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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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