diff options
Diffstat (limited to 'kernel/sys.c')
| -rw-r--r-- | kernel/sys.c | 2408 |
1 files changed, 2408 insertions, 0 deletions
diff --git a/kernel/sys.c b/kernel/sys.c new file mode 100644 index 000000000..a4e372b79 --- /dev/null +++ b/kernel/sys.c @@ -0,0 +1,2408 @@ +/* + * linux/kernel/sys.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + */ + +#include <linux/export.h> +#include <linux/mm.h> +#include <linux/utsname.h> +#include <linux/mman.h> +#include <linux/reboot.h> +#include <linux/prctl.h> +#include <linux/highuid.h> +#include <linux/fs.h> +#include <linux/kmod.h> +#include <linux/perf_event.h> +#include <linux/resource.h> +#include <linux/kernel.h> +#include <linux/workqueue.h> +#include <linux/capability.h> +#include <linux/device.h> +#include <linux/key.h> +#include <linux/times.h> +#include <linux/posix-timers.h> +#include <linux/security.h> +#include <linux/dcookies.h> +#include <linux/suspend.h> +#include <linux/tty.h> +#include <linux/signal.h> +#include <linux/cn_proc.h> +#include <linux/getcpu.h> +#include <linux/task_io_accounting_ops.h> +#include <linux/seccomp.h> +#include <linux/cpu.h> +#include <linux/personality.h> +#include <linux/ptrace.h> +#include <linux/fs_struct.h> +#include <linux/file.h> +#include <linux/mount.h> +#include <linux/gfp.h> +#include <linux/syscore_ops.h> +#include <linux/version.h> +#include <linux/ctype.h> + +#include <linux/compat.h> +#include <linux/syscalls.h> +#include <linux/kprobes.h> +#include <linux/user_namespace.h> +#include <linux/binfmts.h> + +#include <linux/sched.h> +#include <linux/rcupdate.h> +#include <linux/uidgid.h> +#include <linux/cred.h> + +#include <linux/kmsg_dump.h> +/* Move somewhere else to avoid recompiling? */ +#include <generated/utsrelease.h> + +#include <asm/uaccess.h> +#include <asm/io.h> +#include <asm/unistd.h> + +#ifndef SET_UNALIGN_CTL +# define SET_UNALIGN_CTL(a, b) (-EINVAL) +#endif +#ifndef GET_UNALIGN_CTL +# define GET_UNALIGN_CTL(a, b) (-EINVAL) +#endif +#ifndef SET_FPEMU_CTL +# define SET_FPEMU_CTL(a, b) (-EINVAL) +#endif +#ifndef GET_FPEMU_CTL +# define GET_FPEMU_CTL(a, b) (-EINVAL) +#endif +#ifndef SET_FPEXC_CTL +# define SET_FPEXC_CTL(a, b) (-EINVAL) +#endif +#ifndef GET_FPEXC_CTL +# define GET_FPEXC_CTL(a, b) (-EINVAL) +#endif +#ifndef GET_ENDIAN +# define GET_ENDIAN(a, b) (-EINVAL) +#endif +#ifndef SET_ENDIAN +# define SET_ENDIAN(a, b) (-EINVAL) +#endif +#ifndef GET_TSC_CTL +# define GET_TSC_CTL(a) (-EINVAL) +#endif +#ifndef SET_TSC_CTL +# define SET_TSC_CTL(a) (-EINVAL) +#endif +#ifndef MPX_ENABLE_MANAGEMENT +# define MPX_ENABLE_MANAGEMENT(a) (-EINVAL) +#endif +#ifndef MPX_DISABLE_MANAGEMENT +# define MPX_DISABLE_MANAGEMENT(a) (-EINVAL) +#endif +#ifndef GET_FP_MODE +# define GET_FP_MODE(a) (-EINVAL) +#endif +#ifndef SET_FP_MODE +# define SET_FP_MODE(a,b) (-EINVAL) +#endif + +/* + * this is where the system-wide overflow UID and GID are defined, for + * architectures that now have 32-bit UID/GID but didn't in the past + */ + +int overflowuid = DEFAULT_OVERFLOWUID; +int overflowgid = DEFAULT_OVERFLOWGID; + +EXPORT_SYMBOL(overflowuid); +EXPORT_SYMBOL(overflowgid); + +/* + * the same as above, but for filesystems which can only store a 16-bit + * UID and GID. as such, this is needed on all architectures + */ + +int fs_overflowuid = DEFAULT_FS_OVERFLOWUID; +int fs_overflowgid = DEFAULT_FS_OVERFLOWUID; + +EXPORT_SYMBOL(fs_overflowuid); +EXPORT_SYMBOL(fs_overflowgid); + +/* + * Returns true if current's euid is same as p's uid or euid, + * or has CAP_SYS_NICE to p's user_ns. + * + * Called with rcu_read_lock, creds are safe + */ +static bool set_one_prio_perm(struct task_struct *p) +{ + const struct cred *cred = current_cred(), *pcred = __task_cred(p); + + if (uid_eq(pcred->uid, cred->euid) || + uid_eq(pcred->euid, cred->euid)) + return true; + if (ns_capable(pcred->user_ns, CAP_SYS_NICE)) + return true; + return false; +} + +/* + * set the priority of a task + * - the caller must hold the RCU read lock + */ +static int set_one_prio(struct task_struct *p, int