On Mon, 03 Mar 2008 14:42:52 -0500
Eric Paris <eparis@xxxxxxxxxx> wrote:
> In the current code (approved by SELinux and NFS people in 2004) SELinux
> tries to understand NFS's binary mount data. This blows up in the face
> of things like nohide mounts which don't use struct nfs_mount_data and I
> assume just looking at the code that things don't work since NFS moved
> to using nfs_parsed_mount_data as its default binary mount data blob.
>
> This patch creates a new LSM interfaces allowing NFS to hand argument
> processing over to the LSM and get back a binary blob the LSM
> understands for later user. There is no specific SELinux knowledge
> inside NFS and no NFS information left inside SELinux. NFS now passes
> either strings or the LSM data blob into the LSM and lets the LSM do its
> own work. This means that all LSM mount options are supported by NFS
> when it uses the text userspace interface.
>
> This patch makes NFS use the new LSM hooks security_sb_set_mnt_opts()
> and security_sb_clone_mnt_opts() inside the ->get_sb() calls so that
> security options are set explicitly by NFS before the generic NFS
> settings used by non binary mount data fs's. The only sorta
> 'selinux-ism' in this patch is for the NFS binary mount data interface
> (which must keep working to stop any regressions) to reattach "context="
> to the data. This part of the string will have been removed by the
> older mount.nfs userspace parser. That little nugget is well commented
> and wrapper in CONFIG_SECURITY_SELINUX.
>
> We need this for 2.6.25 since at the moment SELinux (and SMACK) + nohide
> mounts cause security_sb_copy_mount_data() to copy one page of mount
> data starting at the struct nfs_clone_mount_data on the stack. If the
> stack doesn't span 2 pages we run off the end of the stack and hit a
> page fault BUG(). This also solves the regression in functionality
> since all SELinux support was broken with the switch to
> nfs_parsed_mount_data.
>
> Signed-off-by: Eric Paris <eparis@xxxxxxxxxx>
>
> ---
>
> This patch was tested with NFSv3 mounts and solves all of the
> regressions that have been introduced in the NFS code. It supports both
> the binary interface and text options without pushing LSM specific
> parsing into the FS. It doesn't introduce the new LSM constructs
> necessary to show these mount options in /proc/mounts suggested by
> Miklos Szeredi but that will be coming in 2.6.26 (it's not a regression
> or bug fix). I also do not have the proper security_sb_set_mnt_opts()
> call in nfs4_get_sb due to a lack of a testing environment, but will add
> that in 2.6.26 as well. SELinux + NFSv4 have never had context mount
> options so there is no regression nor loss of functionality.
>
> Would the NFS community like to push all of this through their bug fix
> trees or would they prefer I just push this whole patch up the SELinux
> trees?
>
I like the basic approach -- seems like a clean way to do this. I'm
not sure I know enough about the selinux/security internals to give
that a good review, though I made a quick pass through it. Which brings
me to a somewhat minor nit...
Would it be possible to break this patch up while keeping the tree
cleanly bisectable? Maybe one or more patches that add the new
interfaces and then another separate NFS patch that changes it to use
the new interfaces? Not only would that make this easier to review, but
the separate NFS patch might also help serve as a model for other
filesystems that want to take advantage of the new interfaces.
A couple of comments interspersed below...
