Re: Kernel update 3.5.7 -> 3.6.3 breaks NFS4

["J. Bruce Fields" <bfields@fieldses.org>]

On Tue, Nov 13, 2012 at 07:58:15PM -0500, J. Bruce Fields wrote:
> On Tue, Nov 13, 2012 at 05:40:05PM -0500, J. Bruce Fields wrote:
> > On Mon, Nov 12, 2012 at 10:17:17AM +0100, Sven Geggus wrote:
> > > J. Bruce Fields schrieb am Samstag, den 10. November um 00:24 Uhr:
> > > 
> > > OK, back at work and here is what I get:
> > > 
> > > > Restart the server, start strace, then try the mount, let it hang a few
> > > > seconds just to make sure you got anything interesting, then kill strace
> > > > and send the output.
> > > 
> > > OK, back at work and here is what I get...
> > > 
> > > read(3, "nfsd 10.1.7.30\n", 2048)       = 15
> > > close(15)                               = 0
> > > open("/var/lib/nfs/etab", O_RDONLY)     = 15
> > > close(15)                               = 0
> > > close(15)                               = 0
> > > write(3, "nfsd 10.1.7.30 1352710828 * \n", 29) = 29
> > > read(4, "4294967295\n", 2048)           = 11
> > > close(16)                               = 0
> > > close(15)                               = 0
> > > read(15,
> > > "\2\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\377\377\377\377\377\377\377\377\0\0\0\0\0\0\0\0\0\0\0\0",
> > > 36) = 36
> > > close(15)                               = 0
> > > write(4, "4294967295 1352710828 0 \n", 25) = -1 EINVAL (Invalid argument)
> > 
> > I suspect that error's coming from
> > net/sunrpc/svcauth_unix.c:unix_gid_parse().
> > 
> > > 4294967295 is UINT_MAX and this place is where it behaves differently on a good
> > > kernel where the write call will succeed:
> > > 
> > > write(4, "4294967295 1352710828 0 \n", 25) = 25
> > > 
> > > Sven
> > > 
> > > P.S.: Your patched svcauth_gss.c will give me an "access denied by server"
> > > while mounting instead of the infinite delay:
> > >  ~/ # mount -t nfs4 -o sec=krb5 testsrv:/storage /mnt/
> > > mount.nfs4: access denied by server while mounting testsrv:/storage
> > 
> > So, looks like the same get_int problem exists in several other places.
> > Could you try the following instead of the previous patch?  I think I
> > got them all this time....
> 
> Oh, cripes, but this isn't good enough--svcgssd actually passes down -1
> id's.  Ugh--I'll take a closer look tomorrow.

Yeah, for backwards compatibility reasons we probably don't want to
reject either -1 or 4294967295.

So I'm inclined to revert unless Eldad has a better idea.

--b.

commit 664f26313a738f539a32c4eadd5351905e301bf2
Author: J. Bruce Fields <bfields@redhat.com>
Date:   Fri Nov 9 15:16:02 2012 -0500

    svcrpc: fix parsing of uids and gids in gss contexts
    
    bbf43dc888833ac0539e437dbaeb28bfd4fbab9f "sunrpc/cache.h: replace
    simple_strtoul" introduced new range-checking which could cause get_int
    to fail if given an unsigned integer too large to represent as an int.
    
    Symptoms were hangs on krb5 mounts after upgrading an NFS server.
    
