| Message ID | 20190109091028.24485-2-omosnace@redhat.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Allow initializing the kernfs node's secctx based on its parent | expand |
On 1/9/19 4:10 AM, Ondrej Mosnacek wrote: > This patch introduces a new security hook that is intended for > initializing the security data for newly created pseudo filesystem > objects (such as kernfs nodes) that provide a way of storing a > non-default security context, but need to operate independently from > mounts. > > The main motivation is to allow kernfs nodes to inherit the context of > the parent under SELinux, similar to the behavior of > security_inode_init_security(). Other LSMs may implement their own logic > for handling the creation of new nodes. > > Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> > --- > include/linux/lsm_hooks.h | 5 +++++ > include/linux/security.h | 12 ++++++++++++ > security/security.c | 8 ++++++++ > 3 files changed, 25 insertions(+) > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > index aaeb7fa24dc4..f2b4c0bf4a7b 100644 > --- a/include/linux/lsm_hooks.h > +++ b/include/linux/lsm_hooks.h > @@ -1556,6 +1556,10 @@ union security_list_options { > int (*inode_copy_up)(struct dentry *src, struct cred **new); > int (*inode_copy_up_xattr)(const char *name); > > + int (*object_init_security)(void *parent_ctx, u32 parent_ctxlen, > + const struct qstr *qstr, u16 mode, > + void **ctx, u32 *ctxlen); You'll want to add a kerneldoc comment for the new hook; see the existing ones for the other hooks at the top of lsm_hooks.h. > + > int (*file_permission)(struct file *file, int mask); > int (*file_alloc_security)(struct file *file); > void (*file_free_security)(struct file *file); > @@ -1855,6 +1859,7 @@ struct security_hook_heads { > struct hlist_head inode_getsecid; > struct hlist_head inode_copy_up; > struct hlist_head inode_copy_up_xattr; > + struct hlist_head object_init_security; > struct hlist_head file_permission; > struct hlist_head file_alloc_security; > struct hlist_head file_free_security; > diff --git a/include/linux/security.h b/include/linux/security.h > index d170a5b031f3..e20d1f378ea4 100644 > --- a/include/linux/security.h > +++ b/include/linux/security.h > @@ -315,6 +315,9 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer > void security_inode_getsecid(struct inode *inode, u32 *secid); > int security_inode_copy_up(struct dentry *src, struct cred **new); > int security_inode_copy_up_xattr(const char *name); > +int security_object_init_security(void *parent_ctx, u32 parent_ctxlen, > + const struct qstr *qstr, u16 mode, > + void **ctx, u32 *ctxlen); > int security_file_permission(struct file *file, int mask); > int security_file_alloc(struct file *file); > void security_file_free(struct file *file); > @@ -815,6 +818,15 @@ static inline int security_inode_copy_up_xattr(const char *name) > return -EOPNOTSUPP; > } > > +static inline int security_object_init_security(void *parent_ctx, > + u32 parent_ctxlen, > + const struct qstr *qstr, > + u16 mode, void **ctx, > + u32 *ctxlen) > +{ > + return 0; > +} > + > static inline int security_file_permission(struct file *file, int mask) > { > return 0; > diff --git a/security/security.c b/security/security.c > index 04d173eb93f6..56e77368b87f 100644 > --- a/security/security.c > +++ b/security/security.c > @@ -879,6 +879,14 @@ int security_inode_copy_up_xattr(const char *name) > } > EXPORT_SYMBOL(security_inode_copy_up_xattr); > > +int security_object_init_security(void *parent_ctx, u32 parent_ctxlen, > + const struct qstr *qstr, u16 mode, > + void **ctx, u32 *ctxlen) > +{ > + return call_int_hook(object_init_security, 0, parent_ctx, parent_ctxlen, > + qstr, mode, ctx, ctxlen); > +} > + > int security_file_permission(struct file *file, int mask) > { > int ret; >
On Wed, Jan 9, 2019 at 3:33 PM Stephen Smalley <sds@tycho.nsa.gov> wrote: > On 1/9/19 4:10 AM, Ondrej Mosnacek wrote: > > This patch introduces a new security hook that is intended for > > initializing the security data for newly created pseudo filesystem > > objects (such as kernfs nodes) that provide a way of storing a > > non-default security context, but need to operate independently from > > mounts. > > > > The main motivation is to allow kernfs nodes to inherit the context of > > the parent under SELinux, similar to the behavior of > > security_inode_init_security(). Other LSMs may implement their own logic > > for handling the creation of new nodes. > > > > Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> > > --- > > include/linux/lsm_hooks.h | 5 +++++ > > include/linux/security.h | 12 ++++++++++++ > > security/security.c | 8 ++++++++ > > 3 files changed, 25 insertions(+) > > > > diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h > > index aaeb7fa24dc4..f2b4c0bf4a7b 100644 > > --- a/include/linux/lsm_hooks.h > > +++ b/include/linux/lsm_hooks.h > > @@ -1556,6 +1556,10 @@ union security_list_options { > > int (*inode_copy_up)(struct dentry *src, struct cred **new); > > int (*inode_copy_up_xattr)(const char *name); > > > > + int (*object_init_security)(void *parent_ctx, u32 parent_ctxlen, > > + const struct qstr *qstr, u16 mode, > > + void **ctx, u32 *ctxlen); > > You'll want to add a kerneldoc comment for the new hook; see the > existing ones for the other hooks at the top of lsm_hooks.h. Good point, will add that in v2, thanks. > > > + > > int (*file_permission)(struct file *file, int mask); > > int (*file_alloc_security)(struct file *file); > > void (*file_free_security)(struct file *file); > > @@ -1855,6 +1859,7 @@ struct security_hook_heads { > > struct