> fs/nfs/internal.h | 3 +
> fs/nfs/super.c | 63 ++++++++++++-
> fs/super.c | 4 +-
> include/linux/security.h | 99 +++++++++++++++-----
> security/dummy.c | 23 +++--
> security/security.c | 23 +++--
> security/selinux/hooks.c | 175 +++++++++++++++++++----------------
> security/selinux/include/security.h | 5 +
> security/smack/smack_lsm.c | 9 +--
> 9 files changed, 268 insertions(+), 136 deletions(-)
>
> diff --git a/fs/nfs/internal.h b/fs/nfs/internal.h
> index 0f56196..9319927 100644
> --- a/fs/nfs/internal.h
> +++ b/fs/nfs/internal.h
> @@ -3,6 +3,7 @@
> */
>
> #include <linux/mount.h>
> +#include <linux/security.h>
>
> struct nfs_string;
>
> @@ -57,6 +58,8 @@ struct nfs_parsed_mount_data {
> char *export_path;
> int protocol;
> } nfs_server;
> +
> + struct security_mnt_opts lsm_opts;
> };
>
> /* client.c */
> diff --git a/fs/nfs/super.c b/fs/nfs/super.c
> index 1fb3818..a097adf 100644
> --- a/fs/nfs/super.c
> +++ b/fs/nfs/super.c
> @@ -684,8 +684,9 @@ static void nfs_parse_server_address(char *value,
> static int nfs_parse_mount_options(char *raw,
> struct nfs_parsed_mount_data *mnt)
> {
> - char *p, *string;
> + char *p, *string, *secdata;
> unsigned short port = 0;
> + int rc;
>
> if (!raw) {
> dfprintk(MOUNT, "NFS: mount options string was NULL.\n");
> @@ -693,6 +694,20 @@ static int nfs_parse_mount_options(char *raw,
> }
> dfprintk(MOUNT, "NFS: nfs mount opts='%s'\n", raw);
>
> + secdata = alloc_secdata();
> + if (!secdata)
> + goto out_nomem;
> +
> + rc = security_sb_copy_data(raw, secdata);
> + if (rc)
> + goto out_security_failure;
> +
> + rc = security_sb_parse_opts_str(secdata, &mnt->lsm_opts);
> + if (rc)
> + goto out_security_failure;
> +
> + free_secdata(secdata);
> +
> while ((p = strsep(&raw, ",")) != NULL) {
> substring_t args[MAX_OPT_ARGS];
> int option, token;
> @@ -1042,7 +1057,10 @@ static int nfs_parse_mount_options(char *raw,
> out_nomem:
> printk(KERN_INFO "NFS: not enough memory to parse option\n");
> return 0;
> -
> +out_security_failure:
> + free_secdata(secdata);
> + printk(KERN_INFO "NFS: security options invalid: %d\n", rc);
> + return 0;
> out_unrec_vers:
> printk(KERN_INFO "NFS: unrecognized NFS version number\n");
> return 0;
> @@ -1214,6 +1232,32 @@ static int nfs_validate_mount_data(void *options,
> args->namlen = data->namlen;
> args->bsize = data->bsize;
> args->auth_flavors[0] = data->pseudoflavor;
> +
> + /*
> + * The legacy version 6 binary mount data from userspace has a
> + * field used only to transport selinux information into the
> + * the kernel. To continue to support that functionality we
> + * have a touch of selinux knowledge here in the NFS code. The
> + * userspace code converted context=blah to just blah so we are
> + * converting back to the full string selinux understands.
> + */
> + if (data->context[0]){
> +#ifdef CONFIG_SECURITY_SELINUX
> + int rc;
> + char *opts_str = kmalloc(sizeof(data->context) + 8, GFP_KERNEL);
> + if (!opts_str)
> + return -ENOMEM;
> + strcpy(opts_str, "context=");
> + strcat(opts_str, &data->context[0]);
> + rc = security_sb_parse_opts_str(opts_str, &args->lsm_opts);
> + kfree(opts_str);
> + if (rc)
> + return rc;
> +#else
> + return -EINVAL;
> +#endif
> + }
> +
> break;
> default: {
> unsigned int len;
> @@ -1476,6 +1520,8 @@ static int nfs_get_sb(struct file_system_type *fs_type,
> };
> int error;
>
> + security_init_mnt_opts(&data.lsm_opts);
> +
> /* Validate the mount data */
> error = nfs_validate_mount_data(raw_data, &data, &mntfh, dev_name);
> if (error < 0)
> @@ -1515,6 +1561,10 @@ static int nfs_get_sb(struct file_system_type *fs_type,
> goto error_splat_super;
> }
>
> + error = security_sb_set_mnt_opts(s, &data.lsm_opts);
> + if (error)
> + goto error_splat_root;
> +
> s->s_flags |= MS_ACTIVE;
> mnt->mnt_sb = s;
> mnt->mnt_root = mntroot;
> @@ -1523,12 +1573,15 @@ static int nfs_get_sb(struct file_system_type *fs_type,
> out:
> kfree(data.nfs_server.hostname);
> kfree(data.mount_server.hostname);
> + security_free_mnt_opts(&data.lsm_opts);
