forked from Minki/linux
CRED: Prettify commoncap.c
Prettify commoncap.c. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Serge Hallyn <serue@us.ibm.com> Reviewed-by: James Morris <jmorris@namei.org> Signed-off-by: James Morris <jmorris@namei.org>
This commit is contained in:
David Howells
James Morris
parent
a6f76f23d2
commit
1d045980e1
@ -40,14 +40,21 @@ int cap_netlink_recv(struct sk_buff *skb, int cap)
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return -EPERM;
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return 0;
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}
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EXPORT_SYMBOL(cap_netlink_recv);
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/*
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/**
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* cap_capable - Determine whether a task has a particular effective capability
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* @tsk: The task to query
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* @cap: The capability to check for
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* @audit: Whether to write an audit message or not
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*
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* Determine whether the nominated task has the specified capability amongst
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* its effective set, returning 0 if it does, -ve if it does not.
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*
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* NOTE WELL: cap_capable() cannot be used like the kernel's capable()
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* function. That is, it has the reverse semantics: cap_capable()
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* returns 0 when a task has a capability, but the kernel's capable()
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* returns 1 for this case.
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* function. That is, it has the reverse semantics: cap_capable() returns 0
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* when a task has a capability, but the kernel's capable() returns 1 for this
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* case.
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*/
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int cap_capable(struct task_struct *tsk, int cap, int audit)
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{
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@ -60,6 +67,14 @@ int cap_capable(struct task_struct *tsk, int cap, int audit)
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return cap_raised ? 0 : -EPERM;
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}
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/**
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* cap_settime - Determine whether the current process may set the system clock
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* @ts: The time to set
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* @tz: The timezone to set
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*
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* Determine whether the current process may set the system clock and timezone
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* information, returning 0 if permission granted, -ve if denied.
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*/
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int cap_settime(struct timespec *ts, struct timezone *tz)
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{
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if (!capable(CAP_SYS_TIME))
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@ -67,6 +82,15 @@ int cap_settime(struct timespec *ts, struct timezone *tz)
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return 0;
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}
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/**
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* cap_ptrace_may_access - Determine whether the current process may access
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* another
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* @child: The process to be accessed
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* @mode: The mode of attachment.
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*
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* Determine whether a process may access another, returning 0 if permission
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* granted, -ve if denied.
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*/
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int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
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{
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int ret = 0;
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@ -80,6 +104,13 @@ int cap_ptrace_may_access(struct task_struct *child, unsigned int mode)
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return ret;
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}
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/**
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* cap_ptrace_traceme - Determine whether another process may trace the current
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* @parent: The task proposed to be the tracer
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*
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* Determine whether the nominated task is permitted to trace the current
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* process, returning 0 if permission is granted, -ve if denied.
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*/
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int cap_ptrace_traceme(struct task_struct *parent)
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{
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int ret = 0;
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@ -93,8 +124,18 @@ int cap_ptrace_traceme(struct task_struct *parent)
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return ret;
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}
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int cap_capget (struct task_struct *target, kernel_cap_t *effective,
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kernel_cap_t *inheritable, kernel_cap_t *permitted)
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/**
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* cap_capget - Retrieve a task's capability sets
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* @target: The task from which to retrieve the capability sets
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* @effective: The place to record the effective set
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* @inheritable: The place to record the inheritable set
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* @permitted: The place to record the permitted set
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*
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* This function retrieves the capabilities of the nominated task and returns
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* them to the caller.
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*/
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int cap_capget(struct task_struct *target, kernel_cap_t *effective,
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kernel_cap_t *inheritable, kernel_cap_t *permitted)
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{
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const struct cred *cred;
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@ -108,30 +149,35 @@ int cap_capget (struct task_struct *target, kernel_cap_t *effective,
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return 0;
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}
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#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
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/*
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* Determine whether the inheritable capabilities are limited to the old
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* permitted set. Returns 1 if they are limited, 0 if they are not.
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*/
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static inline int cap_inh_is_capped(void)
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{
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/*
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* Return 1 if changes to the inheritable set are limited
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* to the old permitted set. That is, if the current task
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* does *not* possess the CAP_SETPCAP capability.
