From patchwork Wed Dec 5 22:31:40 2012 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit Subject: [3.5.y.z, extended, stable] Patch "NFS: fix bug in legacy DNS resolver." has been added to staging queue From: Herton Ronaldo Krzesinski X-Patchwork-Id: 204018 Message-Id: <1354746700-22477-1-git-send-email-herton.krzesinski@canonical.com> To: NeilBrown Cc: kernel-team@lists.ubuntu.com, Chuck Lever , Trond Myklebust Date: Wed, 5 Dec 2012 20:31:40 -0200 This is a note to let you know that I have just added a patch titled NFS: fix bug in legacy DNS resolver. to the linux-3.5.y-queue branch of the 3.5.y.z extended stable tree which can be found at: http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.5.y-queue If you, or anyone else, feels it should not be added to this tree, please reply to this email. For more information about the 3.5.y.z tree, see https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable Thanks. -Herton ------ >From ab7c3e03e68f8092dd304f954ef39b125c69180b Mon Sep 17 00:00:00 2001 From: NeilBrown Date: Wed, 31 Oct 2012 12:16:01 +1100 Subject: [PATCH] NFS: fix bug in legacy DNS resolver. X-Extended-Stable: 3.5 commit 8d96b10639fb402357b75b055b1e82a65ff95050 upstream. The DNS resolver's use of the sunrpc cache involves a 'ttl' number (relative) rather that a timeout (absolute). This confused me when I wrote commit c5b29f885afe890f953f7f23424045cdad31d3e4 "sunrpc: use seconds since boot in expiry cache" and I managed to break it. The effect is that any TTL is interpreted as 0, and nothing useful gets into the cache. This patch removes the use of get_expiry() - which really expects an expiry time - and uses get_uint() instead, treating the int correctly as a ttl. This fixes a regression that has been present since 2.6.37, causing certain NFS accesses in certain environments to incorrectly fail. Reported-by: Chuck Lever Tested-by: Chuck Lever Signed-off-by: NeilBrown Signed-off-by: Trond Myklebust Signed-off-by: Herton Ronaldo Krzesinski --- fs/nfs/dns_resolve.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) -- 1.7.9.5 diff --git a/fs/nfs/dns_resolve.c b/fs/nfs/dns_resolve.c index b3924b8..786cd65 100644 --- a/fs/nfs/dns_resolve.c +++ b/fs/nfs/dns_resolve.c @@ -214,7 +214,7 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) { char buf1[NFS_DNS_HOSTNAME_MAXLEN+1]; struct nfs_dns_ent key, *item; - unsigned long ttl; + unsigned int ttl; ssize_t len; int ret = -EINVAL; @@ -237,7 +237,8 @@ static int nfs_dns_parse(struct cache_detail *cd, char *buf, int buflen) key.namelen = len; memset(&key.h, 0, sizeof(key.h)); - ttl = get_expiry(&buf); + if (get_uint(&buf, &ttl) < 0) + goto out; if (ttl == 0) goto out; key.h.expiry_time = ttl + seconds_since_boot();