niceval, int error) +{ + int no_nice; + + if (!set_one_prio_perm(p)) { + error = -EPERM; + goto out; + } + if (niceval < task_nice(p) && !can_nice(p, niceval)) { + error = -EACCES; + goto out; + } + no_nice = security_task_setnice(p, niceval); + if (no_nice) { + error = no_nice; + goto out; + } + if (error == -ESRCH) + error = 0; + set_user_nice(p, niceval); +out: + return error; +} + +SYSCALL_DEFINE3(setpriority, int, which, int, who, int, niceval) +{ + struct task_struct *g, *p; + struct user_struct *user; + const struct cred *cred = current_cred(); + int error = -EINVAL; + struct pid *pgrp; + kuid_t uid; + + if (which > PRIO_USER || which < PRIO_PROCESS) + goto out; + + /* normalize: avoid signed division (rounding problems) */ + error = -ESRCH; + if (niceval < MIN_NICE) + niceval = MIN_NICE; + if (niceval > MAX_NICE) + niceval = MAX_NICE; + + rcu_read_lock(); + read_lock(&tasklist_lock); + switch (which) { + case PRIO_PROCESS: + if (who) + p = find_task_by_vpid(who); + else + p = current; + if (p) + error = set_one_prio(p, niceval, error); + break; + case PRIO_PGRP: + if (who) + pgrp = find_vpid(who); + else + pgrp = task_pgrp(current); + do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { + error = set_one_prio(p, niceval, error); + } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); + break; + case PRIO_USER: + uid = make_kuid(cred->user_ns, who); + user = cred->user; + if (!who) + uid = cred->uid; + else if (!uid_eq(uid, cred->uid)) { + user = find_user(uid); + if (!user) + goto out_unlock; /* No processes for this user */ + } + do_each_thread(g, p) { + if (uid_eq(task_uid(p), uid)) + error = set_one_prio(p, niceval, error); + } while_each_thread(g, p); + if (!uid_eq(uid, cred->uid)) + free_uid(user); /* For find_user() */ + break; + } +out_unlock: + read_unlock(&tasklist_lock); + rcu_read_unlock(); +out: + return error; +} + +/* + * Ugh. To avoid negative return values, "getpriority()" will + * not return the normal nice-value, but a negated value that + * has been offset by 20 (ie it returns 40..1 instead of -20..19) + * to stay compatible. + */ +SYSCALL_DEFINE2(getpriority, int, which, int, who) +{ + struct task_struct *g, *p; + struct user_struct *user; + const struct cred *cred = current_cred(); + long niceval, retval = -ESRCH; + struct pid *pgrp; + kuid_t uid; + + if (which > PRIO_USER || which < PRIO_PROCESS) + return -EINVAL; + + rcu_read_lock(); + read_lock(&tasklist_lock); + switch (which) { + case PRIO_PROCESS: + if (who) + p = find_task_by_vpid(who); + else + p = current; + if (p) { + niceval = nice_to_rlimit(task_nice(p)); + if (niceval > retval) + retval = niceval; + } + break; + case PRIO_PGRP: + if (who) + pgrp = find_vpid(who); + else + pgrp = task_pgrp(current); + do_each_pid_thread(pgrp, PIDTYPE_PGID, p) { + niceval = nice_to_rlimit(task_nice(p)); + if (niceval > retval) + retval = niceval; + } while_each_pid_thread(pgrp, PIDTYPE_PGID, p); + break; + case PRIO_USER: + uid = make_kuid(cred->user_ns, who); + user = cred->user; + if (!who) + uid = cred->uid; + else if (!uid_eq(uid, cred->uid)) { + user = find_user(uid); + if (!user) + goto out_unlock; /* No processes for this user */ + } + do_each_thread(g, p) { + if (uid_eq(task_uid(p), uid)) { + niceval = nice_to_rlimit(task_nice(p)); + if (niceval > retval) + retval = niceval; + } + } while_each_thread(g, p); + if (!uid_eq(uid, cred->uid)) + free_uid(user); /* for find_user() */ + break; + } +out_unlock: + read_unlock(&tasklist_lock); + rcu_read_unlock(); + + return retval; +} + +/* + * Unprivileged users may change the real gid to the effective gid + * or vice versa. (BSD-style) + * + * If you set the real gid at all, or set the effective gid to a value not + * equal to the real gid, then the saved gid is set to the new effective gid. + * + * This makes it possible for a setgid program to completely drop its + * privileges, which is often a useful assertion to make when you are doing + * a security audit over a program. + * + * The general idea is that a program which uses just