> return error;
>
> out_err_nosb:
> nfs_free_server(server);
> goto out;
>
> +error_splat_root:
> + dput(mntroot);
> error_splat_super:
> up_write(&s->s_umount);
> deactivate_super(s);
> @@ -1608,6 +1661,9 @@ static int nfs_xdev_get_sb(struct file_system_type *fs_type, int flags,
> mnt->mnt_sb = s;
> mnt->mnt_root = mntroot;
>
> + /* clone any lsm security options from the parent to the new sb */
> + security_sb_clone_mnt_opts(data->sb, s);
> +
> dprintk("<-- nfs_xdev_get_sb() = 0\n");
> return 0;
>
> @@ -1850,6 +1906,8 @@ static int nfs4_get_sb(struct file_system_type *fs_type,
> };
> int error;
>
> + security_init_mnt_opts(&data.lsm_opts);
> +
> /* Validate the mount data */
> error = nfs4_validate_mount_data(raw_data, &data, dev_name);
> if (error < 0)
> @@ -1898,6 +1956,7 @@ out:
> kfree(data.client_address);
> kfree(data.nfs_server.export_path);
> kfree(data.nfs_server.hostname);
> + security_free_mnt_opts(&data.lsm_opts);
> return error;
>
> out_free:
> diff --git a/fs/super.c b/fs/super.c
> index 88811f6..010446d 100644
> --- a/fs/super.c
> +++ b/fs/super.c
> @@ -870,12 +870,12 @@ vfs_kern_mount(struct file_system_type *type, int flags, const char *name, void
> if (!mnt)
> goto out;
>
> - if (data) {
> + if (data && !(type->fs_flags & FS_BINARY_MOUNTDATA)) {
> secdata = alloc_secdata();
> if (!secdata)
> goto out_mnt;
>
> - error = security_sb_copy_data(type, data, secdata);
> + error = security_sb_copy_data(data, secdata);
> if (error)
> goto out_free_secdata;
> }
> diff --git a/include/linux/security.h b/include/linux/security.h
> index fe52cde..4ca8630 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -34,12 +34,6 @@
> #include <linux/xfrm.h>
> #include <net/flow.h>
>
> -/* only a char in selinux superblock security struct flags */
> -#define FSCONTEXT_MNT 0x01
> -#define CONTEXT_MNT 0x02
> -#define ROOTCONTEXT_MNT 0x04
> -#define DEFCONTEXT_MNT 0x08
> -
> extern unsigned securebits;
>
> struct ctl_table;
> @@ -114,6 +108,32 @@ struct request_sock;
>
> #ifdef CONFIG_SECURITY
>
> +struct security_mnt_opts {
> + char **mnt_opts;
> + int *mnt_opts_flags;
> + int num_mnt_opts;
> +};
> +
> +static inline void security_init_mnt_opts(struct security_mnt_opts *opts)
> +{
> + opts->mnt_opts = NULL;
> + opts->mnt_opts_flags = NULL;
> + opts->num_mnt_opts = 0;
> +}
> +
> +static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
> +{
> + int i;
> + if (opts->mnt_opts)
> + for(i = 0; i < opts->num_mnt_opts; i++)
> + kfree(opts->mnt_opts[i]);
> + kfree(opts->mnt_opts);
> + opts->mnt_opts = NULL;
> + kfree(opts->mnt_opts_flags);
> + opts->mnt_opts_flags = NULL;
> + opts->num_mnt_opts = 0;
> +}
> +
> /**
> * struct security_operations - main security structure
> *
> @@ -262,19 +282,19 @@ struct request_sock;
> * @sb_get_mnt_opts:
> * Get the security relevant mount options used for a superblock
> * @sb the superblock to get security mount options from
> - * @mount_options array for pointers to mount options
> - * @mount_flags array of ints specifying what each mount options is
> - * @num_opts number of options in the arrays
> + * @opts binary data structure containing all lsm mount data
> * @sb_set_mnt_opts:
> * Set the security relevant mount options used for a superblock
> * @sb the superblock to set security mount options for
> - * @mount_options array for pointers to mount options
> - * @mount_flags array of ints specifying what each mount options is
> - * @num_opts number of options in the arrays
> + * @opts binary data structure containing all lsm mount data
> * @sb_clone_mnt_opts:
> * Copy all security options from a given superblock to another
> * @oldsb old superblock which contain information to clone
> * @newsb new superblock which needs filled in
> + * @sb_parse_opts_str:
> + * Parse a string of security data filling in the opts structure
> + * @options string containing all mount options known by the LSM
> + * @opts binary data structure usable by the LSM
> *
> * Security hooks for inode operations.
