Linux Security Module Development¶
Based on https://lore.kernel.org/r/20071026073721.618b4778@laptopd505.fenrus.org,
a new LSM is accepted into the kernel when its intent (a description of
what it tries to protect against and in what cases one would expect to
use it) has been appropriately documented in Documentation/admin-guide/LSM/.
This allows an LSM's code to be easily compared to its goals, and so
that end users and distros can make a more informed decision about which
LSMs suit their requirements.
For extensive documentation on the available LSM hook interfaces, please
see security/security.c and associated structures:
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void
security_free_mnt_opts(void **mnt_opts)¶ Free memory associated with mount options
Parameters
void **mnt_opts- LSM processed mount options
Description
Free memory associated with mnt_ops.
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int
security_sb_eat_lsm_opts(char *options, void **mnt_opts)¶ Consume LSM mount options
Parameters
char *options- mount options
void **mnt_opts- LSM processed mount options
Description
Eat (scan options) and save them in mnt_opts.
Return
Returns 0 on success, negative values on failure.
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int
security_sb_mnt_opts_compat(struct super_block *sb, void *mnt_opts)¶ Check if new mount options are allowed
Parameters
struct super_block *sb- filesystem superblock
void *mnt_opts- new mount options
Description
Determine if the new mount options in mnt_opts are allowed given the existing mounted filesystem at sb. sb superblock being compared.
Return
Returns 0 if options are compatible.
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int
security_sb_remount(struct super_block *sb, void *mnt_opts)¶ Verify no incompatible mount changes during remount
Parameters
struct super_block *sb- filesystem superblock
void *mnt_opts- (re)mount options
Description
Extracts security system specific mount options and verifies no changes are being made to those options.
Return
Returns 0 if permission is granted.
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int
security_sb_set_mnt_opts(struct super_block *sb, void *mnt_opts, unsigned long kern_flags, unsigned long *set_kern_flags)¶ Set the mount options for a filesystem
Parameters
struct super_block *sb- filesystem superblock
void *mnt_opts- binary mount options
unsigned long kern_flags- kernel flags (in)
unsigned long *set_kern_flags- kernel flags (out)
Description
Set the security relevant mount options used for a superblock.
Return
Returns 0 on success, error on failure.
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int
security_sb_clone_mnt_opts(const struct super_block *oldsb, struct super_block *newsb, unsigned long kern_flags, unsigned long *set_kern_flags)¶ Duplicate superblock mount options
Parameters
const struct super_block *oldsb- source superblock
struct super_block *newsb- destination superblock
unsigned long kern_flags- kernel flags (in)
unsigned long *set_kern_flags- kernel flags (out)
Description
Copy all security options from a given superblock to another.
Return
Returns 0 on success, error on failure.
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int
security_dentry_init_security(struct dentry *dentry, int mode, const struct qstr *name, const char **xattr_name, void **ctx, u32 *ctxlen)¶ Perform dentry initialization
Parameters
struct dentry *dentry- the dentry to initialize
int mode- mode used to determine resource type
const struct qstr *name- name of the last path component
const char **xattr_name- name of the security/LSM xattr
void **ctx- pointer to the resulting LSM context
u32 *ctxlen- length of ctx
Description
Compute a context for a dentry as the inode is not yet available since NFSv4 has no label backed by an EA anyway. It is important to note that xattr_name does not need to be free'd by the caller, it is a static string.
Return
Returns 0 on success, negative values on failure.
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int
security_dentry_create_files_as(struct dentry *dentry, int mode, struct qstr *name, const struct cred *old, struct cred *new)¶ Perform dentry initialization
Parameters
struct dentry *dentry- the dentry to initialize
int mode- mode used to determine resource type
struct qstr *name- name of the last path component
const struct cred *old- creds to use for LSM context calculations
struct cred *new- creds to modify
Description
Compute a context for a dentry as the inode is not yet available and set that context in passed in creds so that new files are created using that context. Context is calculated using the passed in creds and not the creds of the caller.
