/* Common capabilities, needed by capability.o. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * If a non-root user executes a setuid-root binary in * !secure(SECURE_NOROOT) mode, then we raise capabilities. * However if fE is also set, then the intent is for only * the file capabilities to be applied, and the setuid-root * bit is left on either to change the uid (plausible) or * to get full privilege on a kernel without file capabilities * support. So in that case we do not raise capabilities. * * Warn if that happens, once per boot. */ static void warn_setuid_and_fcaps_mixed(const char *fname) { static int warned; if (!warned) { printk(KERN_INFO "warning: `%s' has both setuid-root and" " effective capabilities. Therefore not raising all" " capabilities.\n", fname); warned = 1; } } int cap_netlink_send(struct sock *sk, struct sk_buff *skb) { return 0; } int cap_netlink_recv(struct sk_buff *skb, int cap) { if (!cap_raised(current_cap(), cap)) return -EPERM; return 0; } EXPORT_SYMBOL(cap_netlink_recv); /** * cap_capable - Determine whether a task has a particular effective capability * @tsk: The task to query * @cred: The credentials to use * @ns: The user namespace in which we need the capability * @cap: The capability to check for * @audit: Whether to write an audit message or not * * Determine whether the nominated task has the specified capability amongst * its effective set, returning 0 if it does, -ve if it does not. * * NOTE WELL: cap_has_capability() cannot be used like the kernel's capable() * and has_capability() functions. That is, it has the reverse semantics: * cap_has_capability() returns 0 when a task has a capability, but the * kernel's capable() and has_capability() returns 1 for this case. */ int cap_capable(struct task_struct *tsk, const struct cred *cred, struct user_namespace *targ_ns, int cap, int audit) { for (;;) { /* The creator of the user namespace has all caps. */ if (targ_ns != &init_user_ns && targ_ns->creator == cred->user) return 0; /* Do we have the necessary capabilities? */ if (targ_ns == cred->user->user_ns) return cap_raised(cred->cap_effective, cap) ? 0 : -EPERM; /* Have we tried all of the parent namespaces? */ if (targ_ns == &init_user_ns) return -EPERM; /* *If you have a capability in a parent user ns, then you have * it over all children user namespaces as well. */ targ_ns = targ_ns->creator->user_ns; } /* We never get here */ } /** * cap_settime - Determine whether the current process may set the system clock * @ts: The time to set * @tz: The timezone to set * * Determine whether the current process may set the system clock and timezone * information, returning 0 if permission granted, -ve if denied. */ int cap_settime(const struct timespec *ts, const struct timezone *tz) { if (!capable(CAP_SYS_TIME)) return -EPERM; return 0; } /** * cap_ptrace_access_check - Determine whether the current process may access * another * @child: The process to be accessed * @mode: The mode of attachment. * * If we are in the same or an ancestor user_ns and have all the target * task's capabilities, then ptrace access is allowed. * If we have the ptrace capability to the target user_ns, then ptrace * access is allowed. * Else denied. * * Determine whether a process may access another, returning 0 if permission * granted, -ve if denied. */ int cap_ptrace_access_check(struct task_struct *child, unsigned int mode) { int ret = 0; const struct cred *cred, *child_cred; rcu_read_lock(); cred = current_cred(); child_cred = __task_cred(child); if (cred->user->user_ns == child_cred->user->user_ns && cap_issubset(child_cred->cap_permitted, cred->cap_permitted)) goto out; if (ns_capable(child_cred->user->user_ns, CAP_SYS_PTRACE)) goto out; ret = -EPERM; out: rcu_read_unlock(); return ret; } /** * cap_ptrace_traceme - Determine whether another process may trace the current * @parent: The task proposed to be the tracer * * If parent is in the same or an ancestor user_ns and has all current's * capabilities, then ptrace access is allowed. * If parent has the ptrace capability to current's user_ns, then