> *
> @@ -1238,8 +1258,7 @@ struct security_operations {
>
> int (*sb_alloc_security) (struct super_block * sb);
> void (*sb_free_security) (struct super_block * sb);
> - int (*sb_copy_data)(struct file_system_type *type,
> - void *orig, void *copy);
> + int (*sb_copy_data)(char *orig, char *copy);
> int (*sb_kern_mount) (struct super_block *sb, void *data);
> int (*sb_statfs) (struct dentry *dentry);
> int (*sb_mount) (char *dev_name, struct nameidata * nd,
> @@ -1257,12 +1276,12 @@ struct security_operations {
> void (*sb_post_pivotroot) (struct nameidata * old_nd,
> struct nameidata * new_nd);
> int (*sb_get_mnt_opts) (const struct super_block *sb,
> - char ***mount_options, int **flags,
> - int *num_opts);
> - int (*sb_set_mnt_opts) (struct super_block *sb, char **mount_options,
> - int *flags, int num_opts);
> + struct security_mnt_opts *opts);
> + int (*sb_set_mnt_opts) (struct super_block *sb,
> + struct security_mnt_opts *opts);
> void (*sb_clone_mnt_opts) (const struct super_block *oldsb,
> struct super_block *newsb);
> + int (*sb_parse_opts_str) (char *options, struct security_mnt_opts *opts);
>
> int (*inode_alloc_security) (struct inode *inode);
> void (*inode_free_security) (struct inode *inode);
> @@ -1507,7 +1526,7 @@ int security_bprm_check(struct linux_binprm *bprm);
> int security_bprm_secureexec(struct linux_binprm *bprm);
> int security_sb_alloc(struct super_block *sb);
> void security_sb_free(struct super_block *sb);
> -int security_sb_copy_data(struct file_system_type *type, void *orig, void *copy);
> +int security_sb_copy_data(char *orig, char *copy);
> int security_sb_kern_mount(struct super_block *sb, void *data);
> int security_sb_statfs(struct dentry *dentry);
> int security_sb_mount(char *dev_name, struct nameidata *nd,
> @@ -1520,12 +1539,12 @@ void security_sb_post_remount(struct vfsmount *mnt, unsigned long flags, void *d
> void security_sb_post_addmount(struct vfsmount *mnt, struct nameidata *mountpoint_nd);
> int security_sb_pivotroot(struct nameidata *old_nd, struct nameidata *new_nd);
> void security_sb_post_pivotroot(struct nameidata *old_nd, struct nameidata *new_nd);
> -int security_sb_get_mnt_opts(const struct super_block *sb, char ***mount_options,
> - int **flags, int *num_opts);
> -int security_sb_set_mnt_opts(struct super_block *sb, char **mount_options,
> - int *flags, int num_opts);
> +int security_sb_get_mnt_opts(const struct super_block *sb,
> + struct security_mnt_opts *opts);
> +int security_sb_set_mnt_opts(struct super_block *sb, struct security_mnt_opts *opts);
> void security_sb_clone_mnt_opts(const struct super_block *oldsb,
> struct super_block *newsb);
> +int security_sb_parse_opts_str(char *options, struct security_mnt_opts *opts);
>
> int security_inode_alloc(struct inode *inode);
> void security_inode_free(struct inode *inode);
> @@ -1635,6 +1654,16 @@ int security_secctx_to_secid(char *secdata, u32 seclen, u32 *secid);
> void security_release_secctx(char *secdata, u32 seclen);
>
> #else /* CONFIG_SECURITY */
> +struct security_mnt_opts {
> +};
> +
> +static inline void security_init_mnt_opts(struct security_mnt_opts *opts)
> +{
> +}
> +
> +static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
> +{
> +}
>
> /*
> * This is the default capabilities functionality. Most of these functions
> @@ -1762,8 +1791,7 @@ static inline int security_sb_alloc (struct super_block *sb)
> static inline void security_sb_free (struct super_block *sb)
> { }
>
> -static inline int security_sb_copy_data (struct file_system_type *type,
> - void *orig, void *copy)
> +static inline int security_sb_copy_data (char *orig, char *copy)
> {
> return 0;
> }
> @@ -1819,6 +1847,27 @@ static inline int security_sb_pivotroot (struct nameidata *old_nd,
> static inline void security_sb_post_pivotroot (struct nameidata *old_nd,
> struct nameidata *new_nd)
> { }
> +static inline int security_sb_get_mnt_opts(const struct super_block *sb,
> + struct security_mnt_opts *opts)
> +{
> + security_init_mnt_opts(opts);
> + return 0;
> +}
> +
> +static inline int security_sb_set_mnt_opts(struct super_block *sb,
> + struct security_mnt_opts *opts)
> +{
> + return 0;
> +}
> +
