From c9180a57a9ab2d5525faf8815a332364ee9e89b7 Mon Sep 17 00:00:00 2001 From: Eric Paris Date: Fri, 30 Nov 2007 13:00:35 -0500 Subject: Security: add get, set, and cloning of superblock security information Adds security_get_sb_mnt_opts, security_set_sb_mnt_opts, and security_clont_sb_mnt_opts to the LSM and to SELinux. This will allow filesystems to directly own and control all of their mount options if they so choose. This interface deals only with option identifiers and strings so it should generic enough for any LSM which may come in the future. Filesystems which pass text mount data around in the kernel (almost all of them) need not currently make use of this interface when dealing with SELinux since it will still parse those strings as it always has. I assume future LSM's would do the same. NFS is the primary FS which does not use text mount data and thus must make use of this interface. An LSM would need to implement these functions only if they had mount time options, such as selinux has context= or fscontext=. If the LSM has no mount time options they could simply not implement and let the dummy ops take care of things. An LSM other than SELinux would need to define new option numbers in security.h and any FS which decides to own there own security options would need to be patched to use this new interface for every possible LSM. This is because it was stated to me very clearly that LSM's should not attempt to understand FS mount data and the burdon to understand security should be in the FS which owns the options. Signed-off-by: Eric Paris Acked-by: Stephen D. Smalley Signed-off-by: James Morris --- include/linux/security.h | 36 ++++++++++++++++++++++++++++++++++++ 1 file changed, 36 insertions(+) (limited to 'include') diff --git a/include/linux/security.h b/include/linux/security.h index ac050830a87..cbd970a735f 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -34,6 +34,12 @@ #include #include +/* 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 + /* * Bounding set */ @@ -261,6 +267,22 @@ struct request_sock; * Update module state after a successful pivot. * @old_nd contains the nameidata structure for the old root. * @new_nd contains the nameidata structure for the new root. + * @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 + * @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 + * @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 * * Security hooks for inode operations. * @@ -1242,6 +1264,13 @@ struct security_operations { struct nameidata * new_nd); 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); + void (*sb_clone_mnt_opts) (const struct super_block *oldsb, + struct super_block *newsb); int (*inode_alloc_security) (struct inode *inode); void (*inode_free_security) (struct inode *inode); @@ -1499,6 +1528,13 @@ void security_sb_post_mountroot(void); 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); +void security_sb_clone_mnt_opts(const struct super_block *oldsb, + struct super_block *newsb); + int security_inode_alloc(struct inode *inode); void security_inode_free(struct inode *inode); int security_inode_init_security(struct inode *inode, struct inode *dir, -- cgit v1.2.3