On Mon, Nov 12, 2012 at 01:15:35AM -0500, David Quigley wrote:
> From: David Quigley <dpquigl@xxxxxxxxxxxxxxx>
>
> There is a time where we need to calculate a context without the
> inode having been created yet. To do this we take the negative dentry and
> calculate a context based on the process and the parent directory contexts.
>
> Signed-off-by: Matthew N. Dodd <Matthew.Dodd@xxxxxxxxxx>
> Signed-off-by: Miguel Rodel Felipe <Rodel_FM@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Phua Eu Gene <PHUA_Eu_Gene@xxxxxxxxxxxxxxxxx>
> Signed-off-by: Khin Mi Mi Aung <Mi_Mi_AUNG@xxxxxxxxxxxxxxxxx>
> Signed-off-by: David Quigley <dpquigl@xxxxxxxxxxxxxxx>
> ---
> include/linux/security.h | 27 +++++++++++++++++++++++++++
> security/capability.c | 8 ++++++++
> security/security.c | 10 ++++++++++
> security/selinux/hooks.c | 35 +++++++++++++++++++++++++++++++++++
> 4 files changed, 80 insertions(+)
>
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 05e88bd..c9f5eec 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -26,6 +26,7 @@
> #include <linux/capability.h>
> #include <linux/slab.h>
> #include <linux/err.h>
> +#include <linux/string.h>
>
> struct linux_binprm;
> struct cred;
> @@ -306,6 +307,15 @@ static inline void security_free_mnt_opts(struct security_mnt_opts *opts)
> * 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
> + * @dentry_init_security:
> + * Compute a context for a dentry as the inode is not yet available
> + * since NFSv4 has no label backed by an EA anyway.
I don't understand this comment. Why exactly is NFSv4 the first user
that needs this?
--b.
> + * @dentry dentry to use in calculating the context.
> + * @mode mode used to determine resource type.
> + * @name name of the last path component used to create file
> + * @ctx pointer to place the pointer to the resulting context in.
> + * @ctxlen point to place the length of the resulting context.
> + *
> *
> * Security hooks for inode operations.
> *
> @@ -1421,6 +1431,10 @@ struct security_operations {
> 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 (*dentry_init_security) (struct dentry *dentry, int mode,
> + struct qstr *name, void **ctx,
> + u32 *ctxlen);
> +
>
> #ifdef CONFIG_SECURITY_PATH
> int (*path_unlink) (struct path *dir, struct dentry *dentry);
> @@ -1702,6 +1716,9 @@ int security_sb_set_mnt_opts(struct super_block *sb, struct security_mnt_opts *o
> 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_dentry_init_security(struct dentry *dentry, int mode,
> + struct qstr *name, void **ctx,
> + u32 *ctxlen);
>
> int security_inode_alloc(struct inode *inode);
> void security_inode_free(struct inode *inode);
> @@ -2005,6 +2022,16 @@ static inline int security_inode_alloc(struct inode *inode)
> static inline void security_inode_free(struct inode *inode)
> { }
>
> +static inline int security_dentry_init_security(struct dentry *dentry,
> + int mode,
> + struct qstr *name,
> + void **ctx,
> + u32 *ctxlen)
> +{
> + return -EOPNOTSUPP;
> +}
> +
> +
> static inline int security_inode_init_security(struct inode *inode,
> struct inode *dir,
> const struct qstr *qstr,
> diff --git a/security/capability.c b/security/capability.c
> index b14a30c..f1eb284 100644
> --- a/security/capability.c
> +++ b/security/capability.c
> @@ -108,6 +108,13 @@ static int cap_sb_parse_opts_str(char *options, struct security_mnt_opts *opts)
> return 0;
> }
>
> +static int cap_dentry_init_security(struct dentry *dentry, int mode,
> + struct qstr *name, void **ctx,
> + u32 *ctxlen)
> +{
> + return 0;
> +}
> +
> static int cap_inode_alloc_security(struct inode *inode)
> {
> return 0;
> @@ -905,6 +912,7 @@ void __init security_fixup_ops(struct security_operations *ops)
> set_to_cap_if_null(ops, sb_set_mnt_opts);
> set_to_cap_if_null(ops, sb_clone_mnt_opts);
> set_to_cap_if_null(ops, sb_parse_opts_str);
> + set_to_cap_if_null(ops, dentry_init_security);
> set_to_cap_if_null(ops, inode_alloc_security);
> set_to_cap_if_null(ops, inode_free_security);
> set_to_cap_if_null(ops, inode_init_security);
> diff --git a/security/security.c b/security/security.c
> index 8dcd4ae..b4b2017 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -12,6 +12,7 @@
> */
>
> #include <linux/capability.h>
> +#include <linux/dcache.h>
> #include <linux/module.h>
> #include <linux/init.h>
> #include <linux/kernel.h>
> @@ -324,6 +325,15 @@ void security_inode_free(struct inode *inode)
> security_ops->inode_free_security(inode);
> }
>
> +int security_dentry_init_security(struct dentry *dentry, int mode,
> + struct qstr *name, void **ctx,
> + u32 *ctxlen)
> +{
> + return security_ops->dentry_init_security(dentry, mode, name,
> + ctx, ctxlen);
> +}
> +EXPORT_SYMBOL(security_dentry_init_security);
> +
> int security_inode_init_security(struct inode *inode, struct inode *dir,
> const struct qstr *qstr,
> const initxattrs initxattrs, void *fs_data)
> diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
> index 61a5336..22d9adf 100644
> --- a/security/selinux/hooks.c
> +++ b/security/selinux/hooks.c
> @@ -2483,6 +2483,40 @@ static void selinux_inode_free_security(struct inode *inode)
> inode_free_security(inode);
> }
>
> +static int selinux_dentry_init_security(struct dentry *dentry, int mode,
> + struct qstr *name, void **ctx,
> + u32 *ctxlen)
> +{
> + struct cred *cred = current_cred();
> + struct task_security_struct *tsec;
> + struct inode_security_struct *dsec;
> + struct superblock_security_struct *sbsec;
> + struct inode *dir = dentry->d_parent->d_inode;
> + u32 newsid;
> + int rc;
> +
> + tsec = cred->security;
> + dsec = dir->i_security;
> + sbsec = dir->i_sb->s_security;
> +
> + if (tsec->create_sid && sbsec->behavior != SECURITY_FS_USE_MNTPOINT) {
> + newsid = tsec->create_sid;
> + } else {
> + rc = security_transition_sid(tsec->sid, dsec->sid,
> + inode_mode_to_security_class(mode),
> + name,
> + &newsid);
> + if (rc) {
> + printk(KERN_WARNING
> + "%s: security_transition_sid failed, rc=%d\n",
> + __func__, -rc);
> + return rc;
> + }
> + }
> +
> + return security_sid_to_context(newsid, (char **)ctx, ctxlen);
> +}
> +
> static int selinux_inode_init_security(struct inode *inode, struct inode *dir,
> const struct qstr *qstr, char **name,
> void **value, size_t *len)
> @@ -5509,6 +5543,7 @@ static struct security_operations selinux_ops = {
> .sb_clone_mnt_opts = selinux_sb_clone_mnt_opts,
> .sb_parse_opts_str = selinux_parse_opts_str,
>
> + .dentry_init_security = selinux_dentry_init_security,
>
> .inode_alloc_security = selinux_inode_alloc_security,
> .inode_free_security = selinux_inode_free_security,
> --
> 1.7.11.7
>
--
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