> +static inline void security_sb_clone_mnt_opts(const struct super_block *oldsb,
> + struct super_block *newsb)
> +{ }
> +
> +static inline int security_sb_parse_opts_str(char *options, struct security_mnt_opts *opts)
> +{
> + return 0;
> +}
>
> static inline int security_inode_alloc (struct inode *inode)
> {
> diff --git a/security/dummy.c b/security/dummy.c
> index 649326b..78d8f92 100644
> --- a/security/dummy.c
> +++ b/security/dummy.c
> @@ -181,8 +181,7 @@ static void dummy_sb_free_security (struct super_block *sb)
> return;
> }
>
> -static int dummy_sb_copy_data (struct file_system_type *type,
> - void *orig, void *copy)
> +static int dummy_sb_copy_data (char *orig, char *copy)
> {
> return 0;
> }
> @@ -245,19 +244,17 @@ static void dummy_sb_post_pivotroot (struct nameidata *old_nd, struct nameidata
> return;
> }
>
> -static int dummy_sb_get_mnt_opts(const struct super_block *sb, char ***mount_options,
> - int **flags, int *num_opts)
> +static int dummy_sb_get_mnt_opts(const struct super_block *sb,
> + struct security_mnt_opts *opts)
> {
> - *mount_options = NULL;
> - *flags = NULL;
> - *num_opts = 0;
> + security_init_mnt_opts(opts);
> return 0;
> }
>
> -static int dummy_sb_set_mnt_opts(struct super_block *sb, char **mount_options,
> - int *flags, int num_opts)
> +static int dummy_sb_set_mnt_opts(struct super_block *sb,
> + struct security_mnt_opts *opts)
> {
> - if (unlikely(num_opts))
> + if (unlikely(opts->num_mnt_opts))
> return -EOPNOTSUPP;
> return 0;
> }
> @@ -268,6 +265,11 @@ static void dummy_sb_clone_mnt_opts(const struct super_block *oldsb,
> return;
> }
>
> +static int dummy_sb_parse_opts_str(char *options, struct security_mnt_opts *opts)
> +{
> + return 0;
> +}
> +
> static int dummy_inode_alloc_security (struct inode *inode)
> {
> return 0;
> @@ -1028,6 +1030,7 @@ void security_fixup_ops (struct security_operations *ops)
> set_to_dummy_if_null(ops, sb_get_mnt_opts);
> set_to_dummy_if_null(ops, sb_set_mnt_opts);
> set_to_dummy_if_null(ops, sb_clone_mnt_opts);
> + set_to_dummy_if_null(ops, sb_parse_opts_str);
> set_to_dummy_if_null(ops, inode_alloc_security);
> set_to_dummy_if_null(ops, inode_free_security);
> set_to_dummy_if_null(ops, inode_init_security);
> diff --git a/security/security.c b/security/security.c
> index d15e56c..b1387a6 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -244,10 +244,11 @@ void security_sb_free(struct super_block *sb)
> security_ops->sb_free_security(sb);
> }
>
> -int security_sb_copy_data(struct file_system_type *type, void *orig, void *copy)
> +int security_sb_copy_data(char *orig, char *copy)
> {
> - return security_ops->sb_copy_data(type, orig, copy);
> + return security_ops->sb_copy_data(orig, copy);
> }
> +EXPORT_SYMBOL(security_sb_copy_data);
>
> int security_sb_kern_mount(struct super_block *sb, void *data)
> {
> @@ -306,24 +307,30 @@ void security_sb_post_pivotroot(struct nameidata *old_nd, struct nameidata *new_
> }
>
> int security_sb_get_mnt_opts(const struct super_block *sb,
> - char ***mount_options,
> - int **flags, int *num_opts)
> + struct security_mnt_opts *opts)
> {
> - return security_ops->sb_get_mnt_opts(sb, mount_options, flags, num_opts);
> + return security_ops->sb_get_mnt_opts(sb, opts);
> }
>
> int security_sb_set_mnt_opts(struct super_block *sb,
> - char **mount_options,
> - int *flags, int num_opts)
> + struct security_mnt_opts *opts)
> {
> - return security_ops->sb_set_mnt_opts(sb, mount_options, flags, num_opts);
> + return security_ops->sb_set_mnt_opts(sb, opts);
> }
> +EXPORT_SYMBOL(security_sb_set_mnt_opts);
>
> void security_sb_clone_mnt_opts(const struct super_block *oldsb,
> struct super_block *newsb)
> {
> security_ops->sb_clone_mnt_opts(oldsb, newsb);
> }
> +EXPORT_SYMBOL(security_sb_clone_mnt_opts);
> +
> +int security_sb_parse_opts_str(char *options, struct security_mnt_opts *opts)
> +{
> + return security_ops->sb_parse_opts_str(options, opts);
> +}
> +EXPORT_SYMBOL(security_sb_parse_opts_str);
>
> int security_inode_alloc(struct inode *inode)
> {
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 75c2e99..dea6d21 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -443,8 +443,7 @@ out:
> * mount options, or whatever.