Return
Returns 0 on success, error on failure.
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int
security_inode_init_security(struct inode *inode, struct inode *dir, const struct qstr *qstr, const initxattrs initxattrs, void *fs_data)¶ Initialize an inode's LSM context
Parameters
struct inode *inode- the inode
struct inode *dir- parent directory
const struct qstr *qstr- last component of the pathname
const initxattrs initxattrs- callback function to write xattrs
void *fs_data- filesystem specific data
Description
Obtain the security attribute name suffix and value to set on a newly created inode and set up the incore security field for the new inode. This hook is called by the fs code as part of the inode creation transaction and provides for atomic labeling of the inode, unlike the post_create/mkdir/... hooks called by the VFS.
The hook function is expected to populate the xattrs array, by calling lsm_get_xattr_slot() to retrieve the slots reserved by the security module with the lbs_xattr_count field of the lsm_blob_sizes structure. For each slot, the hook function should set ->name to the attribute name suffix (e.g. selinux), to allocate ->value (will be freed by the caller) and set it to the attribute value, to set ->value_len to the length of the value. If the security module does not use security attributes or does not wish to put a security attribute on this particular inode, then it should return -EOPNOTSUPP to skip this processing.
Return
- Returns 0 if the LSM successfully initialized all of the inode
- security attributes that are required, negative values otherwise.
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int
security_path_mknod(const struct path *dir, struct dentry *dentry, umode_t mode, unsigned int dev)¶ Check if creating a special file is allowed
Parameters
const struct path *dir- parent directory
struct dentry *dentry- new file
umode_t mode- new file mode
unsigned int dev- device number
Description
Check permissions when creating a file. Note that this hook is called even if mknod operation is being done for a regular file.
Return
Returns 0 if permission is granted.
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int
security_path_mkdir(const struct path *dir, struct dentry *dentry, umode_t mode)¶ Check if creating a new directory is allowed
Parameters
const struct path *dir- parent directory
struct dentry *dentry- new directory
umode_t mode- new directory mode
Description
Check permissions to create a new directory in the existing directory.
Return
Returns 0 if permission is granted.
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int
security_path_unlink(const struct path *dir, struct dentry *dentry)¶ Check if removing a hard link is allowed
Parameters
const struct path *dir- parent directory
struct dentry *dentry- file
Description
Check the permission to remove a hard link to a file.
Return
Returns 0 if permission is granted.
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int
security_path_rename(const struct path *old_dir, struct dentry *old_dentry, const struct path *new_dir, struct dentry *new_dentry, unsigned int flags)¶ Check if renaming a file is allowed
Parameters
const struct path *old_dir- parent directory of the old file
struct dentry *old_dentry- the old file
const struct path *new_dir- parent directory of the new file
struct dentry *new_dentry- the new file
unsigned int flags- flags
Description
Check for permission to rename a file or directory.
Return
Returns 0 if permission is granted.
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int
security_inode_create(struct inode *dir, struct dentry *dentry, umode_t mode)¶ Check if creating a file is allowed
Parameters
struct inode *dir- the parent directory
struct dentry *dentry- the file being created
umode_t mode- requested file mode
Description
Check permission to create a regular file.
Return
Returns 0 if permission is granted.
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int
security_inode_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode)¶ Check if creation a new director is allowed
Parameters
struct inode *dir- parent directory
struct dentry *dentry- new directory
umode_t mode- new directory mode
Description
Check permissions to create a new directory in the existing directory associated with inode structure dir.
Return
Returns 0 if permission is granted.
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int
security_inode_setattr(struct mnt_idmap *idmap, struct dentry *dentry, struct iattr *attr)¶ Check if setting file attributes is allowed
Parameters
struct mnt_idmap *idmap- idmap of the mount
struct dentry *dentry- file
struct iattr *attr- new attributes
Description
Check permission before setting file attributes. Note that the kernel call to notify_change is performed from several locations, whenever file attributes change (such as when a file is truncated, chown/chmod operations, transferring disk quotas, etc).