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#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
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/* they are so limited unless the current task has the CAP_SETPCAP
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* capability
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*/
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return cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0;
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if (cap_capable(current, CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0)
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return 0;
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#endif
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return 1;
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}
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static inline int cap_limit_ptraced_target(void) { return 1; }
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#else /* ie., ndef CONFIG_SECURITY_FILE_CAPABILITIES */
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static inline int cap_inh_is_capped(void) { return 1; }
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static inline int cap_limit_ptraced_target(void)
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{
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return !capable(CAP_SETPCAP);
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}
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#endif /* def CONFIG_SECURITY_FILE_CAPABILITIES */
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/**
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* cap_capset - Validate and apply proposed changes to current's capabilities
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* @new: The proposed new credentials; alterations should be made here
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* @old: The current task's current credentials
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* @effective: A pointer to the proposed new effective capabilities set
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* @inheritable: A pointer to the proposed new inheritable capabilities set
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* @permitted: A pointer to the proposed new permitted capabilities set
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*
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* This function validates and applies a proposed mass change to the current
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* process's capability sets. The changes are made to the proposed new
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* credentials, and assuming no error, will be committed by the caller of LSM.
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*/
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int cap_capset(struct cred *new,
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const struct cred *old,
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const kernel_cap_t *effective,
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@ -165,6 +211,9 @@ int cap_capset(struct cred *new,
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return 0;
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}
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/*
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* Clear proposed capability sets for execve().
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*/
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static inline void bprm_clear_caps(struct linux_binprm *bprm)
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{
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cap_clear(bprm->cred->cap_permitted);
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@ -173,6 +222,17 @@ static inline void bprm_clear_caps(struct linux_binprm *bprm)
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#ifdef CONFIG_SECURITY_FILE_CAPABILITIES
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/**
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* cap_inode_need_killpriv - Determine if inode change affects privileges
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* @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV
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*
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* Determine if an inode having a change applied that's marked ATTR_KILL_PRIV
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* affects the security markings on that inode, and if it is, should
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* inode_killpriv() be invoked or the change rejected?
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*
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* Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and
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* -ve to deny the change.
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*/
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int cap_inode_need_killpriv(struct dentry *dentry)
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{
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struct inode *inode = dentry->d_inode;
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@ -187,6 +247,14 @@ int cap_inode_need_killpriv(struct dentry *dentry)
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return 1;
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}
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/**
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* cap_inode_killpriv - Erase the security markings on an inode
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* @dentry: The inode/dentry to alter
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*
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* Erase the privilege-enhancing security markings on an inode.
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*
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* Returns 0 if successful, -ve on error.
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*/
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int cap_inode_killpriv(struct dentry *dentry)
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{
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struct inode *inode = dentry->d_inode;
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@ -197,6 +265,10 @@ int cap_inode_killpriv(struct dentry *dentry)
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return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS);
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}
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/*
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* Calculate the new process capability sets from the capability sets attached
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* to a file.
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*/
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static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
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struct linux_binprm *bprm,
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bool *effective)
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@ -232,6 +304,9 @@ static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps,
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return *effective ? ret : 0;
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}
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/*
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* Extract the on-exec-apply capability sets for an executable file.
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*/
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int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps)
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{
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struct inode *inode = dentry->d_inode;
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@ -283,7 +358,11 @@ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data
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return 0;
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}
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/* Locate any VFS capabilities: */
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/*
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* Attempt to get the on-exec apply capability sets for an executable file from
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* its xattrs and, if present, apply them to the proposed credentials being
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* constructed by execve().
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*/
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static int get_file_caps(struct linux_binprm *bprm, bool *effective)
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{
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struct dentry *dentry;
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@ -342,7 +421,31 @@ static inline int get_file_caps(struct linux_binprm *bprm, bool *effective)
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#endif
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/*
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* set up the new credentials for an exec'd task
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* Determine whether a exec'ing process's new permitted capabilities should be
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* limited to just what it already has.
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*
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* This prevents processes that are being ptraced from gaining access to
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* CAP_SETPCAP, unless the process they're tracing already has it, and the
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* binary they're executing has filecaps that elevate it.
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*
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* Returns 1 if they should be limited, 0 if they are not.
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*/
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static inline int cap_limit_ptraced_target(void)
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{
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#ifndef CONFIG_SECURITY_FILE_CAPABILITIES
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if (capable(CAP_SETPCAP))
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return 0;
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#endif
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return 1;
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}
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/**
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* cap_bprm_set_creds - Set up the proposed credentials for execve().
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* @bprm: The execution parameters, including the proposed creds
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*
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* Set up the proposed credentials for a new execution context being
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* constructed by execve(). The proposed creds in @bprm->cred is altered,
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* which won't take effect immediately. Returns 0 if successful, -ve on error.