> */
> static int selinux_get_mnt_opts(const struct super_block *sb,
> - char ***mount_options, int **mnt_opts_flags,
> - int *num_opts)
> + struct security_mnt_opts *opts)
> {
> int rc = 0, i;
> struct superblock_security_struct *sbsec = sb->s_security;
> @@ -452,9 +451,7 @@ static int selinux_get_mnt_opts(const struct super_block *sb,
> u32 len;
> char tmp;
>
> - *num_opts = 0;
> - *mount_options = NULL;
> - *mnt_opts_flags = NULL;
> + security_init_mnt_opts(opts);
>
> if (!sbsec->initialized)
> return -EINVAL;
> @@ -470,18 +467,18 @@ static int selinux_get_mnt_opts(const struct super_block *sb,
> /* count the number of mount options for this sb */
> for (i = 0; i < 8; i++) {
> if (tmp & 0x01)
> - (*num_opts)++;
> + opts->num_mnt_opts++;
> tmp >>= 1;
> }
>
> - *mount_options = kcalloc(*num_opts, sizeof(char *), GFP_ATOMIC);
> - if (!*mount_options) {
> + opts->mnt_opts = kcalloc(opts->num_mnt_opts, sizeof(char *), GFP_ATOMIC);
> + if (!opts->mnt_opts) {
> rc = -ENOMEM;
> goto out_free;
> }
>
> - *mnt_opts_flags = kcalloc(*num_opts, sizeof(int), GFP_ATOMIC);
> - if (!*mnt_opts_flags) {
> + opts->mnt_opts_flags = kcalloc(opts->num_mnt_opts, sizeof(int), GFP_ATOMIC);
> + if (!opts->mnt_opts_flags) {
> rc = -ENOMEM;
> goto out_free;
> }
> @@ -491,22 +488,22 @@ static int selinux_get_mnt_opts(const struct super_block *sb,
> rc = security_sid_to_context(sbsec->sid, &context, &len);
> if (rc)
> goto out_free;
> - (*mount_options)[i] = context;
> - (*mnt_opts_flags)[i++] = FSCONTEXT_MNT;
> + opts->mnt_opts[i] = context;
> + opts->mnt_opts_flags[i++] = FSCONTEXT_MNT;
> }
> if (sbsec->flags & CONTEXT_MNT) {
> rc = security_sid_to_context(sbsec->mntpoint_sid, &context, &len);
> if (rc)
> goto out_free;
> - (*mount_options)[i] = context;
> - (*mnt_opts_flags)[i++] = CONTEXT_MNT;
> + opts->mnt_opts[i] = context;
> + opts->mnt_opts_flags[i++] = CONTEXT_MNT;
> }
> if (sbsec->flags & DEFCONTEXT_MNT) {
> rc = security_sid_to_context(sbsec->def_sid, &context, &len);
> if (rc)
> goto out_free;
> - (*mount_options)[i] = context;
> - (*mnt_opts_flags)[i++] = DEFCONTEXT_MNT;
> + opts->mnt_opts[i] = context;
> + opts->mnt_opts_flags[i++] = DEFCONTEXT_MNT;
> }
> if (sbsec->flags & ROOTCONTEXT_MNT) {
> struct inode *root = sbsec->sb->s_root->d_inode;
> @@ -515,24 +512,16 @@ static int selinux_get_mnt_opts(const struct super_block *sb,
> rc = security_sid_to_context(isec->sid, &context, &len);
> if (rc)
> goto out_free;
> - (*mount_options)[i] = context;
> - (*mnt_opts_flags)[i++] = ROOTCONTEXT_MNT;
> + opts->mnt_opts[i] = context;
> + opts->mnt_opts_flags[i++] = ROOTCONTEXT_MNT;
> }
>
> - BUG_ON(i != *num_opts);
> + BUG_ON(i != opts->num_mnt_opts);
>
> return 0;
>
> out_free:
> - /* don't leak context string if security_sid_to_context had an error */
> - if (*mount_options && i)
> - for (; i > 0; i--)
> - kfree((*mount_options)[i-1]);
> - kfree(*mount_options);
> - *mount_options = NULL;
> - kfree(*mnt_opts_flags);
> - *mnt_opts_flags = NULL;
> - *num_opts = 0;
> + security_free_mnt_opts(opts);
> return rc;
> }
>
> @@ -553,12 +542,13 @@ static int bad_option(struct superblock_security_struct *sbsec, char flag,
> return 1;
> return 0;
> }
> +
> /*
> * Allow filesystems with binary mount data to explicitly set mount point
> * labeling information.