    Cc: Eldad Zack <eldad@fogrefinery.com>
    Reported-by: Sven Geggus <lists@fuchsschwanzdomain.de>
    Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/export.c b/fs/nfsd/export.c
index a3946cf..8481961 100644
--- a/fs/nfsd/export.c
+++ b/fs/nfsd/export.c
@@ -491,7 +491,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
 	int err;
 	struct auth_domain *dom = NULL;
 	struct svc_export exp = {}, *expp;
-	int an_int;
+	unsigned int an_int;
 
 	if (mesg[mlen-1] != '\n')
 		return -EINVAL;
@@ -531,7 +531,7 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
 		goto out3;
 
 	/* flags */
-	err = get_int(&mesg, &an_int);
+	err = get_uint(&mesg, &an_int);
 	if (err == -ENOENT) {
 		err = 0;
 		set_bit(CACHE_NEGATIVE, &exp.h.flags);
@@ -541,19 +541,19 @@ static int svc_export_parse(struct cache_detail *cd, char *mesg, int mlen)
 		exp.ex_flags= an_int;
 	
 		/* anon uid */
-		err = get_int(&mesg, &an_int);
+		err = get_uint(&mesg, &an_int);
 		if (err)
 			goto out3;
 		exp.ex_anon_uid= an_int;
 
 		/* anon gid */
-		err = get_int(&mesg, &an_int);
+		err = get_uint(&mesg, &an_int);
 		if (err)
 			goto out3;
 		exp.ex_anon_gid= an_int;
 
 		/* fsid */
-		err = get_int(&mesg, &an_int);
+		err = get_uint(&mesg, &an_int);
 		if (err)
 			goto out3;
 		exp.ex_fsid = an_int;
diff --git a/fs/nfsd/nfs4idmap.c b/fs/nfsd/nfs4idmap.c
index a1f10c0..e2c9317 100644
--- a/fs/nfsd/nfs4idmap.c
+++ b/fs/nfsd/nfs4idmap.c
@@ -415,7 +415,7 @@ nametoid_parse(struct cache_detail *cd, char *buf, int buflen)
 		goto out;
 
 	/* ID */
-	error = get_int(&buf, &ent.id);
+	error = get_uint(&buf, &ent.id);
 	if (error == -EINVAL)
 		goto out;
 	if (error == -ENOENT)
diff --git a/net/sunrpc/auth_gss/svcauth_gss.c b/net/sunrpc/auth_gss/svcauth_gss.c
index 73e9573..243d180 100644
--- a/net/sunrpc/auth_gss/svcauth_gss.c
+++ b/net/sunrpc/auth_gss/svcauth_gss.c
@@ -444,7 +444,7 @@ static int rsc_parse(struct cache_detail *cd,
 		goto out;
 
 	/* uid, or NEGATIVE */
-	rv = get_int(&mesg, &rsci.cred.cr_uid);
+	rv = get_uint(&mesg, &rsci.cred.cr_uid);
 	if (rv == -EINVAL)
 		goto out;
 	if (rv == -ENOENT)
@@ -453,7 +453,7 @@ static int rsc_parse(struct cache_detail *cd,
 		int N, i;
 
 		/* gid */
-		if (get_int(&mesg, &rsci.cred.cr_gid))
+		if (get_uint(&mesg, &rsci.cred.cr_gid))
 			goto out;
 
 		/* number of additional gid's */
@@ -469,7 +469,7 @@ static int rsc_parse(struct cache_detail *cd,
 		for (i=0; i<N; i++) {
 			gid_t gid;
 			kgid_t kgid;
-			if (get_int(&mesg, &gid))
+			if (get_uint(&mesg, &gid))
 				goto out;
 			kgid = make_kgid(&init_user_ns, gid);
 			if (!gid_valid(kgid))
diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index 4d01292..5d7020a 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -493,7 +493,7 @@ static int unix_gid_parse(struct cache_detail *cd,
 		return -EINVAL;
 	mesg[mlen-1] = 0;
 
-	rv = get_int(&mesg, &uid);
+	rv = get_uint(&mesg, &uid);
 	if (rv)
 		return -EINVAL;
 	ug.uid = uid;
@@ -513,7 +513,7 @@ static int unix_gid_parse(struct cache_detail *cd,
 	for (i = 0 ; i < gids ; i++) {
 		int gid;
 		kgid_t kgid;
-		rv = get_int(&mesg, &gid);
+		rv = get_uint(&mesg, &gid);
 		err = -EINVAL;
 		if (rv)
 			goto out;