Return
Returns 0 if permission is granted.
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int
security_inode_listsecurity(struct inode *inode, char *buffer, size_t buffer_size)¶ List the xattr security label names
Parameters
struct inode *inode- inode
char *buffer- buffer
size_t buffer_size- size of buffer
Description
Copy the extended attribute names for the security labels associated with inode into buffer. The maximum size of buffer is specified by buffer_size. buffer may be NULL to request the size of the buffer required.
Return
Returns number of bytes used/required on success.
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int
security_inode_copy_up(struct dentry *src, struct cred **new)¶ Create new creds for an overlayfs copy-up op
Parameters
struct dentry *src- union dentry of copy-up file
struct cred **new- newly created creds
Description
A file is about to be copied up from lower layer to upper layer of overlay filesystem. Security module can prepare a set of new creds and modify as need be and return new creds. Caller will switch to new creds temporarily to create new file and release newly allocated creds.
Return
Returns 0 on success or a negative error code on error.
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int
security_inode_copy_up_xattr(const char *name)¶ Filter xattrs in an overlayfs copy-up op
Parameters
const char *name- xattr name
Description
Filter the xattrs being copied up when a unioned file is copied up from a lower layer to the union/overlay layer. The caller is responsible for reading and writing the xattrs, this hook is merely a filter.
Return
- Returns 0 to accept the xattr, 1 to discard the xattr, -EOPNOTSUPP
- if the security module does not know about attribute, or a negative error code to abort the copy up.
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int
security_file_ioctl(struct file *file, unsigned int cmd, unsigned long arg)¶ Check if an ioctl is allowed
Parameters
struct file *file- associated file
unsigned int cmd- ioctl cmd
unsigned long arg- ioctl arguments
Description
Check permission for an ioctl operation on file. Note that arg sometimes represents a user space pointer; in other cases, it may be a simple integer value. When arg represents a user space pointer, it should never be used by the security module.
Return
Returns 0 if permission is granted.
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void
security_cred_getsecid(const struct cred *c, u32 *secid)¶ Get the secid from a set of credentials
Parameters
const struct cred *c- credentials
u32 *secid- secid value
Description
Retrieve the security identifier of the cred structure c. In case of failure, secid will be set to zero.
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int
security_kernel_read_file(struct file *file, enum kernel_read_file_id id, bool contents)¶ Read a file specified by userspace
Parameters
struct file *file- file
enum kernel_read_file_id id- file identifier
bool contents- trust if
security_kernel_post_read_file()will be called
Description
Read a file specified by userspace.
Return
Returns 0 if permission is granted.
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int
security_kernel_post_read_file(struct file *file, char *buf, loff_t size, enum kernel_read_file_id id)¶ Read a file specified by userspace
Parameters
struct file *file- file
char *buf- file contents
loff_t size- size of file contents
enum kernel_read_file_id id- file identifier
Description
Read a file specified by userspace. This must be paired with a prior call
to security_kernel_read_file() call that indicated this hook would also be
called, see security_kernel_read_file() for more information.
Return
Returns 0 if permission is granted.
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int
security_kernel_load_data(enum kernel_load_data_id id, bool contents)¶ Load data provided by userspace
Parameters
enum kernel_load_data_id id- data identifier
bool contents- true if
security_kernel_post_load_data()will be called
Description
Load data provided by userspace.
Return
Returns 0 if permission is granted.
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int
security_kernel_post_load_data(char *buf, loff_t size, enum kernel_load_data_id id, char *description)¶ Load userspace data from a non-file source
Parameters
char *buf- data
loff_t size- size of data
enum kernel_load_data_id id- data identifier
char *description- text description of data, specific to the id value
Description
Load data provided by a non-file source (usually userspace buffer). This
must be paired with a prior security_kernel_load_data() call that indicated
this hook would also be called, see security_kernel_load_data() for more
information.