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*/
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int cap_bprm_set_creds(struct linux_binprm *bprm)
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{
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@ -430,10 +533,15 @@ int cap_bprm_set_creds(struct linux_binprm *bprm)
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return 0;
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}
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/*
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* determine whether a secure execution is required
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* - the creds have been committed at this point, and are no longer available
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* through bprm
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/**
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* cap_bprm_secureexec - Determine whether a secure execution is required
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* @bprm: The execution parameters
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*
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* Determine whether a secure execution is required, return 1 if it is, and 0
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* if it is not.
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*
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* The credentials have been committed by this point, and so are no longer
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* available through @bprm->cred.
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*/
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int cap_bprm_secureexec(struct linux_binprm *bprm)
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{
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@ -450,6 +558,20 @@ int cap_bprm_secureexec(struct linux_binprm *bprm)
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cred->egid != cred->gid);
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}
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/**
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* cap_inode_setxattr - Determine whether an xattr may be altered
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* @dentry: The inode/dentry being altered
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* @name: The name of the xattr to be changed
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* @value: The value that the xattr will be changed to
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* @size: The size of value
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* @flags: The replacement flag
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*
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* Determine whether an xattr may be altered or set on an inode, returning 0 if
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* permission is granted, -ve if denied.
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*
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* This is used to make sure security xattrs don't get updated or set by those
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* who aren't privileged to do so.
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*/
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int cap_inode_setxattr(struct dentry *dentry, const char *name,
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const void *value, size_t size, int flags)
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{
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@ -457,27 +579,41 @@ int cap_inode_setxattr(struct dentry *dentry, const char *name,
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if (!capable(CAP_SETFCAP))
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return -EPERM;
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return 0;
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} else if (!strncmp(name, XATTR_SECURITY_PREFIX,
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}
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if (!strncmp(name, XATTR_SECURITY_PREFIX,
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sizeof(XATTR_SECURITY_PREFIX) - 1) &&
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!capable(CAP_SYS_ADMIN))
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return -EPERM;
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return 0;
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}
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/**
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* cap_inode_removexattr - Determine whether an xattr may be removed
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* @dentry: The inode/dentry being altered
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* @name: The name of the xattr to be changed
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*
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* Determine whether an xattr may be removed from an inode, returning 0 if
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* permission is granted, -ve if denied.
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*
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* This is used to make sure security xattrs don't get removed by those who
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* aren't privileged to remove them.
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*/
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int cap_inode_removexattr(struct dentry *dentry, const char *name)
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{
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if (!strcmp(name, XATTR_NAME_CAPS)) {
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if (!capable(CAP_SETFCAP))
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return -EPERM;
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return 0;
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} else if (!strncmp(name, XATTR_SECURITY_PREFIX,
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}
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if (!strncmp(name, XATTR_SECURITY_PREFIX,
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sizeof(XATTR_SECURITY_PREFIX) - 1) &&
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!capable(CAP_SYS_ADMIN))
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return -EPERM;
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return 0;
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}
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/* moved from kernel/sys.c. */
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/*
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* cap_emulate_setxuid() fixes the effective / permitted capabilities of
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* a process after a call to setuid, setreuid, or setresuid.
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@ -521,35 +657,46 @@ static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old)
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new->cap_effective = new->cap_permitted;
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}
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/**
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* cap_task_fix_setuid - Fix up the results of setuid() call
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* @new: The proposed credentials
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* @old: The current task's current credentials
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* @flags: Indications of what has changed
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*
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* Fix up the results of setuid() call before the credential changes are
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* actually applied, returning 0 to grant the changes, -ve to deny them.
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*/
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int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags)
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{
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switch (flags) {
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case LSM_SETID_RE:
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case LSM_SETID_ID:
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case LSM_SETID_RES:
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/* Copied from kernel/sys.c:setreuid/setuid/setresuid. */
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/* juggle the capabilities to follow [RES]UID changes unless
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* otherwise suppressed */
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if (!issecure(SECURE_NO_SETUID_FIXUP))
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cap_emulate_setxuid(new, old);
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break;
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case LSM_SETID_FS:
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/* Copied from kernel/sys.c:setfsuid. */
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/*
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case LSM_SETID_FS:
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/* juggle the capabilties to follow FSUID changes, unless
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* otherwise suppressed
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*
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* FIXME - is fsuser used for all CAP_FS_MASK capabilities?
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* if not, we might be a bit too harsh here.
