Re: [PATCH 1/9] LSM: Introduce inode_getsecid and ipc_getsecid hooks

Introduce inode_getsecid(inode, secid) and ipc_getsecid(ipcp, secid) LSM hooks. These hooks will be used instead of similar exported SELinux interfaces. Let {inode,ipc,task}_getsecid hooks set the secid to 0 by default if CONFIG_SECURITY is not defined or if the hook is set to NULL (dummy). This is done to notify the caller that no valid secid exists. Signed-off-by: Casey Schaufler <casey(a)schaufler-ca.com&gt; Signed-off-by: Ahmed S. Darwish <darwish.07(a)gmail.com&gt;

--- include/linux/security.h | 30 +++++++++++++++++++++++++++++- security/dummy.c | 16 +++++++++++++++- security/security.c | 10 ++++++++++ 3 files changed, 54 insertions(+), 2 deletions(-) diff --git a/include/linux/security.h b/include/linux/security.h index a33fd03..205a053 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -449,6 +449,11 @@ struct request_sock; * @dentry is the dentry being changed. * Return 0 on success. If error is returned, then the operation * causing setuid bit removal is failed. + * @inode_getsecid: + * Get the secid associated with the node. + * @inode contains a pointer to the inode. + * @secid contains a pointer to the location where result will be saved. + * In case of failure, @secid will be set to zero. * * Security hooks for file operations * @@ -617,6 +622,8 @@ struct request_sock; * @task_getsecid: * Retrieve the security identifier of the process @p. * @p contains the task_struct for the process and place is into @secid. + * In case of failure, @secid will be set to zero. + * * @task_setgroups: * Check permission before setting the supplementary group set of the * current process. @@ -989,6 +996,11 @@ struct request_sock; * @ipcp contains the kernel IPC permission structure * @flag contains the desired (requested) permission set * Return 0 if permission is granted. + * @ipc_getsecid: + * Get the secid associated with the ipc object. + * @ipcp contains the kernel IPC permission structure. + * @secid contains a pointer to the location where result will be saved. + * In case of failure, @secid will be set to zero. * * Security hooks for individual messages held in System V IPC message queues * @msg_msg_alloc_security: @@ -1310,6 +1322,7 @@ struct security_operations { int (*inode_getsecurity)(const struct inode *inode, const char *name, void **buffer, bool alloc); int (*inode_setsecurity)(struct inode *inode, const char *name, const void *value, size_t size, int flags); int (*inode_listsecurity)(struct inode *inode, char *buffer, size_t buffer_size); + void (*inode_getsecid)(const struct inode *inode, u32 *secid); int (*file_permission) (struct file * file, int mask); int (*file_alloc_security) (struct file * file); @@ -1362,6 +1375,7 @@ struct security_operations { void (*task_to_inode)(struct task_struct *p, struct inode *inode); int (*ipc_permission) (struct kern_ipc_perm * ipcp, short flag); + void (*ipc_getsecid) (struct kern_ipc_perm *ipcp, u32 *secid); int (*msg_msg_alloc_security) (struct msg_msg * msg); void (*msg_msg_free_security) (struct msg_msg * msg); @@ -1571,6 +1585,7 @@ int security_inode_killpriv(struct dentry *dentry); int security_inode_getsecurity(const struct inode *inode, const char *name, void **buffer, bool alloc); int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags); int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size); +void security_inode_getsecid(const struct inode *inode, u32 *secid); int security_file_permission(struct file *file, int mask); int security_file_alloc(struct file *file); void security_file_free(struct file *file); @@ -1615,6 +1630,7 @@ int security_task_prctl(int option, unsigned long arg2, unsigned long arg3, void security_task_reparent_to_init(struct task_struct *p); void security_task_to_inode(struct