Return
Returns 0 if permission is granted.
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void
security_current_getsecid_subj(u32 *secid)¶ Get the current task's subjective secid
Parameters
u32 *secid- secid value
Description
Retrieve the subjective security identifier of the current task and return it in secid. In case of failure, secid will be set to zero.
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void
security_task_getsecid_obj(struct task_struct *p, u32 *secid)¶ Get a task's objective secid
Parameters
struct task_struct *p- target task
u32 *secid- secid value
Description
Retrieve the objective security identifier of the task_struct in p and return it in secid. In case of failure, secid will be set to zero.
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void
security_d_instantiate(struct dentry *dentry, struct inode *inode)¶ Populate an inode's LSM state based on a dentry
Parameters
struct dentry *dentry- dentry
struct inode *inode- inode
Description
Fill in inode security information for a dentry if allowed.
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int
security_ismaclabel(const char *name)¶ Check is the named attribute is a MAC label
Parameters
const char *name- full extended attribute name
Description
Check if the extended attribute specified by name represents a MAC label.
Return
Returns 1 if name is a MAC attribute otherwise returns 0.
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int
security_secid_to_secctx(u32 secid, char **secdata, u32 *seclen)¶ Convert a secid to a secctx
Parameters
u32 secid- secid
char **secdata- secctx
u32 *seclen- secctx length
Description
Convert secid to security context. If secdata is NULL the length of the result will be returned in seclen, but no secdata will be returned. This does mean that the length could change between calls to check the length and the next call which actually allocates and returns the secdata.
Return
Return 0 on success, error on failure.
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int
security_secctx_to_secid(const char *secdata, u32 seclen, u32 *secid)¶ Convert a secctx to a secid
Parameters
const char *secdata- secctx
u32 seclen- length of secctx
u32 *secid- secid
Description
Convert security context to secid.
Return
Returns 0 on success, error on failure.
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void
security_release_secctx(char *secdata, u32 seclen)¶ Free a secctx buffer
Parameters
char *secdata- secctx
u32 seclen- length of secctx
Description
Release the security context.
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void
security_inode_invalidate_secctx(struct inode *inode)¶ Invalidate an inode's security label
Parameters
struct inode *inode- inode
Description
Notify the security module that it must revalidate the security context of an inode.
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int
security_inode_notifysecctx(struct inode *inode, void *ctx, u32 ctxlen)¶ Notify the LSM of an inode's security label
Parameters
struct inode *inode- inode
void *ctx- secctx
u32 ctxlen- length of secctx
Description
Notify the security module of what the security context of an inode should be. Initializes the incore security context managed by the security module for this inode. Example usage: NFS client invokes this hook to initialize the security context in its incore inode to the value provided by the server for the file when the server returned the file's attributes to the client. Must be called with inode->i_mutex locked.
Return
Returns 0 on success, error on failure.
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int
security_inode_setsecctx(struct dentry *dentry, void *ctx, u32 ctxlen)¶ Change the security label of an inode
Parameters
struct dentry *dentry- inode
void *ctx- secctx
u32 ctxlen- length of secctx
Description
Change the security context of an inode. Updates the incore security context managed by the security module and invokes the fs code as needed (via __vfs_setxattr_noperm) to update any backing xattrs that represent the context. Example usage: NFS server invokes this hook to change the security context in its incore inode and on the backing filesystem to a value provided by the client on a SETATTR operation. Must be called with inode->i_mutex locked.
Return
Returns 0 on success, error on failure.
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int
security_inode_getsecctx(struct inode *inode, void **ctx, u32 *ctxlen)¶ Get the security label of an inode
Parameters
struct inode *inode- inode
void **ctx- secctx
u32 *ctxlen- length of secctx
Description
On success, returns 0 and fills out ctx and ctxlen with the security context for the given inode.