> */
> -static int selinux_set_mnt_opts(struct super_block *sb, char **mount_options,
> - int *flags, int num_opts)
> +static int selinux_set_mnt_opts(struct super_block *sb,
> + struct security_mnt_opts *opts)
> {
> int rc = 0, i;
> struct task_security_struct *tsec = current->security;
> @@ -568,6 +558,9 @@ static int selinux_set_mnt_opts(struct super_block *sb, char **mount_options,
> struct inode_security_struct *root_isec = inode->i_security;
> u32 fscontext_sid = 0, context_sid = 0, rootcontext_sid = 0;
> u32 defcontext_sid = 0;
> + char **mount_options = opts->mnt_opts;
> + int *flags = opts->mnt_opts_flags;
> + int num_opts = opts->num_mnt_opts;
>
> mutex_lock(&sbsec->lock);
>
> @@ -589,6 +582,21 @@ static int selinux_set_mnt_opts(struct super_block *sb, char **mount_options,
> }
>
> /*
> + * Binary mount data FS will come through this function twice. Once
> + * from an explicit call and once from the generic calls from the vfs.
> + * Since the generic VFS calls will not contain any security mount data
> + * we need to skip the double mount verification.
> + *
> + * This does open a hole in which we will not notice if the first
> + * mount using this sb set explict options and a second mount using
> + * this sb does not set any security options. (The first options
> + * will be used for both mounts)
> + */
> + if (sbsec->initialized && (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA)
> + && (num_opts == 0))
> + goto out;
> +
I'm not sure I understand this. What purpose does checking num_opts
serve here?
> + /*
> * parse the mount options, check if they are valid sids.
> * also check if someone is trying to mount the same sb more
> * than once with different security options.
> @@ -792,43 +800,14 @@ static void selinux_sb_clone_mnt_opts(const struct super_block *oldsb,
> mutex_unlock(&newsbsec->lock);
> }
>
> -/*
> - * string mount options parsing and call set the sbsec
> - */
> -static int superblock_doinit(struct super_block *sb, void *data)
> +int selinux_parse_opts_str(char *options, struct security_mnt_opts *opts)
> {
> + char *p;
> char *context = NULL, *defcontext = NULL;
> char *fscontext = NULL, *rootcontext = NULL;
> - int rc = 0;
> - char *p, *options = data;
> - /* selinux only know about a fixed number of mount options */
> - char *mnt_opts[NUM_SEL_MNT_OPTS];
> - int mnt_opts_flags[NUM_SEL_MNT_OPTS], num_mnt_opts = 0;
> -
> - if (!data)
> - goto out;
> + int rc, num_mnt_opts = 0;
>
> - /* with the nfs patch this will become a goto out; */
> - if (sb->s_type->fs_flags & FS_BINARY_MOUNTDATA) {
> - const char *name = sb->s_type->name;
> - /* NFS we understand. */
> - if (!strcmp(name, "nfs")) {
> - struct nfs_mount_data *d = data;
> -
> - if (d->version != NFS_MOUNT_VERSION)
> - goto out;
> -
> - if (d->context[0]) {
> - context = kstrdup(d->context, GFP_KERNEL);
> - if (!context) {
> - rc = -ENOMEM;
> - goto out;
> - }
> - }
> - goto build_flags;
> - } else
> - goto out;
> - }
> + opts->num_mnt_opts = 0;
>
> /* Standard string-based options. */
> while ((p = strsep(&options, "|")) != NULL) {
> @@ -901,26 +880,37 @@ static int superblock_doinit(struct super_block *sb, void *data)
> }
> }
>
> -build_flags:
> + rc = -ENOMEM;
> + opts->mnt_opts = kcalloc(NUM_SEL_MNT_OPTS, sizeof(char *), GFP_ATOMIC);
> + if (!opts->mnt_opts)
> + goto out_err;
> +
> + opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int), GFP_ATOMIC);
> + if (!opts->mnt_opts_flags) {
> + kfree(opts->mnt_opts);
> + goto out_err;
> + }
> +
> if (fscontext) {
> - mnt_opts[num_mnt_opts] = fscontext;
> - mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
> + opts->mnt_opts[num_mnt_opts] = fscontext;
> + opts->mnt_opts_flags[num_mnt_opts++] = FSCONTEXT_MNT;
> }
> if (context) {
> - mnt_opts[num_mnt_opts] = context;
> - mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