setregid() will be + * 100% compatible with BSD. A program which uses just setgid() will be + * 100% compatible with POSIX with saved IDs. + * + * SMP: There are not races, the GIDs are checked only by filesystem + * operations (as far as semantic preservation is concerned). + */ +#ifdef CONFIG_MULTIUSER +SYSCALL_DEFINE2(setregid, gid_t, rgid, gid_t, egid) +{ + struct user_namespace *ns = current_user_ns(); + const struct cred *old; + struct cred *new; + int retval; + kgid_t krgid, kegid; + + krgid = make_kgid(ns, rgid); + kegid = make_kgid(ns, egid); + + if ((rgid != (gid_t) -1) && !gid_valid(krgid)) + return -EINVAL; + if ((egid != (gid_t) -1) && !gid_valid(kegid)) + return -EINVAL; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + old = current_cred(); + + retval = -EPERM; + if (rgid != (gid_t) -1) { + if (gid_eq(old->gid, krgid) || + gid_eq(old->egid, krgid) || + ns_capable(old->user_ns, CAP_SETGID)) + new->gid = krgid; + else + goto error; + } + if (egid != (gid_t) -1) { + if (gid_eq(old->gid, kegid) || + gid_eq(old->egid, kegid) || + gid_eq(old->sgid, kegid) || + ns_capable(old->user_ns, CAP_SETGID)) + new->egid = kegid; + else + goto error; + } + + if (rgid != (gid_t) -1 || + (egid != (gid_t) -1 && !gid_eq(kegid, old->gid))) + new->sgid = new->egid; + new->fsgid = new->egid; + + return commit_creds(new); + +error: + abort_creds(new); + return retval; +} + +/* + * setgid() is implemented like SysV w/ SAVED_IDS + * + * SMP: Same implicit races as above. + */ +SYSCALL_DEFINE1(setgid, gid_t, gid) +{ + struct user_namespace *ns = current_user_ns(); + const struct cred *old; + struct cred *new; + int retval; + kgid_t kgid; + + kgid = make_kgid(ns, gid); + if (!gid_valid(kgid)) + return -EINVAL; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + old = current_cred(); + + retval = -EPERM; + if (ns_capable(old->user_ns, CAP_SETGID)) + new->gid = new->egid = new->sgid = new->fsgid = kgid; + else if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->sgid)) + new->egid = new->fsgid = kgid; + else + goto error; + + return commit_creds(new); + +error: + abort_creds(new); + return retval; +} + +/* + * change the user struct in a credentials set to match the new UID + */ +static int set_user(struct cred *new) +{ + struct user_struct *new_user; + + new_user = alloc_uid(new->uid); + if (!new_user) + return -EAGAIN; + + /* + * We don't fail in case of NPROC limit excess here because too many + * poorly written programs don't check set*uid() return code, assuming + * it never fails if called by root. We may still enforce NPROC limit + * for programs doing set*uid()+execve() by harmlessly deferring the + * failure to the execve() stage. + */ + if (atomic_read(&new_user->processes) >= rlimit(RLIMIT_NPROC) && + new_user != INIT_USER) + current->flags |= PF_NPROC_EXCEEDED; + else + current->flags &= ~PF_NPROC_EXCEEDED; + + free_uid(new->user); + new->user = new_user; + return 0; +} + +/* + * Unprivileged users may change the real uid to the effective uid + * or vice versa. (BSD-style) + * + * If you set the real uid at all, or set the effective uid to a value not + * equal to the real uid, then the saved uid is set to the new effective uid. + * + * This makes it possible for a setuid program to completely drop its + * privileges, which is often a useful assertion to make when you are doing + * a security audit over a program. + * + * The general idea is that a program which uses just setreuid() will be + * 100% compatible with BSD. A program which uses just setuid() will be + * 100% compatible with POSIX with saved IDs. + */ +SYSCALL_DEFINE2(setreuid, uid_t, ruid, uid_t, euid) +{ + struct user_namespace *ns = current_user_ns(); + const struct cred *old; + struct cred *new; + int retval; + kuid_t kruid, keuid; + + kruid = make_kuid(ns, ruid); + keuid = make_kuid(ns, euid); + + if ((ruid != (uid_t) -1) && !uid_valid(kruid)) + return -EINVAL; + if ((euid != (uid_t) -1) && !uid_valid(keuid)) + return -EINVAL; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + old = current_cred(); + + retval = -EPERM; + if (ruid != (uid_t) -1) { + new->uid = kruid; + if (!uid_eq(old->uid, kruid) && + !uid_eq(old->euid, kruid) && + !ns_capable(old->user_ns, CAP_SETUID)) + goto error; + } + + if (euid != (uid_t) -1) { + new->euid = keuid; + if (!uid_eq(old->uid, keuid) && + !uid_eq(old->euid, keuid) && + !uid_eq(old->suid, keuid) && + !ns_capable(old->user_ns, CAP_SETUID)) + goto error; + } + + if (!uid_eq(new->uid, old->uid)) { + retval = set_user(new); + if (retval < 0) + goto error; + } + if (ruid != (uid_t) -1 || + (euid != (uid_t) -1 && !uid_eq(keuid, old->uid))) + new->suid = new->euid; + new->fsuid = new->euid; + + retval = security_task_fix_setuid(new, old, LSM_SETID_RE); + if (retval < 0) + goto error; + + return commit_creds(new); + +error: + abort_creds(new); + return retval; +} + +/* + * setuid() is implemented like SysV with SAVED_IDS + * + * Note that SAVED_ID's is deficient in that a setuid root program + * like sendmail, for example, cannot set its uid to be a normal + * user and then switch back, because if you're root, setuid() sets + * the saved uid too. If you don't like this, blame the bright people + * in the POSIX committee and/or USG. Note that the BSD-style setreuid() + * will allow a root program to temporarily drop privileges and be able to + * regain them by swapping the real and effective uid. + */ +SYSCALL_DEFINE1(setuid, uid_t, uid) +{ + struct user_namespace *ns = current_user_ns(); + const struct cred *old; + struct cred *new; + int retval; + kuid_t kuid; + + kuid = make_kuid(ns, uid); + if (!uid_valid(kuid)) + return -EINVAL; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + old = current_cred(); + + retval = -EPERM; + if (ns_capable(old->user_ns, CAP_SETUID)) { + new->suid = new->uid = kuid; + if (!uid_eq(kuid, old->uid)) { + retval = set_user(new); + if (retval < 0) + goto error; + } + } else if (!uid_eq(kuid, old->uid) && !uid_eq(kuid, new->suid)) { + goto error; + } + + new->fsuid = new->euid = kuid; + + retval = security_task_fix_setuid(new, old, LSM_SETID_ID); + if (retval < 0) + goto error; + + return commit_creds(new); + +error: + abort_creds(new); + return retval; +} + + +/* + * This function implements a generic ability to update ruid, euid, + * and suid. This allows you to implement the 4.4 compatible seteuid(). + */ +SYSCALL_DEFINE3(setresuid, uid_t, ruid, uid_t, euid, uid_t, suid) +{ + struct user_namespace *ns = current_user_ns(); + const struct cred *old; + struct cred *new; + int retval; + kuid_t kruid, keuid, ksuid; + + kruid = make_kuid(ns, ruid); + keuid = make_kuid(ns, euid); + ksuid = make_kuid(ns, suid); + + if ((ruid != (uid_t) -1) && !uid_valid(kruid)) + return -EINVAL; + + if ((euid != (uid_t) -1) && !uid_valid(keuid)) + return -EINVAL; + + if ((suid != (uid_t) -1) && !uid_valid(ksuid)) + return -EINVAL; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + + old = current_cred(); + + retval = -EPERM; + if (!ns_capable(old->user_ns, CAP_SETUID)) { + if (ruid != (uid_t) -1 && !uid_eq(kruid, old->uid) && + !uid_eq(kruid, old->euid) && !uid_eq(kruid, old->suid)) + goto error; + if (euid != (uid_t) -1 && !uid_eq(keuid, old->uid) && + !uid_eq(keuid, old->euid) && !uid_eq(keuid, old->suid)) + goto error; + if (suid != (uid_t) -1 && !uid_eq(ksuid, old->uid) && + !uid_eq(ksuid, old->euid) && !uid_eq(ksuid, old->suid)) + goto error; + } + + if (ruid != (uid_t) -1) { + new->uid = kruid; + if (!uid_eq(kruid, old->uid)) { + retval = set_user(new); + if (retval < 0) + goto error; + } + } + if (euid != (uid_t) -1) + new->euid = keuid; + if (suid != (uid_t) -1) + new->suid = ksuid; + new->fsuid = new->euid; + + retval = security_task_fix_setuid(new, old, LSM_SETID_RES); + if (retval < 0) + goto error; + + return commit_creds(new); + +error: + abort_creds(new); + return retval; +} + +SYSCALL_DEFINE3(getresuid, uid_t __user *, ruidp, uid_t __user *, euidp, uid_t __user *, suidp) +{ + const struct cred *cred = current_cred(); + int retval; + uid_t ruid, euid, suid; + + ruid = from_kuid_munged(cred->user_ns, cred->uid); + euid = from_kuid_munged(cred->user_ns, cred->euid); + suid = from_kuid_munged(cred->user_ns, cred->suid); + + retval = put_user(ruid, ruidp); + if (!retval) { + retval = put_user(euid, euidp); + if (!retval) + return put_user(suid, suidp); + } + return retval; +} + +/* + * Same as above, but for rgid, egid, sgid. + */ +SYSCALL_DEFINE3(setresgid, gid_t, rgid, gid_t, egid, gid_t, sgid) +{ + struct user_namespace *ns = current_user_ns(); + const struct cred *old; + struct cred *new; + int retval; + kgid_t krgid, kegid, ksgid; + + krgid = make_kgid(ns, rgid); + kegid = make_kgid(ns, egid); + ksgid = make_kgid(ns, sgid); + + if ((rgid != (gid_t) -1) && !gid_valid(krgid)) + return -EINVAL; + if ((egid != (gid_t) -1) && !gid_valid(kegid)) + return -EINVAL; + if ((sgid != (gid_t) -1) && !gid_valid(ksgid)) + return -EINVAL; + + new = prepare_creds(); + if (!new) + return -ENOMEM; + old = current_cred(); + + retval = -EPERM; + if (!ns_capable(old->user_ns, CAP_SETGID)) { + if (rgid != (gid_t) -1 && !gid_eq(krgid, old->gid) && + !gid_eq(krgid, old->egid) && !gid_eq(krgid, old->sgid)) + goto error; + if (egid != (gid_t) -1 && !gid_eq(kegid, old->gid) && + !gid_eq(kegid, old->egid) && !gid_eq(kegid, old->sgid)) + goto error; + if (sgid != (gid_t) -1 && !gid_eq(ksgid, old->gid) && + !gid_eq(ksgid, old->egid) && !gid_eq(ksgid, old->sgid)) + goto error; + } + + if (rgid != (gid_t) -1) + new->gid = krgid; + if (egid != (gid_t) -1) + new->egid = kegid; + if (sgid != (gid_t) -1) + new->sgid = ksgid; + new->fsgid = new->egid; + + return commit_creds(new); + +error: + abort_creds(new); + return retval; +} + +SYSCALL_DEFINE3(getresgid, gid_t __user *, rgidp, gid_t __user *, egidp, gid_t __user *, sgidp) +{ + const struct cred *cred = current_cred(); + int retval; + gid_t rgid, egid, sgid; + + rgid = from_kgid_munged(cred->user_ns, cred->gid); + egid = from_kgid_munged(cred->user_ns, cred->egid); + sgid = from_kgid_munged(cred->user_ns, cred->sgid); + + retval = put_user(rgid, rgidp); + if (!retval) { + retval = put_user(egid, egidp); + if (!retval) + retval = put_user(sgid, sgidp); + } + + return retval; +} + + +/* + * "setfsuid()" sets the fsuid - the uid used for filesystem checks. This + * is used for "access()" and for the NFS daemon (letting nfsd stay at + * whatever uid it wants to). It normally shadows "euid", except when + * explicitly set by setfsuid() or for access.. + */ +SYSCALL_DEFINE1(setfsuid, uid_t, uid) +{ + const struct cred *old; + struct cred *new; + uid_t old_fsuid; + kuid_t kuid; + + old = current_cred(); + old_fsuid = from_kuid_munged(old->user_ns, old->fsuid); + + kuid = make_kuid(old->user_ns, uid); + if (!uid_valid(kuid)) + return old_fsuid; + + new = prepare_creds(); + if (!new) + return old_fsuid; + + if (uid_eq(kuid, old->uid) || uid_eq(kuid, old->euid) || + uid_eq(kuid, old->suid) || uid_eq(kuid, old->fsuid) || + ns_capable(old->user_ns, CAP_SETUID)) { + if (!uid_eq(kuid, old->fsuid)) { + new->fsuid = kuid; + if (security_task_fix_setuid(new, old, LSM_SETID_FS) == 0) + goto change_okay; + } + } + + abort_creds(new); + return old_fsuid; + +change_okay: + commit_creds(new); + return old_fsuid; +} + +/* + * Samma på svenska.. + */ +SYSCALL_DEFINE1(setfsgid, gid_t, gid) +{ + const struct cred *old; + struct cred *new; + gid_t old_fsgid; + kgid_t kgid; + + old = current_cred(); + old_fsgid = from_kgid_munged(old->user_ns, old->fsgid); + + kgid = make_kgid(old->user_ns, gid); + if (!gid_valid(kgid)) + return old_fsgid; + + new = prepare_creds(); + if (!new) + return old_fsgid; + + if (gid_eq(kgid, old->gid) || gid_eq(kgid, old->egid) || + gid_eq(kgid, old->sgid) || gid_eq(kgid, old->fsgid) || + ns_capable(old->user_ns, CAP_SETGID)) { + if (!gid_eq(kgid, old->fsgid)) { + new->fsgid = kgid; + goto change_okay; + } + } + + abort_creds(new); + return old_fsgid; + +change_okay: + commit_creds(new); + return old_fsgid; +} +#endif /* CONFIG_MULTIUSER */ + +/** + * sys_getpid - return the thread group id of the current process + * + * Note, despite the