9tG0Xu3P LWeCgLTd4QVzgbHgIhESyqp5H0A7fG28du/ij4cA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Markus Suvanto , David Howells , Marc Dionne , linux-afs@lists.infradead.org, Sasha Levin Subject: [PATCH 6.6 063/156] afs: Fix dynamic root lookup DNS check Date: Sat, 30 Dec 2023 11:58:37 +0000 Message-ID: <20231230115814.405414596@linuxfoundation.org> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20231230115812.333117904@linuxfoundation.org> References: <20231230115812.333117904@linuxfoundation.org> User-Agent: quilt/0.67 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Howells [ Upstream commit 74cef6872ceaefb5b6c5c60641371ea28702d358 ] In the afs dynamic root directory, the ->lookup() function does a DNS check on the cell being asked for and if the DNS upcall reports an error it will report an error back to userspace (typically ENOENT). However, if a failed DNS upcall returns a new-style result, it will return a valid result, with the status field set appropriately to indicate the type of failure - and in that case, dns_query() doesn't return an error and we let stat() complete with no error - which can cause confusion in userspace as subsequent calls that trigger d_automount then fail with ENOENT. Fix this by checking the status result from a valid dns_query() and returning an error if it indicates a failure. Fixes: bbb4c4323a4d ("dns: Allow the dns resolver to retrieve a server set") Reported-by: Markus Suvanto Closes: https://bugzilla.kernel.org/show_bug.cgi?id=216637 Signed-off-by: David Howells Tested-by: Markus Suvanto cc: Marc Dionne cc: linux-afs@lists.infradead.org Signed-off-by: Sasha Levin --- fs/afs/dynroot.c | 18 ++++++++++++++++-- 1 file changed, 16 insertions(+), 2 deletions(-) diff --git a/fs/afs/dynroot.c b/fs/afs/dynroot.c index cec7d8e5ad0c9..10905a53d5b27 100644 --- a/fs/afs/dynroot.c +++ b/fs/afs/dynroot.c @@ -114,6 +114,7 @@ static int afs_probe_cell_name(struct dentry *dentry) struct afs_net *net = afs_d2net(dentry); const char *name = dentry->d_name.name; size_t len = dentry->d_name.len; + char *result = NULL; int ret; /* Names prefixed with a dot are R/W mounts. */ @@ -131,9 +132,22 @@ static int afs_probe_cell_name(struct dentry *dentry) } ret = dns_query(net->net, "afsdb", name, len, "srv=1", - NULL, NULL, false); - if (ret == -ENODATA || ret == -ENOKEY) + &result, NULL, false); + if (ret == -ENODATA || ret == -ENOKEY || ret == 0) ret = -ENOENT; + if (ret > 0 && ret >= sizeof(struct dns_server_list_v1_header)) { + struct dns_server_list_v1_header *v1 = (void *)result; + + if (v1->hdr.zero == 0 && + v1->hdr.content == DNS_PAYLOAD_IS_SERVER_LIST && + v1->hdr.version == 1 && + (v1->status != DNS_LOOKUP_GOOD && + v1->status != DNS_LOOKUP_GOOD_WITH_BAD)) + return -ENOENT; + + } + + kfree(result); return ret; } -- 2.43.0