From 8a0d551a59ac92d8ff048d6cb29d3a02073e81e8 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Tue, 20 Dec 2011 06:57:45 -0500 Subject: [PATCH] nfs: fix regression in handling of context= option in NFSv4 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. Cc: stable@vger.kernel.org Signed-off-by: Jeff Layton Signed-off-by: Trond Myklebust --- fs/nfs/super.c | 43 +++++++++++++++++++------------------------ 1 file changed, 19 insertions(+), 24 deletions(-) diff --git a/fs/nfs/super.c b/fs/nfs/super.c index 134777406ee3..3ada13c9986a 100644 --- a/fs/nfs/super.c +++ b/fs/nfs/super.c @@ -909,10 +909,24 @@ static struct nfs_parsed_mount_data *nfs_alloc_parsed_mount_data(unsigned int ve 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. * @@ -2220,9 +2234,7 @@ static struct dentry *nfs_fs_mount(struct file_system_type *fs_type, 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); @@ -2234,8 +2246,6 @@ static struct dentry *nfs_fs_mount(struct file_system_type *fs_type, #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 */ @@ -2290,13 +2300,8 @@ static struct dentry *nfs_fs_mount(struct file_system_type *fs_type, 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: @@ -2623,9 +2628,7 @@ nfs4_remote_mount(struct file_system_type *fs_type, int flags, 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); @@ -2677,13 +2680,10 @@ nfs4_remote_mount(struct file_system_type *fs_type, int flags, 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); @@ -2838,7 +2838,7 @@ static struct dentry *nfs4_mount(struct file_system_type *fs_type, 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); @@ -2852,12 +2852,7 @@ static struct dentry *nfs4_mount(struct file_system_type *fs_type, 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;