linux-kernel - [PATCH 3.16 99/99] sunrpc: expiry_time should be seconds not timeval

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Date:   Wed, 20 May 2020 15:15:07 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, Denis Kirjanov <kda@...ux-powerpc.org>,
        "J. Bruce Fields" <bfields@...hat.com>,
        "Roberto Bergantinos Corpas" <rbergant@...hat.com>,
        "Frank Sorenson" <sorenson@...hat.com>
Subject: [PATCH 3.16 99/99] sunrpc: expiry_time should be seconds not timeval

3.16.84-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Roberto Bergantinos Corpas <rbergant@...hat.com>

commit 3d96208c30f84d6edf9ab4fac813306ac0d20c10 upstream.

When upcalling gssproxy, cache_head.expiry_time is set as a
timeval, not seconds since boot. As such, RPC cache expiry
logic will not clean expired objects created under
auth.rpcsec.context cache.

This has proven to cause kernel memory leaks on field. Using
64 bit variants of getboottime/timespec

Expiration times have worked this way since 2010's c5b29f885afe "sunrpc:
use seconds since boot in expiry cache".  The gssproxy code introduced
in 2012 added gss_proxy_save_rsc and introduced the bug.  That's a while
for this to lurk, but it required a bit of an extreme case to make it
obvious.

Signed-off-by: Roberto Bergantinos Corpas <rbergant@...hat.com>
Fixes: 030d794bf498 "SUNRPC: Use gssproxy upcall for server..."
Tested-By: Frank Sorenson <sorenson@...hat.com>
Signed-off-by: J. Bruce Fields <bfields@...hat.com>
[bwh: Backported to 3.16: Use struct timespec and getboottime()]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 net/sunrpc/auth_gss/svcauth_gss.c | 4 ++++
 1 file changed, 4 insertions(+)

--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -1171,6 +1171,7 @@ static int gss_proxy_save_rsc(struct cac
 		dprintk("RPC:       No creds found!\n");
 		goto out;
 	} else {
+		struct timespec boot;

 		/* steal creds */
 		rsci.cred = ud->creds;
@@ -1191,6 +1192,9 @@ static int gss_proxy_save_rsc(struct cac
 						&expiry, GFP_KERNEL);
 		if (status)
 			goto out;
+
+		getboottime(&boot);
+		expiry -= boot.tv_sec;
 	}

 	rsci.h.expiry_time = expiry;