ptrace * access is allowed. * Else denied. * * Determine whether the nominated task is permitted to trace the current * process, returning 0 if permission is granted, -ve if denied. */ int cap_ptrace_traceme(struct task_struct *parent) { int ret = 0; const struct cred *cred, *child_cred; rcu_read_lock(); cred = __task_cred(parent); child_cred = current_cred(); if (cred->user->user_ns == child_cred->user->user_ns && cap_issubset(child_cred->cap_permitted, cred->cap_permitted)) goto out; if (has_ns_capability(parent, child_cred->user->user_ns, CAP_SYS_PTRACE)) goto out; ret = -EPERM; out: rcu_read_unlock(); return ret; } /** * cap_capget - Retrieve a task's capability sets * @target: The task from which to retrieve the capability sets * @effective: The place to record the effective set * @inheritable: The place to record the inheritable set * @permitted: The place to record the permitted set * * This function retrieves the capabilities of the nominated task and returns * them to the caller. */ int cap_capget(struct task_struct *target, kernel_cap_t *effective, kernel_cap_t *inheritable, kernel_cap_t *permitted) { const struct cred *cred; /* Derived from kernel/capability.c:sys_capget. */ rcu_read_lock(); cred = __task_cred(target); *effective = cred->cap_effective; *inheritable = cred->cap_inheritable; *permitted = cred->cap_permitted; rcu_read_unlock(); return 0; } /* * Determine whether the inheritable capabilities are limited to the old * permitted set. Returns 1 if they are limited, 0 if they are not. */ static inline int cap_inh_is_capped(void) { /* they are so limited unless the current task has the CAP_SETPCAP * capability */ if (cap_capable(current, current_cred(), current_cred()->user->user_ns, CAP_SETPCAP, SECURITY_CAP_AUDIT) == 0) return 0; return 1; } /** * cap_capset - Validate and apply proposed changes to current's capabilities * @new: The proposed new credentials; alterations should be made here * @old: The current task's current credentials * @effective: A pointer to the proposed new effective capabilities set * @inheritable: A pointer to the proposed new inheritable capabilities set * @permitted: A pointer to the proposed new permitted capabilities set * * This function validates and applies a proposed mass change to the current * process's capability sets. The changes are made to the proposed new * credentials, and assuming no error, will be committed by the caller of LSM. */ int cap_capset(struct cred *new, const struct cred *old, const kernel_cap_t *effective, const kernel_cap_t *inheritable, const kernel_cap_t *permitted) { if (cap_inh_is_capped() && !cap_issubset(*inheritable, cap_combine(old->cap_inheritable, old->cap_permitted))) /* incapable of using this inheritable set */ return -EPERM; if (!cap_issubset(*inheritable, cap_combine(old->cap_inheritable, old->cap_bset))) /* no new pI capabilities outside bounding set */ return -EPERM; /* verify restrictions on target's new Permitted set */ if (!cap_issubset(*permitted, old->cap_permitted)) return -EPERM; /* verify the _new_Effective_ is a subset of the _new_Permitted_ */ if (!cap_issubset(*effective, *permitted)) return -EPERM; new->cap_effective = *effective; new->cap_inheritable = *inheritable; new->cap_permitted = *permitted; return 0; } /* * Clear proposed capability sets for execve(). */ static inline void bprm_clear_caps(struct linux_binprm *bprm) { cap_clear(bprm->cred->cap_permitted); bprm->cap_effective = false; } /** * cap_inode_need_killpriv - Determine if inode change affects privileges * @dentry: The inode/dentry in being changed with change marked ATTR_KILL_PRIV * * Determine if an inode having a change applied that's marked ATTR_KILL_PRIV * affects the security markings on that inode, and if it is, should * inode_killpriv() be invoked or the change rejected? * * Returns 0 if granted; +ve if granted, but inode_killpriv() is required; and * -ve to deny the change. */ int cap_inode_need_killpriv(struct dentry *dentry) { struct inode *inode = dentry->d_inode; int error; if (!inode->i_op->getxattr) return 0; error = inode->i_op->getxattr(dentry, XATTR_NAME_CAPS, NULL, 0); if (error <= 0) return 0; return 1; } /** * cap_inode_killpriv - Erase the security markings on an inode * @dentry: The inode/dentry to alter * * Erase the privilege-enhancing security markings on an inode. * * Returns 0 if successful, -ve on error. */ int cap_inode_killpriv(struct dentry *dentry) { struct inode *inode = dentry->d_inode; if (!inode->i_op->removexattr) return 0; return inode->i_op->removexattr(dentry, XATTR_NAME_CAPS); } /* * Calculate the new process capability sets from the capability sets attached * to a file. */ static inline int bprm_caps_from_vfs_caps(struct cpu_vfs_cap_data *caps, struct linux_binprm *bprm, bool *effective) { struct cred *new = bprm->cred; unsigned i; int ret = 0; if (caps->magic_etc & VFS_CAP_FLAGS_EFFECTIVE) *effective = true; CAP_FOR_EACH_U32(i) { __u32 permitted = caps->permitted.cap[i]; __u32 inheritable = caps->inheritable.cap[i]; /* * pP' = (X & fP) | (pI & fI) */ new->cap_permitted.cap[i] = (new->cap_bset.cap[i] & permitted) | (new->cap_inheritable.cap[i] & inheritable); if (permitted & ~new->cap_permitted.cap[i]) /* insufficient to execute correctly */ ret = -EPERM; } /* * For legacy apps, with no internal support for recognizing they * do not have enough capabilities, we return an error if they are * missing some "forced" (aka file-permitted) capabilities. */ return *effective ? ret : 0; } /* * Extract the on-exec-apply capability sets for an executable file. */ int get_vfs_caps_from_disk(const struct dentry *dentry, struct cpu_vfs_cap_data *cpu_caps) { struct inode *inode = dentry->d_inode; __u32 magic_etc; unsigned tocopy, i; int size; struct vfs_cap_data caps; memset(cpu_caps, 0, sizeof(struct cpu_vfs_cap_data)); if (!inode || !inode->i_op->getxattr) return -ENODATA; size = inode->i_op->getxattr((struct dentry *)dentry, XATTR_NAME_CAPS, &caps, XATTR_CAPS_SZ); if (size == -ENODATA || size == -EOPNOTSUPP) /* no data, that's ok */ return -ENODATA; if (size < 0) return size; if (size < sizeof(magic_etc)) return -EINVAL; cpu_caps->magic_etc = magic_etc = le32_to_cpu(caps.magic_etc); switch (magic_etc & VFS_CAP_REVISION_MASK) { case VFS_CAP_REVISION_1: if (size != XATTR_CAPS_SZ_1) return -EINVAL; tocopy = VFS_CAP_U32_1; break; case VFS_CAP_REVISION_2: if (size != XATTR_CAPS_SZ_2) return -EINVAL; tocopy = VFS_CAP_U32_2; break; default: return -EINVAL; } CAP_FOR_EACH_U32(i) { if (i >= tocopy) break; cpu_caps->permitted.cap[i] = le32_to_cpu(caps.data[i].permitted); cpu_caps->inheritable.cap[i] = le32_to_cpu(caps.data[i].inheritable); } return 0; } /* * Attempt to get the on-exec apply capability sets for an executable file from * its xattrs and, if present, apply them to the proposed credentials being * constructed by execve(). */ static int get_file_caps(struct linux_binprm *bprm, bool *effective) { struct dentry *dentry; int rc = 0; struct cpu_vfs_cap_data vcaps; bprm_clear_caps(bprm); if (!file_caps_enabled) return 0; if (bprm->file->f_vfsmnt->mnt_flags & MNT_NOSUID) return 0; dentry = dget(bprm->file->f_dentry); rc = get_vfs_caps_from_disk(dentry, &vcaps); if (rc < 0) { if (rc == -EINVAL) printk(KERN_NOTICE "%s: get_vfs_caps_from_disk returned %d for %s\n", __func__, rc, bprm->filename); else if (rc == -ENODATA) rc = 0; goto out; } rc = bprm_caps_from_vfs_caps(&vcaps, bprm, effective); if (rc == -EINVAL) printk(KERN_NOTICE "%s: cap_from_disk returned %d for %s\n", __func__, rc, bprm->filename); out: dput(dentry); if (rc) bprm_clear_caps(bprm); return rc; } /** * cap_bprm_set_creds - Set up the proposed credentials for execve(). * @bprm: The execution parameters, including the proposed creds * * Set up the proposed credentials for a new execution context being * constructed by execve(). The proposed creds in @bprm->cred is altered, * which won't take effect immediately. Returns 0 if successful, -ve on error. */ int cap_bprm_set_creds(struct linux_binprm *bprm) { const struct cred *old = current_cred(); struct cred *new = bprm->cred; bool effective; int ret; effective = false; ret = get_file_caps(bprm, &effective); if (ret < 0) return ret; if (!issecure(SECURE_NOROOT)) { /* * If the legacy file capability is set, then don't set privs * for a setuid root binary run by a non-root user. Do set it * for a root user just to cause least surprise to an admin. */ if (effective && new->uid != 0 && new->euid == 0) { warn_setuid_and_fcaps_mixed(bprm->filename); goto skip; } /* * To support inheritance of root-permissions and suid-root * executables under compatibility mode, we override the * capability sets for the file. * * If only the real uid is 0, we do not set the effective bit. */ if (new->euid == 0 || new->uid == 0) { /* pP' = (cap_bset & ~0) | (pI & ~0) */ new->cap_permitted = cap_combine(old->cap_bset, old->cap_inheritable); } if (new->euid == 0) effective = true; } skip: /* Don't let someone trace a set[ug]id/setpcap binary with the revised * credentials unless they have the appropriate permit */ if ((new->euid != old->uid || new->egid != old->gid || !cap_issubset(new->cap_permitted, old->cap_permitted)) && bprm->unsafe & ~LSM_UNSAFE_PTRACE_CAP) { /* downgrade; they get no more than they had, and maybe less */ if (!capable(CAP_SETUID)) { new->euid = new->uid; new->egid = new->gid; } new->cap_permitted = cap_intersect(new->cap_permitted, old->cap_permitted); } new->suid = new->fsuid = new->euid; new->sgid = new->fsgid = new->egid; if (effective) new->cap_effective = new->cap_permitted; else cap_clear(new->cap_effective); bprm->cap_effective = effective; /* * Audit candidate if current->cap_effective is set * * We do not bother to audit if 3 things are true: * 1) cap_effective has all caps * 2) we are root * 3) root is supposed to have all caps (SECURE_NOROOT) * Since this is just a normal root execing a process. * * Number 1 above might fail if you don't have a full bset, but I think * that is interesting information to audit. */ if (!cap_isclear(new->cap_effective)) { if (!cap_issubset(CAP_FULL_SET, new->cap_effective) || new->euid != 0 || new->uid != 0 || issecure(SECURE_NOROOT)) { ret = audit_log_bprm_fcaps(bprm, new, old); if (ret < 0) return ret; } } new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); return 0; } /** * cap_bprm_secureexec - Determine whether a secure execution is required * @bprm: The execution parameters * * Determine whether a secure execution is required, return 1 if it is, and 0 * if it is not. * * The credentials have been committed by this point, and so are no longer * available through @bprm->cred. */ int cap_bprm_secureexec(struct linux_binprm *bprm) { const struct cred *cred = current_cred(); if (cred->uid != 0) { if (bprm->cap_effective) return 1; if (!cap_isclear(cred->cap_permitted)) return 1; } return (cred->euid != cred->uid || cred->egid != cred->gid); } /** * cap_inode_setxattr - Determine whether an xattr may be altered * @dentry: The inode/dentry being altered * @name: The name of the xattr to be changed * @value: The value that the xattr will be changed to * @size: The size of value * @flags: The replacement flag * * Determine whether an xattr may be altered or set on an inode, returning 0 if * permission is granted, -ve if denied. * * This is used to make sure security xattrs don't get updated or set by those * who aren't privileged to do so. */ int cap_inode_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { if (!strcmp(name, XATTR_NAME_CAPS)) { if (!capable(CAP_SETFCAP)) return -EPERM; return 0; } if (!strncmp(name, XATTR_SECURITY_PREFIX, sizeof(XATTR_SECURITY_PREFIX) - 1) && !capable(CAP_SYS_ADMIN)) return -EPERM; return 0; } /** * cap_inode_removexattr - Determine whether an xattr may be removed * @dentry: The inode/dentry being altered * @name: The name of the xattr to be changed * * Determine whether an xattr may be removed from an inode, returning 0 if * permission is granted, -ve if denied. * * This is used to make sure security xattrs don't get removed by those who * aren't privileged to remove them. */ int cap_inode_removexattr(struct dentry *dentry, const char *name) { if (!strcmp(name, XATTR_NAME_CAPS)) { if (!capable(CAP_SETFCAP)) return -EPERM; return 