> + opts->mnt_opts[num_mnt_opts] = context;
> + opts->mnt_opts_flags[num_mnt_opts++] = CONTEXT_MNT;
> }
> if (rootcontext) {
> - mnt_opts[num_mnt_opts] = rootcontext;
> - mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
> + opts->mnt_opts[num_mnt_opts] = rootcontext;
> + opts->mnt_opts_flags[num_mnt_opts++] = ROOTCONTEXT_MNT;
> }
> if (defcontext) {
> - mnt_opts[num_mnt_opts] = defcontext;
> - mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
> + opts->mnt_opts[num_mnt_opts] = defcontext;
> + opts->mnt_opts_flags[num_mnt_opts++] = DEFCONTEXT_MNT;
> }
>
> -out:
> - rc = selinux_set_mnt_opts(sb, mnt_opts, mnt_opts_flags, num_mnt_opts);
> + opts->num_mnt_opts = num_mnt_opts;
> + return 0;
> +
> out_err:
> kfree(context);
> kfree(defcontext);
> @@ -928,6 +918,33 @@ out_err:
> kfree(rootcontext);
> return rc;
> }
> +/*
> + * string mount options parsing and call set the sbsec
> + */
> +static int superblock_doinit(struct super_block *sb, void *data)
> +{
> + int rc = 0;
> + char *options = data;
> + struct security_mnt_opts opts;
> +
> + security_init_mnt_opts(&opts);
> +
> + if (!data)
> + goto out;
> +
> + BUG_ON(sb->s_type->fs_flags & FS_BINARY_MOUNTDATA);
> +
> + rc = selinux_parse_opts_str(options, &opts);
> + if (rc)
> + goto out_err;
> +
> +out:
> + rc = selinux_set_mnt_opts(sb, &opts);
> +
> +out_err:
> + security_free_mnt_opts(&opts);
> + return rc;
> +}
>
> static inline u16 inode_mode_to_security_class(umode_t mode)
> {
> @@ -2253,7 +2270,7 @@ static inline void take_selinux_option(char **to, char *from, int *first,
> }
> }
>
> -static int selinux_sb_copy_data(struct file_system_type *type, void *orig, void *copy)
> +static int selinux_sb_copy_data(char *orig, char *copy)
> {
> int fnosec, fsec, rc = 0;
> char *in_save, *in_curr, *in_end;
> @@ -2263,12 +2280,6 @@ static int selinux_sb_copy_data(struct file_system_type *type, void *orig, void
> in_curr = orig;
> sec_curr = copy;
>
> - /* Binary mount data: just copy */
> - if (type->fs_flags & FS_BINARY_MOUNTDATA) {
> - copy_page(sec_curr, in_curr);
> - goto out;
> - }
> -
> nosec = (char *)get_zeroed_page(GFP_KERNEL);
> if (!nosec) {
> rc = -ENOMEM;
> @@ -5251,6 +5262,8 @@ static struct security_operations selinux_ops = {
> .sb_get_mnt_opts = selinux_get_mnt_opts,
> .sb_set_mnt_opts = selinux_set_mnt_opts,
> .sb_clone_mnt_opts = selinux_sb_clone_mnt_opts,
> + .sb_parse_opts_str = selinux_parse_opts_str,
> +
>
> .inode_alloc_security = selinux_inode_alloc_security,
> .inode_free_security = selinux_inode_free_security,
> diff --git a/security/selinux/include/security.h b/security/selinux/include/security.h
> index 837ce42..f7d2f03 100644
> --- a/security/selinux/include/security.h
> +++ b/security/selinux/include/security.h
> @@ -35,6 +35,11 @@
> #define POLICYDB_VERSION_MAX POLICYDB_VERSION_POLCAP
> #endif
>
> +#define CONTEXT_MNT 0x01
> +#define FSCONTEXT_MNT 0x02
> +#define ROOTCONTEXT_MNT 0x04
> +#define DEFCONTEXT_MNT 0x08
> +
> struct netlbl_lsm_secattr;
>
> extern int selinux_enabled;
> diff --git a/security/smack/smack_lsm.c b/security/smack/smack_lsm.c
> index 770eb06..0241fd3 100644
> --- a/security/smack/smack_lsm.c
> +++ b/security/smack/smack_lsm.c
> @@ -189,17 +189,10 @@ static void smack_sb_free_security(struct super_block *sb)
> * Copy the Smack specific mount options out of the mount
> * options list.
> */
> -static int smack_sb_copy_data(struct file_system_type *type, void *orig,
> - void *smackopts)
> +static int smack_sb_copy_data(char *orig, char *smackopts)
> {
> char *cp, *commap, *otheropts, *dp;
>
> - /* Binary mount data: just copy */
> - if (type->fs_flags & FS_BINARY_MOUNTDATA) {
> - copy_page(smackopts, orig);
> - return 0;
> - }
> -
> otheropts = (char *)get_zeroed_page(GFP_KERNEL);
> if (otheropts == NULL)
> return -ENOMEM;
>
>
--
Jeff Layton <jlayton@xxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