Return
Returns 0 on success, error on failure.
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int
security_unix_stream_connect(struct sock *sock, struct sock *other, struct sock *newsk)¶ Check if a AF_UNIX stream is allowed
Parameters
struct sock *sock- originating sock
struct sock *other- peer sock
struct sock *newsk- new sock
Description
Check permissions before establishing a Unix domain stream connection between sock and other.
The unix_stream_connect and unix_may_send hooks were necessary because Linux provides an alternative to the conventional file name space for Unix domain sockets. Whereas binding and connecting to sockets in the file name space is mediated by the typical file permissions (and caught by the mknod and permission hooks in inode_security_ops), binding and connecting to sockets in the abstract name space is completely unmediated. Sufficient control of Unix domain sockets in the abstract name space isn't possible using only the socket layer hooks, since we need to know the actual target socket, which is not looked up until we are inside the af_unix code.
Return
Returns 0 if permission is granted.
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int
security_unix_may_send(struct socket *sock, struct socket *other)¶ Check if AF_UNIX socket can send datagrams
Parameters
struct socket *sock- originating sock
struct socket *other- peer sock
Description
Check permissions before connecting or sending datagrams from sock to other.
The unix_stream_connect and unix_may_send hooks were necessary because Linux provides an alternative to the conventional file name space for Unix domain sockets. Whereas binding and connecting to sockets in the file name space is mediated by the typical file permissions (and caught by the mknod and permission hooks in inode_security_ops), binding and connecting to sockets in the abstract name space is completely unmediated. Sufficient control of Unix domain sockets in the abstract name space isn't possible using only the socket layer hooks, since we need to know the actual target socket, which is not looked up until we are inside the af_unix code.
Return
Returns 0 if permission is granted.
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int
security_socket_socketpair(struct socket *socka, struct socket *sockb)¶ Check if creating a socketpair is allowed
Parameters
struct socket *socka- first socket
struct socket *sockb- second socket
Description
Check permissions before creating a fresh pair of sockets.
Return
- Returns 0 if permission is granted and the connection was
- established.
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int
security_sock_rcv_skb(struct sock *sk, struct sk_buff *skb)¶ Check if an incoming network packet is allowed
Parameters
struct sock *sk- destination sock
struct sk_buff *skb- incoming packet
Description
Check permissions on incoming network packets. This hook is distinct from Netfilter's IP input hooks since it is the first time that the incoming sk_buff skb has been associated with a particular socket, sk. Must not sleep inside this hook because some callers hold spinlocks.
Return
Returns 0 if permission is granted.
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int
security_socket_getpeersec_dgram(struct socket *sock, struct sk_buff *skb, u32 *secid)¶ Get the remote peer label
Parameters
struct socket *sock- socket
struct sk_buff *skb- datagram packet
u32 *secid- remote peer label secid
Description
This hook allows the security module to provide peer socket security state for udp sockets on a per-packet basis to userspace via getsockopt SO_GETPEERSEC. The application must first have indicated the IP_PASSSEC option via getsockopt. It can then retrieve the security state returned by this hook for a packet via the SCM_SECURITY ancillary message type.
Return
Returns 0 on success, error on failure.
Parameters
const struct sock *sk- original sock
struct sock *newsk- target sock
Description
Clone/copy security structure.
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void
security_sk_classify_flow(const struct sock *sk, struct flowi_common *flic)¶ Set a flow's secid based on socket
Parameters
const struct sock *sk- original socket
struct flowi_common *flic- target flow
Description
Set the target flow's secid to socket's secid.
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void
security_req_classify_flow(const struct request_sock *req, struct flowi_common *flic)¶ Set a flow's secid based on request_sock
Parameters
const struct request_sock *req- request_sock
struct flowi_common *flic- target flow
Description
Sets flic's secid to req's secid.