0; } if (!strncmp(name, XATTR_SECURITY_PREFIX, sizeof(XATTR_SECURITY_PREFIX) - 1) && !capable(CAP_SYS_ADMIN)) return -EPERM; return 0; } /* * cap_emulate_setxuid() fixes the effective / permitted capabilities of * a process after a call to setuid, setreuid, or setresuid. * * 1) When set*uiding _from_ one of {r,e,s}uid == 0 _to_ all of * {r,e,s}uid != 0, the permitted and effective capabilities are * cleared. * * 2) When set*uiding _from_ euid == 0 _to_ euid != 0, the effective * capabilities of the process are cleared. * * 3) When set*uiding _from_ euid != 0 _to_ euid == 0, the effective * capabilities are set to the permitted capabilities. * * fsuid is handled elsewhere. fsuid == 0 and {r,e,s}uid!= 0 should * never happen. * * -astor * * cevans - New behaviour, Oct '99 * A process may, via prctl(), elect to keep its capabilities when it * calls setuid() and switches away from uid==0. Both permitted and * effective sets will be retained. * Without this change, it was impossible for a daemon to drop only some * of its privilege. The call to setuid(!=0) would drop all privileges! * Keeping uid 0 is not an option because uid 0 owns too many vital * files.. * Thanks to Olaf Kirch and Peter Benie for spotting this. */ static inline void cap_emulate_setxuid(struct cred *new, const struct cred *old) { if ((old->uid == 0 || old->euid == 0 || old->suid == 0) && (new->uid != 0 && new->euid != 0 && new->suid != 0) && !issecure(SECURE_KEEP_CAPS)) { cap_clear(new->cap_permitted); cap_clear(new->cap_effective); } if (old->euid == 0 && new->euid != 0) cap_clear(new->cap_effective); if (old->euid != 0 && new->euid == 0) new->cap_effective = new->cap_permitted; } /** * cap_task_fix_setuid - Fix up the results of setuid() call * @new: The proposed credentials * @old: The current task's current credentials * @flags: Indications of what has changed * * Fix up the results of setuid() call before the credential changes are * actually applied, returning 0 to grant the changes, -ve to deny them. */ int cap_task_fix_setuid(struct cred *new, const struct cred *old, int flags) { switch (flags) { case LSM_SETID_RE: case LSM_SETID_ID: case LSM_SETID_RES: /* juggle the capabilities to follow [RES]UID changes unless * otherwise suppressed */ if (!issecure(SECURE_NO_SETUID_FIXUP)) cap_emulate_setxuid(new, old); break; case LSM_SETID_FS: /* juggle the capabilties to follow FSUID changes, unless * otherwise suppressed * * FIXME - is fsuser used for all CAP_FS_MASK capabilities? * if not, we might be a bit too harsh here. */ if (!issecure(SECURE_NO_SETUID_FIXUP)) { if (old->fsuid == 0 && new->fsuid != 0) new->cap_effective = cap_drop_fs_set(new->cap_effective); if (old->fsuid != 0 && new->fsuid == 0) new->cap_effective = cap_raise_fs_set(new->cap_effective, new->cap_permitted); } break; default: return -EINVAL; } return 0; } /* * Rationale: code calling task_setscheduler, task_setioprio, and * task_setnice, assumes that * . if capable(cap_sys_nice), then those actions should be allowed * . if not capable(cap_sys_nice), but acting on your own processes, * then those actions should be allowed * This is insufficient now since you can call code without suid, but * yet with increased caps. * So we check for increased caps on the target process. */ static int cap_safe_nice(struct task_struct *p) { int is_subset; rcu_read_lock(); is_subset = cap_issubset(__task_cred(p)->cap_permitted, current_cred()->cap_permitted); rcu_read_unlock(); if (!is_subset && !capable(CAP_SYS_NICE)) return -EPERM; return 0; } /** * cap_task_setscheduler - Detemine if scheduler policy change is permitted * @p: The task to affect * * Detemine if the requested scheduler policy change is permitted for the * specified task, returning 0 if permission is granted, -ve if denied. */ int cap_task_setscheduler(struct task_struct *p) { return cap_safe_nice(p); } /** * cap_task_ioprio - Detemine if I/O priority change is permitted * @p: The task to affect * @ioprio: The I/O priority to set * * Detemine if the requested I/O priority change is permitted for the specified * task, returning 