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From: NeilBrown <neilb@suse.de>
To: "J. Bruce Fields" <bfields@fieldses.org>,
	Chuck Lever <chuck.lever@oracle.com>,
	kircherlike@outlook.com,
	Stephen Hemminger <stephen@networkplumber.org>
Cc: linux-nfs@vger.kernel.org
Subject: [PATCH 2/3] sunrpc: svcauth_gss_register_pseudoflavor must reject duplicate registrations.
Date: Fri, 22 May 2020 12:01:33 +1000
Message-ID: <159011289297.29107.15128425916228317497.stgit@noble> (raw)
In-Reply-To: <159011265914.29107.13764997801950546826.stgit@noble>

There is no valid case for supporting duplicate pseudoflavor
registrations.
Currently the silent acceptance of such registrations is hiding a bug.
The rpcsec_gss_krb5 module registers 2 flavours but does not unregister
them, so if you load, unload, reload the module, it will happily
continue to use the old registration which now has pointers to the
memory were the module was originally loaded.  This could lead to
unexpected results.

So disallow duplicate registrations.

Link: https://bugzilla.kernel.org/show_bug.cgi?id=206651
Cc: stable@vger.kernel.org (v2.6.12+)
Signed-off-by: NeilBrown <neilb@suse.de>
---
 net/sunrpc/auth_gss/svcauth_gss.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 50d93c49ef1a..49bb346a6215 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -826,9 +826,11 @@ svcauth_gss_register_pseudoflavor(u32 pseudoflavor, char * name)
 	new->h.flavour = &svcauthops_gss;
 	new->pseudoflavor = pseudoflavor;
 
-	stat = 0;
 	test = auth_domain_lookup(name, &new->h);
-	if (test != &new->h) { /* Duplicate registration */
+	if (test != &new->h) {
+		pr_warn("svc: duplicate registration of gss pseudo flavour %s.\n",
+			name);
+		stat = -EADDRINUSE;
 		auth_domain_put(test);
 		kfree(new->h.name);
 		goto out_free_dom;



  parent reply index

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-22  2:01 [PATCH 0/3 - V2] SUNRPC/svc: fix gss flavour registration problems NeilBrown
2020-05-22  2:01 ` [PATCH 1/3] sunrpc: check that domain table is empty at module unload NeilBrown
2020-05-22  2:01 ` [PATCH 3/3] sunrpc: clean up properly in gss_mech_unregister() NeilBrown
2020-05-26  0:23   ` Sasha Levin
2020-05-26  0:50     ` NeilBrown
2020-05-22  2:01 ` NeilBrown [this message]
  -- strict thread matches above, loose matches on Subject: below --
2020-05-21  3:21 [PATCH 0/3] SUNRPC/svc: fix gss flavour registration problems NeilBrown
2020-05-21  3:21 ` [PATCH 2/3] sunrpc: svcauth_gss_register_pseudoflavor must reject duplicate registrations NeilBrown

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