hlist_head inode_getsecid; > > struct hlist_head inode_copy_up; > > struct hlist_head inode_copy_up_xattr; > > + struct hlist_head object_init_security; > > struct hlist_head file_permission; > > struct hlist_head file_alloc_security; > > struct hlist_head file_free_security; > > diff --git a/include/linux/security.h b/include/linux/security.h > > index d170a5b031f3..e20d1f378ea4 100644 > > --- a/include/linux/security.h > > +++ b/include/linux/security.h > > @@ -315,6 +315,9 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer > > void security_inode_getsecid(struct inode *inode, u32 *secid); > > int security_inode_copy_up(struct dentry *src, struct cred **new); > > int security_inode_copy_up_xattr(const char *name); > > +int security_object_init_security(void *parent_ctx, u32 parent_ctxlen, > > + const struct qstr *qstr, u16 mode, > > + void **ctx, u32 *ctxlen); > > int security_file_permission(struct file *file, int mask); > > int security_file_alloc(struct file *file); > > void security_file_free(struct file *file); > > @@ -815,6 +818,15 @@ static inline int security_inode_copy_up_xattr(const char *name) > > return -EOPNOTSUPP; > > } > > > > +static inline int security_object_init_security(void *parent_ctx, > > + u32 parent_ctxlen, > > + const struct qstr *qstr, > > + u16 mode, void **ctx, > > + u32 *ctxlen) > > +{ > > + return 0; I just realized I will need to assign *ctx to NULL and *ctxlen to 0 here, since I chose to return 0 by default... > > +} > > + > > static inline int security_file_permission(struct file *file, int mask) > > { > > return 0; > > diff --git a/security/security.c b/security/security.c > > index 04d173eb93f6..56e77368b87f 100644 > > --- a/security/security.c > > +++ b/security/security.c > > @@ -879,6 +879,14 @@ int security_inode_copy_up_xattr(const char *name) > > } > > EXPORT_SYMBOL(security_inode_copy_up_xattr); > > > > +int security_object_init_security(void *parent_ctx, u32 parent_ctxlen, > > + const struct qstr *qstr, u16 mode, > > + void **ctx, u32 *ctxlen) > > +{ > > + return call_int_hook(object_init_security, 0, parent_ctx, parent_ctxlen, > > + qstr, mode, ctx, ctxlen); Same here, in case there is no object_init_security hook provided by the LSM. > > +} > > + > > int security_file_permission(struct file *file, int mask) > > { > > int ret; > > >
diff --git a/include/linux/lsm_hooks.h b/include/linux/lsm_hooks.h index aaeb7fa24dc4..f2b4c0bf4a7b 100644 --- a/include/linux/lsm_hooks.h +++ b/include/linux/lsm_hooks.h @@ -1556,6 +1556,10 @@ union security_list_options { int (*inode_copy_up)(struct dentry *src, struct cred **new); int (*inode_copy_up_xattr)(const char *name); + int (*object_init_security)(void *parent_ctx, u32 parent_ctxlen, + const struct qstr *qstr, u16 mode, + void **ctx, u32 *ctxlen); + int (*file_permission)(struct file *file, int mask); int (*file_alloc_security)(struct file *file); void (*file_free_security)(struct file *file); @@ -1855,6 +1859,7 @@ struct security_hook_heads { struct hlist_head inode_getsecid; struct hlist_head inode_copy_up; struct hlist_head inode_copy_up_xattr; + struct hlist_head object_init_security; struct hlist_head file_permission; struct hlist_head file_alloc_security; struct hlist_head file_free_security; diff --git a/include/linux/security.h b/include/linux/security.h index d170a5b031f3..e20d1f378ea4 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -315,6 +315,9 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer void security_inode_getsecid(struct inode *inode, u32 *secid); int security_inode_copy_up(struct dentry *src, struct cred **new); int security_inode_copy_up_xattr(const char *name); +int security_object_init_security(void *parent_ctx, u32 parent_ctxlen, + const struct qstr *qstr, u16 mode, + void **ctx, u32 *ctxlen); int security_file_permission(struct file *file, int mask); int security_file_alloc(struct file *file); void security_file_free(struct file *file); @@ -815,6 +818,15 @@ static inline int security_inode_copy_up_xattr(const char *name) return -EOPNOTSUPP; } +static inline int security_object_init_security(void *parent_ctx, + u32 parent_ctxlen, + const struct qstr *qstr, + u16 mode, void **ctx, + u32 *ctxlen) +{ + return 0; +} + static inline int security_file_permission(struct file *file, int mask) { return 0; diff --git a/security/security.c b/security/security.c index 04d173eb93f6..56e77368b87f 100644 --- a/security/security.c +++ b/security/security.c @@ -879,6 +879,14 @@ int security_inode_copy_up_xattr(const char *name) } EXPORT_SYMBOL(security_inode_copy_up_xattr); +int security_object_init_security(void *parent_ctx, u32 parent_ctxlen, + const struct qstr *qstr, u16 mode, + void **ctx, u32 *ctxlen) +{ + return call_int_hook(object_init_security, 0, parent_ctx, parent_ctxlen, + qstr, mode, ctx, ctxlen); +} + int security_file_permission(struct file *file, int mask) { int ret;
This patch introduces a new security hook that is intended for initializing the security data for newly created pseudo filesystem objects (such as kernfs nodes) that provide a way of storing a non-default security context, but need to operate independently from mounts. The main motivation is to allow kernfs nodes to inherit the context of the parent under SELinux, similar to the behavior of security_inode_init_security(). Other LSMs may implement their own logic for handling the creation of new nodes. Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com> --- include/linux/lsm_hooks.h | 5 +++++ include/linux/security.h | 12 ++++++++++++ security/security.c | 8 ++++++++ 3 files changed, 25 insertions(+)