name, this returns the tgid not the pid. The tgid and + * the pid are identical unless CLONE_THREAD was specified on clone() in + * which case the tgid is the same in all threads of the same group. + * + * This is SMP safe as current->tgid does not change. + */ +SYSCALL_DEFINE0(getpid) +{ + return task_tgid_vnr(current); +} + +/* Thread ID - the internal kernel "pid" */ +SYSCALL_DEFINE0(gettid) +{ + return task_pid_vnr(current); +} + +/* + * Accessing ->real_parent is not SMP-safe, it could + * change from under us. However, we can use a stale + * value of ->real_parent under rcu_read_lock(), see + * release_task()->call_rcu(delayed_put_task_struct). + */ +SYSCALL_DEFINE0(getppid) +{ + int pid; + + rcu_read_lock(); + pid = task_tgid_vnr(rcu_dereference(current->real_parent)); + rcu_read_unlock(); + + return pid; +} + +SYSCALL_DEFINE0(getuid) +{ + /* Only we change this so SMP safe */ + return from_kuid_munged(current_user_ns(), current_uid()); +} + +SYSCALL_DEFINE0(geteuid) +{ + /* Only we change this so SMP safe */ + return from_kuid_munged(current_user_ns(), current_euid()); +} + +SYSCALL_DEFINE0(getgid) +{ + /* Only we change this so SMP safe */ + return from_kgid_munged(current_user_ns(), current_gid()); +} + +SYSCALL_DEFINE0(getegid) +{ + /* Only we change this so SMP safe */ + return from_kgid_munged(current_user_ns(), current_egid()); +} + +void do_sys_times(struct tms *tms) +{ + cputime_t tgutime, tgstime, cutime, cstime; + + thread_group_cputime_adjusted(current, &tgutime, &tgstime); + cutime = current->signal->cutime; + cstime = current->signal->cstime; + tms->tms_utime = cputime_to_clock_t(tgutime); + tms->tms_stime = cputime_to_clock_t(tgstime); + tms->tms_cutime = cputime_to_clock_t(cutime); + tms->tms_cstime = cputime_to_clock_t(cstime); +} + +SYSCALL_DEFINE1(times, struct tms __user *, tbuf) +{ + if (tbuf) { + struct tms tmp; + + do_sys_times(&tmp); + if (copy_to_user(tbuf, &tmp, sizeof(struct tms))) + return -EFAULT; + } + force_successful_syscall_return(); + return (long) jiffies_64_to_clock_t(get_jiffies_64()); +} + +/* + * This needs some heavy checking ... + * I just haven't the stomach for it. I also don't fully + * understand sessions/pgrp etc. Let somebody who does explain it. + * + * OK, I think I have the protection semantics right.... this is really + * only important on a multi-user system anyway, to make sure one user + * can't send a signal to a process owned by another. -TYT, 12/12/91 + * + * !PF_FORKNOEXEC check to conform completely to POSIX. + */ +SYSCALL_DEFINE2(setpgid, pid_t, pid, pid_t, pgid) +{ + struct task_struct *p; + struct task_struct *group_leader = current->group_leader; + struct pid *pgrp; + int err; + + if (!pid) + pid = task_pid_vnr(group_leader); + if (!pgid) + pgid = pid; + if (pgid < 0) + return -EINVAL; + rcu_read_lock(); + + /* From this point forward we keep holding onto the tasklist lock + * so that our parent does not change from under us. -DaveM + */ + write_lock_irq(&tasklist_lock); + + err = -ESRCH; + p = find_task_by_vpid(pid); + if (!p) + goto out; + + err = -EINVAL; + if (!thread_group_leader(p)) + goto out; + + if (same_thread_group(p->real_parent, group_leader)) { + err = -EPERM; + if (task_session(p) != task_session(group_leader)) + goto out; + err = -EACCES; + if (!(p->flags & PF_FORKNOEXEC)) + goto out; + } else { + err = -ESRCH; + if (p != group_leader) + goto out; + } + + err = -EPERM; + if (p->signal->leader) + goto out; + + pgrp = task_pid(p); + if (pgid != pid) { + struct task_struct *g; + + pgrp = find_vpid(pgid); + g = pid_task(pgrp, PIDTYPE_PGID); + if (!g || task_session(g) != task_session(group_leader)) + goto out; + } + + err = security_task_setpgid(p, pgid); + if (err) + goto out; + + if (task_pgrp(p) != pgrp) + change_pid(p, PIDTYPE_PGID, pgrp); + + err = 0; +out: + /* All paths lead to here, thus we are safe. -DaveM */ + write_unlock_irq(&tasklist_lock); + rcu_read_unlock(); + return err; +} + +SYSCALL_DEFINE1(getpgid, pid_t, pid) +{ + struct task_struct *p; + struct pid *grp; + int