0 if permission is granted, -ve if denied. */ int cap_task_setioprio(struct task_struct *p, int ioprio) { return cap_safe_nice(p); } /** * cap_task_ioprio - Detemine if task priority change is permitted * @p: The task to affect * @nice: The nice value to set * * Detemine if the requested task priority change is permitted for the * specified task, returning 0 if permission is granted, -ve if denied. */ int cap_task_setnice(struct task_struct *p, int nice) { return cap_safe_nice(p); } /* * 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) { if (!capable(CAP_SETPCAP)) return -EPERM; if (!cap_valid(cap)) return -EINVAL; cap_lower(new->cap_bset, cap); return 0; } /** * 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) { struct cred *new; long error = 0; new = prepare_creds(); if (!new) return -ENOMEM; switch (option) { case PR_CAPBSET_READ: error = -EINVAL; if (!cap_valid(arg2)) goto error; error = !!cap_raised(new->cap_bset, arg2); goto no_change; case PR_CAPBSET_DROP: error = cap_prctl_drop(new, arg2); if (error < 0) goto error; goto changed; /* * The next four prctl's remain to assist with transitioning a * system from legacy UID=0 based privilege (when filesystem * capabilities are not in use) to a system using filesystem * capabilities only - as the POSIX.1e draft intended. * * Note: * * PR_SET_SECUREBITS = * issecure_mask(SECURE_KEEP_CAPS_LOCKED) * | issecure_mask(SECURE_NOROOT) * | issecure_mask(SECURE_NOROOT_LOCKED) * | issecure_mask(SECURE_NO_SETUID_FIXUP) * | issecure_mask(SECURE_NO_SETUID_FIXUP_LOCKED) * * will ensure that the current process and all of its * children will be locked into a pure * capability-based-privilege environment. */ case PR_SET_SECUREBITS: error = -EPERM; if ((((new->securebits & SECURE_ALL_LOCKS) >> 1) & (new->securebits ^ arg2)) /*[1]*/ || ((new->securebits & SECURE_ALL_LOCKS & ~arg2)) /*[2]*/ || (arg2 & ~(SECURE_ALL_LOCKS | SECURE_ALL_BITS)) /*[3]*/ || (cap_capable(current, current_cred(), current_cred()->user->user_ns, CAP_SETPCAP, SECURITY_CAP_AUDIT) != 0) /*[4]*/ /* * [1] no changing of bits that are locked * [2] no unlocking of locks * [3] no setting of unsupported bits * [4] doing anything requires privilege (go read about * the "sendmail capabilities bug") */ ) /* cannot change a locked bit */ goto error; new->securebits = arg2; goto changed; case PR_GET_SECUREBITS: error = new->securebits; goto no_change; case PR_GET_KEEPCAPS: if (issecure(SECURE_KEEP_CAPS)) error = 1; goto no_change; case PR_SET_KEEPCAPS: error = -EINVAL; if (arg2 > 1) /* Note, we rely on arg2 being unsigned here */ goto error; error = -EPERM; if (issecure(SECURE_KEEP_CAPS_LOCKED)) goto error; if (arg2) new->securebits |= issecure_mask(SECURE_KEEP_CAPS); else new->securebits &= ~issecure_mask(SECURE_KEEP_CAPS); goto changed; default: /* No functionality available - continue with default */ error = -ENOSYS; goto error; } /* Functionality provided */ changed: return commit_creds(new); no_change: error: abort_creds(new); return error; } /** * 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; if (cap_capable(current, current_cred(), &init_user_ns, CAP_SYS_ADMIN, SECURITY_CAP_NOAUDIT) == 0) cap_sys_admin = 1; return __vm_enough_memory(mm, pages, cap_sys_admin); } /* * cap_file_mmap - check if able to map given addr * @file: unused * @reqprot: unused * @prot: unused * @flags: unused * @addr: address attempting to be mapped * @addr_only: unused * * If the process is attempting to map memory below dac_mmap_min_addr they need * CAP_SYS_RAWIO. The other parameters to this function are unused by the * capability security module. Returns 0 if this mapping should be allowed * -EPERM if not. */ int cap_file_mmap(struct file *file, unsigned long reqprot, unsigned long prot, unsigned long flags, unsigned long addr, unsigned long addr_only) { int ret = 0; if (addr < dac_mmap_min_addr) { ret = cap_capable(current, current_cred(), &init_user_ns, CAP_SYS_RAWIO, SECURITY_CAP_AUDIT); /* set PF_SUPERPRIV if it turns out we allow the low mmap */ if (ret == 0) current->flags |= PF_SUPERPRIV; } return ret; }