task_struct *p, struct inode *inode); int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag); +void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid); int security_msg_msg_alloc(struct msg_msg *msg); void security_msg_msg_free(struct msg_msg *msg); int security_msg_queue_alloc(struct msg_queue *msq); @@ -1985,6 +2001,11 @@ static inline int security_inode_listsecurity(struct inode *inode, char *buffer, return 0; } +static inline void security_inode_getsecid(const struct inode *inode, u32 *secid) +{ + *secid = 0; +} + static inline int security_file_permission (struct file *file, int mask) { return 0; @@ -2100,7 +2121,9 @@ static inline int security_task_getsid (struct task_struct *p) } static inline void security_task_getsecid (struct task_struct *p, u32 *secid) -{ } +{ + *secid = 0; +} static inline int security_task_setgroups (struct group_info *group_info) { @@ -2179,6 +2202,11 @@ static inline int security_ipc_permission (struct kern_ipc_perm *ipcp, return 0; } +static inline void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid) +{ + *secid = 0; +} + static inline int security_msg_msg_alloc (struct msg_msg * msg) { return 0; diff --git a/security/dummy.c b/security/dummy.c index 6a0056b..f5e5f95 100644 --- a/security/dummy.c +++ b/security/dummy.c @@ -422,6 +422,11 @@ static int dummy_inode_listsecurity(struct inode *inode, char *buffer, size_t bu return 0; } +static void dummy_inode_getsecid(const struct inode *inode, u32 *secid) +{ + *secid = 0; +} + static int dummy_file_permission (struct file *file, int mask) { return 0; @@ -540,7 +545,9 @@ static int dummy_task_getsid (struct task_struct *p) } static void dummy_task_getsecid (struct task_struct *p, u32 *secid) -{ } +{ + *secid = 0; +} static int dummy_task_setgroups (struct group_info *group_info) { @@ -614,6 +621,11 @@ static int dummy_ipc_permission (struct kern_ipc_perm *ipcp, short flag) return 0; } +static void dummy_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid) +{ + *secid = 0; +} + static int dummy_msg_msg_alloc_security (struct msg_msg *msg) { return 0; @@ -1062,6 +1074,7 @@ void security_fixup_ops (struct security_operations *ops) set_to_dummy_if_null(ops, inode_getsecurity); set_to_dummy_if_null(ops, inode_setsecurity); set_to_dummy_if_null(ops, inode_listsecurity); + set_to_dummy_if_null(ops, inode_getsecid); set_to_dummy_if_null(ops, file_permission); set_to_dummy_if_null(ops, file_alloc_security); set_to_dummy_if_null(ops, file_free_security); @@ -1098,6 +1111,7 @@ void security_fixup_ops (struct security_operations *ops) set_to_dummy_if_null(ops, task_reparent_to_init); set_to_dummy_if_null(ops, task_to_inode); set_to_dummy_if_null(ops, ipc_permission); + set_to_dummy_if_null(ops, ipc_getsecid); set_to_dummy_if_null(ops, msg_msg_alloc_security); set_to_dummy_if_null(ops, msg_msg_free_security); set_to_dummy_if_null(ops, msg_queue_alloc_security); diff --git a/security/security.c b/security/security.c index 3e75b90..1748329 100644 --- a/security/security.c +++ b/security/security.c @@ -516,6 +516,11 @@ int security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer return security_ops->inode_listsecurity(inode, buffer, buffer_size); } +void security_inode_getsecid(const struct inode *inode, u32 *secid) +{ + security_ops->inode_getsecid(inode, secid); +} + int security_file_permission(struct file *file, int mask) { return security_ops->file_permission(file, mask); @@ -705,6 +710,11 @@ int security_ipc_permission(struct kern_ipc_perm *ipcp, short flag) return security_ops->ipc_permission(ipcp, flag); } +void security_ipc_getsecid(struct kern_ipc_perm *ipcp, u32 *secid) +{ + security_ops->ipc_getsecid(ipcp, secid); +} + int security_msg_msg_alloc(struct msg_msg *msg) { return security_ops->msg_msg_alloc_security(msg);