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void
security_sock_graft(struct sock *sk, struct socket *parent)¶ Reconcile LSM state when grafting a sock on a socket
Parameters
struct sock *sk- sock being grafted
struct socket *parent- target parent socket
Description
Sets parent's inode secid to sk's secid and update sk with any necessary LSM state from parent.
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int
security_inet_conn_request(const struct sock *sk, struct sk_buff *skb, struct request_sock *req)¶ Set request_sock state using incoming connect
Parameters
const struct sock *sk- parent listening sock
struct sk_buff *skb- incoming connection
struct request_sock *req- new request_sock
Description
Initialize the req LSM state based on sk and the incoming connect in skb.
Return
Returns 0 if permission is granted.
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void
security_inet_conn_established(struct sock *sk, struct sk_buff *skb)¶ Update sock's LSM state with connection
Parameters
struct sock *sk- sock
struct sk_buff *skb- connection packet
Description
Update sock's LSM state to represent a new connection from skb.
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int
security_secmark_relabel_packet(u32 secid)¶ Check if setting a secmark is allowed
Parameters
u32 secid- new secmark value
Description
Check if the process should be allowed to relabel packets to secid.
Return
Returns 0 if permission is granted.
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void
security_secmark_refcount_inc(void)¶ Increment the secmark labeling rule count
Parameters
void- no arguments
Description
Tells the LSM to increment the number of secmark labeling rules loaded.
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void
security_secmark_refcount_dec(void)¶ Decrement the secmark labeling rule count
Parameters
void- no arguments
Description
Tells the LSM to decrement the number of secmark labeling rules loaded.
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int
security_tun_dev_alloc_security(void **security)¶ Allocate a LSM blob for a TUN device
Parameters
void **security- pointer to the LSM blob
Description
This hook allows a module to allocate a security structure for a TUN device, returning the pointer in security.
Return
Returns a zero on success, negative values on failure.
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void
security_tun_dev_free_security(void *security)¶ Free a TUN device LSM blob
Parameters
void *security- LSM blob
Description
This hook allows a module to free the security structure for a TUN device.
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int
security_tun_dev_create(void)¶ Check if creating a TUN device is allowed
Parameters
void- no arguments
Description
Check permissions prior to creating a new TUN device.
Return
Returns 0 if permission is granted.
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int
security_tun_dev_attach_queue(void *security)¶ Check if attaching a TUN queue is allowed
Parameters
void *security- TUN device LSM blob
Description
Check permissions prior to attaching to a TUN device queue.
Return
Returns 0 if permission is granted.
Parameters
struct sock *sk- associated sock
void *security- TUN device LSM blob
Description
This hook can be used by the module to update any security state associated with the TUN device's sock structure.
Return
Returns 0 if permission is granted.
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int
security_tun_dev_open(void *security)¶ Update TUN device LSM state on open
Parameters
void *security- TUN device LSM blob
Description
This hook can be used by the module to update any security state associated with the TUN device's security structure.
Return
Returns 0 if permission is granted.
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int
security_sctp_assoc_request(struct sctp_association *asoc, struct sk_buff *skb)¶ Update the LSM on a SCTP association req
Parameters
struct sctp_association *asoc- SCTP association
struct sk_buff *skb- packet requesting the association
Description
Passes the asoc and chunk->skb of the association INIT packet to the LSM.
Return
Returns 0 on success, error on failure.
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int
security_sctp_bind_connect(struct sock *sk, int optname, struct sockaddr *address, int addrlen)¶ Validate a list of addrs for a SCTP option
Parameters
struct sock *sk- socket
int optname- SCTP option to validate
struct sockaddr *address- list of IP addresses to validate
int addrlen- length of the address list
Description
Validiate permissions required for each address associated with sock sk. Depending on optname, the addresses will be treated as either a connect or bind service. The addrlen is calculated on each IPv4 and IPv6 address using sizeof(struct sockaddr_in) or sizeof(struct sockaddr_in6).