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*/
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if (!issecure(SECURE_NO_SETUID_FIXUP)) {
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if (old->fsuid == 0 && new->fsuid != 0) {
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if (old->fsuid == 0 && new->fsuid != 0)
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new->cap_effective =
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cap_drop_fs_set(new->cap_effective);
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}
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if (old->fsuid != 0 && new->fsuid == 0) {
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if (old->fsuid != 0 && new->fsuid == 0)
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new->cap_effective =
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cap_raise_fs_set(new->cap_effective,
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new->cap_permitted);
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}
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}
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break;
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default:
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return -EINVAL;
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}
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@ -582,28 +729,50 @@ static int cap_safe_nice(struct task_struct *p)
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return 0;
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}
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int cap_task_setscheduler (struct task_struct *p, int policy,
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/**
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* cap_task_setscheduler - Detemine if scheduler policy change is permitted
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* @p: The task to affect
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* @policy: The policy to effect
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* @lp: The parameters to the scheduling policy
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*
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* Detemine if the requested scheduler policy change is permitted for the
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* specified task, returning 0 if permission is granted, -ve if denied.
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*/
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int cap_task_setscheduler(struct task_struct *p, int policy,
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struct sched_param *lp)
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{
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return cap_safe_nice(p);
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}
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int cap_task_setioprio (struct task_struct *p, int ioprio)
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/**
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* cap_task_ioprio - Detemine if I/O priority change is permitted
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* @p: The task to affect
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* @ioprio: The I/O priority to set
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*
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* Detemine if the requested I/O priority change is permitted for the specified
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* task, returning 0 if permission is granted, -ve if denied.
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*/
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int cap_task_setioprio(struct task_struct *p, int ioprio)
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{
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return cap_safe_nice(p);
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}
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int cap_task_setnice (struct task_struct *p, int nice)
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/**
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* cap_task_ioprio - Detemine if task priority change is permitted
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* @p: The task to affect
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* @nice: The nice value to set
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*
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* Detemine if the requested task priority change is permitted for the
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* specified task, returning 0 if permission is granted, -ve if denied.
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*/
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int cap_task_setnice(struct task_struct *p, int nice)
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{
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return cap_safe_nice(p);
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}
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/*
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* called from kernel/sys.c for prctl(PR_CABSET_DROP)
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* done without task_capability_lock() because it introduces
|
||||
* no new races - i.e. only another task doing capget() on
|
||||
* this task could get inconsistent info. There can be no
|
||||
* racing writer bc a task can only change its own caps.
|
||||
* Implement PR_CAPBSET_DROP. Attempt to remove the specified capability from
|
||||
* the current task's bounding set. Returns 0 on success, -ve on error.
|
||||
*/
|
||||
static long cap_prctl_drop(struct cred *new, unsigned long cap)
|
||||
{
|
||||
@ -632,6 +801,18 @@ int cap_task_setnice (struct task_struct *p, int nice)
|
||||
}
|
||||
#endif
|
||||
|
||||
/**
|
||||
* cap_task_prctl - Implement process control functions for this security module
|
||||
* @option: The process control function requested
|
||||
* @arg2, @arg3, @arg4, @arg5: The argument data for this function
|
||||
*
|
||||
* Allow process control functions (sys_prctl()) to alter capabilities; may
|
||||
* also deny access to other functions not otherwise implemented here.
|
||||
*
|
||||
* Returns 0 or +ve on success, -ENOSYS if this function is not implemented
|
||||
* here, other -ve on error. If -ENOSYS is returned, sys_prctl() and other LSM
|
||||
* modules will consider performing the function.
|
||||
*/
|
||||
int cap_task_prctl(int option, unsigned long arg2, unsigned long arg3,
|
||||
unsigned long arg4, unsigned long arg5)
|
||||
{
|
||||
@ -737,13 +918,28 @@ error:
|
||||
return error;
|
||||
}
|
||||
|
||||
int cap_syslog (int type)
|
||||
/**
|
||||
* cap_syslog - Determine whether syslog function is permitted
|
||||
* @type: Function requested
|
||||
*
|
||||
* Determine whether the current process is permitted to use a particular
|
||||
* syslog function, returning 0 if permission is granted, -ve if not.
|
||||
*/
|
||||
int cap_syslog(int type)
|
||||
{
|
||||
if ((type != 3 && type != 10) && !capable(CAP_SYS_ADMIN))
|
||||
return -EPERM;
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* cap_vm_enough_memory - Determine whether a new virtual mapping is permitted
|
||||
* @mm: The VM space in which the new mapping is to be made
|
||||
* @pages: The size of the mapping
|
||||
*
|
||||
* Determine whether the allocation of a new virtual mapping by the current
|
||||
* task is permitted, returning 0 if permission is granted, -ve if not.
|
||||
*/
|
||||
int cap_vm_enough_memory(struct mm_struct *mm, long pages)
|
||||
{
|
||||
int cap_sys_admin = 0;
|
||||
|
||||
Loading…
Reference in New Issue
Block a user