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Subject[27/48] nfs: fix regression in handling of context= option in NFSv4
3.1-stable review patch.  If anyone has any objections, please let me know.

------------------
From: Jeff Layton <jlayton@redhat.com>

commit 8a0d551a59ac92d8ff048d6cb29d3a02073e81e8 upstream.

Setting the security context of a NFSv4 mount via the context= mount
option is currently broken. The NFSv4 codepath allocates a parsed
options struct, and then parses the mount options to fill it. It
eventually calls nfs4_remote_mount which calls security_init_mnt_opts.
That clobbers the lsm_opts struct that was populated earlier. This bug
also looks like it causes a small memory leak on each v4 mount where
context= is used.

Fix this by moving the initialization of the lsm_opts into
nfs_alloc_parsed_mount_data. Also, add a destructor for
nfs_parsed_mount_data to make it easier to free all of the allocations
hanging off of it, and to ensure that the security_free_mnt_opts is
called whenever security_init_mnt_opts is.

I believe this regression was introduced quite some time ago, probably
by commit c02d7adf.

Signed-off-by: Jeff Layton <jlayton@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
fs/nfs/super.c | 43 +++++++++++++++++++------------------------
1 file changed, 19 insertions(+), 24 deletions(-)
--- a/fs/nfs/super.c
+++ b/fs/nfs/super.c
@@ -904,10 +904,24 @@ static struct nfs_parsed_mount_data *nfs
data->auth_flavor_len = 1;
data->version = version;
data->minorversion = 0;
+ security_init_mnt_opts(&data->lsm_opts);
}
return data;
}

+static void nfs_free_parsed_mount_data(struct nfs_parsed_mount_data *data)
+{
+ if (data) {
+ kfree(data->client_address);
+ kfree(data->mount_server.hostname);
+ kfree(data->nfs_server.export_path);
+ kfree(data->nfs_server.hostname);
+ kfree(data->fscache_uniq);
+ security_free_mnt_opts(&data->lsm_opts);
+ kfree(data);
+ }
+}
+
/*
* Sanity-check a server address provided by the mount command.
*
@@ -2215,9 +2229,7 @@ static struct dentry *nfs_fs_mount(struc
data = nfs_alloc_parsed_mount_data(NFS_DEFAULT_VERSION);
mntfh = nfs_alloc_fhandle();
if (data == NULL || mntfh == NULL)
- goto out_free_fh;
-
- security_init_mnt_opts(&data->lsm_opts);
+ goto out;

/* Validate the mount data */
error = nfs_validate_mount_data(raw_data, data, mntfh, dev_name);
@@ -2229,8 +2241,6 @@ static struct dentry *nfs_fs_mount(struc
#ifdef CONFIG_NFS_V4
if (data->version == 4) {
mntroot = nfs4_try_mount(flags, dev_name, data);
- kfree(data->client_address);
- kfree(data->nfs_server.export_path);
goto out;
}
#endif /* CONFIG_NFS_V4 */
@@ -2285,13 +2295,8 @@ static struct dentry *nfs_fs_mount(struc
s->s_flags |= MS_ACTIVE;

out:
- kfree(data->nfs_server.hostname);
- kfree(data->mount_server.hostname);
- kfree(data->fscache_uniq);
- security_free_mnt_opts(&data->lsm_opts);
-out_free_fh:
+ nfs_free_parsed_mount_data(data);
nfs_free_fhandle(mntfh);
- kfree(data);
return mntroot;

out_err_nosb:
@@ -2618,9 +2623,7 @@ nfs4_remote_mount(struct file_system_typ

mntfh = nfs_alloc_fhandle();
if (data == NULL || mntfh == NULL)
- goto out_free_fh;
-
- security_init_mnt_opts(&data->lsm_opts);
+ goto out;

/* Get a volume representation */
server = nfs4_create_server(data, mntfh);
@@ -2672,13 +2675,10 @@ nfs4_remote_mount(struct file_system_typ

s->s_flags |= MS_ACTIVE;

- security_free_mnt_opts(&data->lsm_opts);
nfs_free_fhandle(mntfh);
return mntroot;

out:
- security_free_mnt_opts(&data->lsm_opts);
-out_free_fh:
nfs_free_fhandle(mntfh);
return ERR_PTR(error);

@@ -2858,7 +2858,7 @@ static struct dentry *nfs4_mount(struct

data = nfs_alloc_parsed_mount_data(4);
if (data == NULL)
- goto out_free_data;
+ goto out;

/* Validate the mount data */
error = nfs4_validate_mount_data(raw_data, data, dev_name);
@@ -2872,12 +2872,7 @@ static struct dentry *nfs4_mount(struct
error = PTR_ERR(res);

out:
- kfree(data->client_address);
- kfree(data->nfs_server.export_path);
- kfree(data->nfs_server.hostname);
- kfree(data->fscache_uniq);
-out_free_data:
- kfree(data);
+ nfs_free_parsed_mount_data(data);
dprintk("<-- nfs4_mount() = %d%s\n", error,
error != 0 ? " [error]" : "");
return res;



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