Return
Returns 0 on success, error on failure.
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void
security_sctp_sk_clone(struct sctp_association *asoc, struct sock *sk, struct sock *newsk)¶ Clone a SCTP sock's LSM state
Parameters
struct sctp_association *asoc- SCTP association
struct sock *sk- original sock
struct sock *newsk- target sock
Description
Called whenever a new socket is created by accept(2) (i.e. a TCP style socket) or when a socket is 'peeled off' e.g userspace calls sctp_peeloff(3).
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int
security_sctp_assoc_established(struct sctp_association *asoc, struct sk_buff *skb)¶ Update LSM state when assoc established
Parameters
struct sctp_association *asoc- SCTP association
struct sk_buff *skb- packet establishing the association
Description
Passes the asoc and chunk->skb of the association COOKIE_ACK packet to the security module.
Return
Returns 0 if permission is granted.
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int
security_ib_pkey_access(void *sec, u64 subnet_prefix, u16 pkey)¶ Check if access to an IB pkey is allowed
Parameters
void *sec- LSM blob
u64 subnet_prefix- subnet prefix of the port
u16 pkey- IB pkey
Description
Check permission to access a pkey when modifying a QP.
Return
Returns 0 if permission is granted.
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int
security_ib_endport_manage_subnet(void *sec, const char *dev_name, u8 port_num)¶ Check if SMPs traffic is allowed
Parameters
void *sec- LSM blob
const char *dev_name- IB device name
u8 port_num- port number
Description
Check permissions to send and receive SMPs on a end port.
Return
Returns 0 if permission is granted.
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int
security_ib_alloc_security(void **sec)¶ Allocate an Infiniband LSM blob
Parameters
void **sec- LSM blob
Description
Allocate a security structure for Infiniband objects.
Return
Returns 0 on success, non-zero on failure.
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void
security_ib_free_security(void *sec)¶ Free an Infiniband LSM blob
Parameters
void *sec- LSM blob
Description
Deallocate an Infiniband security structure.
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int
security_xfrm_policy_alloc(struct xfrm_sec_ctx **ctxp, struct xfrm_user_sec_ctx *sec_ctx, gfp_t gfp)¶ Allocate a xfrm policy LSM blob
Parameters
struct xfrm_sec_ctx **ctxp- xfrm security context being added to the SPD
struct xfrm_user_sec_ctx *sec_ctx- security label provided by userspace
gfp_t gfp- gfp flags
Description
Allocate a security structure to the xp->security field; the security field is initialized to NULL when the xfrm_policy is allocated.
Return
Return 0 if operation was successful.
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void
security_xfrm_policy_free(struct xfrm_sec_ctx *ctx)¶ Free a xfrm security context
Parameters
struct xfrm_sec_ctx *ctx- xfrm security context
Description
Free LSM resources associated with ctx.
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int
security_xfrm_state_alloc(struct xfrm_state *x, struct xfrm_user_sec_ctx *sec_ctx)¶ Allocate a xfrm state LSM blob
Parameters
struct xfrm_state *x- xfrm state being added to the SAD
struct xfrm_user_sec_ctx *sec_ctx- security label provided by userspace
Description
Allocate a security structure to the x->security field; the security field is initialized to NULL when the xfrm_state is allocated. Set the context to correspond to sec_ctx.
Return
Return 0 if operation was successful.
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int
security_xfrm_state_delete(struct xfrm_state *x)¶ Check if deleting a xfrm state is allowed
Parameters
struct xfrm_state *x- xfrm state
Description
Authorize deletion of x->security.
Return
Returns 0 if permission is granted.
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int
security_locked_down(enum lockdown_reason what)¶ Check if a kernel feature is allowed
Parameters
enum lockdown_reason what- requested kernel feature
Description
Determine whether a kernel feature that potentially enables arbitrary code execution in kernel space should be permitted.
Return
Returns 0 if permission is granted.