retval; + + rcu_read_lock(); + if (!pid) + grp = task_pgrp(current); + else { + retval = -ESRCH; + p = find_task_by_vpid(pid); + if (!p) + goto out; + grp = task_pgrp(p); + if (!grp) + goto out; + + retval = security_task_getpgid(p); + if (retval) + goto out; + } + retval = pid_vnr(grp); +out: + rcu_read_unlock(); + return retval; +} + +#ifdef __ARCH_WANT_SYS_GETPGRP + +SYSCALL_DEFINE0(getpgrp) +{ + return sys_getpgid(0); +} + +#endif + +SYSCALL_DEFINE1(getsid, pid_t, pid) +{ + struct task_struct *p; + struct pid *sid; + int retval; + + rcu_read_lock(); + if (!pid) + sid = task_session(current); + else { + retval = -ESRCH; + p = find_task_by_vpid(pid); + if (!p) + goto out; + sid = task_session(p); + if (!sid) + goto out; + + retval = security_task_getsid(p); + if (retval) + goto out; + } + retval = pid_vnr(sid); +out: + rcu_read_unlock(); + return retval; +} + +static void set_special_pids(struct pid *pid) +{ + struct task_struct *curr = current->group_leader; + + if (task_session(curr) != pid) + change_pid(curr, PIDTYPE_SID, pid); + + if (task_pgrp(curr) != pid) + change_pid(curr, PIDTYPE_PGID, pid); +} + +SYSCALL_DEFINE0(setsid) +{ + struct task_struct *group_leader = current->group_leader; + struct pid *sid = task_pid(group_leader); + pid_t session = pid_vnr(sid); + int err = -EPERM; + + write_lock_irq(&tasklist_lock); + /* Fail if I am already a session leader */ + if (group_leader->signal->leader) + goto out; + + /* Fail if a process group id already exists that equals the + * proposed session id. + */ + if (pid_task(sid, PIDTYPE_PGID)) + goto out; + + group_leader->signal->leader = 1; + set_special_pids(sid); + + proc_clear_tty(group_leader); + + err = session; +out: + write_unlock_irq(&tasklist_lock); + if (err > 0) { + proc_sid_connector(group_leader); + sched_autogroup_create_attach(group_leader); + } + return err; +} + +DECLARE_RWSEM(uts_sem); + +#ifdef COMPAT_UTS_MACHINE +#define override_architecture(name) \ + (personality(current->personality) == PER_LINUX32 && \ + copy_to_user(name->machine, COMPAT_UTS_MACHINE, \ + sizeof(COMPAT_UTS_MACHINE))) +#else +#define override_architecture(name) 0 +#endif + +/* + * Work around broken programs that cannot handle "Linux 3.0". + * Instead we map 3.x to 2.6.40+x, so e.g. 3.0 would be 2.6.40 + * And we map 4.x to 2.6.60+x, so 4.0 would be 2.6.60. + */ +static int override_release(char __user *release, size_t len) +{ + int ret = 0; + + if (current->personality & UNAME26) { + const char *rest = UTS_RELEASE; + char buf[65] = { 0 }; + int ndots = 0; + unsigned v; + size_t copy; + + while (*rest) { + if (*rest == '.' && ++ndots >= 3) + break; + if (!isdigit(*rest) && *rest != '.') + break; + rest++; + } + v = ((LINUX_VERSION_CODE >> 8) & 0xff) + 60; + copy = clamp_t(size_t, len, 1, sizeof(buf)); + copy = scnprintf(buf, copy, "2.6.%u%s", v, rest); + ret = copy_to_user(release, buf, copy + 1); + } + return ret; +} + +SYSCALL_DEFINE1(newuname, struct new_utsname __user *, name) +{ + int errno = 0; + + down_read(&uts_sem); + if (copy_to_user(name, utsname(), sizeof *name)) + errno = -EFAULT; + up_read(&uts_sem); + + if (!errno && override_release(name->release, sizeof(name->release))) + errno = -EFAULT; + if (!errno && override_architecture(name)) + errno = -EFAULT; + return errno; +} + +#ifdef __ARCH_WANT_SYS_OLD_UNAME +/* + * Old cruft + */ +SYSCALL_DEFINE1(uname, struct old_utsname __user *, name) +{ + int error = 0; + + if (!name) + return -EFAULT; + + down_read(&uts_sem); + if (copy_to_user(name, utsname(), sizeof(*name))) + error = -EFAULT; + up_read(&uts_sem); + + if (!error && override_release(name->release, sizeof(name->release))) + error = -EFAULT; + if (!error && override_architecture(name)) + error = -EFAULT; + return error; +} + +SYSCALL_DEFINE1(olduname, struct oldold_utsname __user *, name) +{ + int error; + + if (!name) + return -EFAULT; + if (!access_ok(VERIFY_WRITE, name, sizeof(struct oldold_utsname))) + return -EFAULT; + + down_read(&uts_sem); + error = __copy_to_user(&name->sysname, &utsname()->sysname, + __OLD_UTS_LEN); + error |= __put_user(0, name->sysname + __OLD_UTS_LEN); + error |= __copy_to_user(&name->nodename, &utsname()->nodename, + __OLD_UTS_LEN); + error |= __put_user(0, name->nodename + __OLD_UTS_LEN); + error |= __copy_to_user(&name->release, &utsname()->release, + __OLD_UTS_LEN); + error |= __put_user(0, name->release + __OLD_UTS_LEN); + error |= __copy_to_user(&name->version, &utsname()->version, + __OLD_UTS_LEN); + error |= __put_user(0, name->version + __OLD_UTS_LEN); + error |= __copy_to_user(&name->machine, &utsname()->machine, + __OLD_UTS_LEN); + error |= __put_user(0, name->machine + __OLD_UTS_LEN); + up_read(&uts_sem); + + if (!error && override_architecture(name)) + error = -EFAULT; + if (!error && override_release(name->release, sizeof(name->release))) + error = -EFAULT; + return error ? -EFAULT : 0; +} +#endif + +SYSCALL_DEFINE2(sethostname, char __user *, name, int, len) +{ + int errno; + char tmp[__NEW_UTS_LEN]; + + if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN)) + return -EPERM; + + if (len < 0 || len > __NEW_UTS_LEN) + return -EINVAL; + down_write(&uts_sem); + errno = -EFAULT; + if (!copy_from_user(tmp, name, len)) { + struct new_utsname *u = utsname(); + + memcpy(u->nodename, tmp, len); + memset(u->nodename + len, 0, sizeof(u->nodename) - len); + errno = 0; + uts_proc_notify(UTS_PROC_HOSTNAME); + } + up_write(&uts_sem); + return errno; +} + +#ifdef __ARCH_WANT_SYS_GETHOSTNAME + +SYSCALL_DEFINE2(gethostname, char __user *, name, int, len) +{ + int i, errno; + struct new_utsname *u; + + if (len < 0) + return -EINVAL; + down_read(&uts_sem); + u = utsname(); + i = 1 + strlen(u->nodename); + if (i > len) + i = len; + errno = 0; + if (copy_to_user(name, u->nodename, i)) + errno = -EFAULT; + up_read(&uts_sem); + return errno; +} + +#endif + +/* + * Only setdomainname; getdomainname can be implemented by calling + * uname() + */ +SYSCALL_DEFINE2(setdomainname, char __user *, name, int, len) +{ + int errno; + char tmp[__NEW_UTS_LEN]; + + if (!ns_capable(current->nsproxy->uts_ns->user_ns, CAP_SYS_ADMIN)) + return -EPERM; + if (len < 0 || len > __NEW_UTS_LEN) + return -EINVAL; + + down_write(&uts_sem); + errno = -EFAULT; + if (!copy_from_user(tmp, name, len)) { + struct new_utsname *u = utsname(); + + memcpy(u->domainname, tmp, len); + memset(u->domainname + len, 0, sizeof(u->domainname) - len); + errno = 0; + uts_proc_notify(UTS_PROC_DOMAINNAME); + } + up_write(&uts_sem); + return errno; +} + +SYSCALL_DEFINE2(getrlimit, unsigned int, resource, struct rlimit __user *, rlim) +{ + struct rlimit value; + int ret; + + ret = do_prlimit(current, resource, NULL, &value); + if (!ret) + ret = copy_to_user(rlim, &value, sizeof(*rlim)) ? -EFAULT : 0; + + return ret; +} + +#ifdef __ARCH_WANT_SYS_OLD_GETRLIMIT + +/* + * Back compatibility for getrlimit. Needed for some apps. + */ +SYSCALL_DEFINE2(old_getrlimit, unsigned int, resource, + struct rlimit __user *, rlim) +{ + struct rlimit x; + if (resource >= RLIM_NLIMITS) + return -EINVAL; + + task_lock(current->group_leader); + x = current->signal->rlim[resource]; + task_unlock(current->group_leader); + if (x.rlim_cur > 0x7FFFFFFF) + x.rlim_cur = 0x7FFFFFFF; + if (x.rlim_max > 0x7FFFFFFF) + x.rlim_max = 0x7FFFFFFF; + return copy_to_user(rlim, &x, sizeof(x)) ? -EFAULT : 0; +} + +#endif + +static inline bool rlim64_is_infinity(__u64 rlim64) +{ +#if BITS_PER_LONG < 64 + return rlim64 >= ULONG_MAX; +#else + return rlim64 == RLIM64_INFINITY; +#endif +} + +static void rlim_to_rlim64(const struct rlimit *rlim, struct rlimit64 *rlim64) +{ + if (rlim->rlim_cur == RLIM_INFINITY) + rlim64->rlim_cur = RLIM64_INFINITY; + else + rlim64->rlim_cur = rlim->rlim_cur; + if (rlim->rlim_max == RLIM_INFINITY) + rlim64->rlim_max = RLIM64_INFINITY; + else + rlim64->rlim_max = rlim->rlim_max; +} + +static void rlim64_to_rlim(const struct rlimit64 *rlim64, struct rlimit *rlim) +{ + if (rlim64_is_infinity(rlim64->rlim_cur)) + rlim->rlim_cur = RLIM_INFINITY; + else + rlim->rlim_cur = (unsigned long)rlim64->rlim_cur; + if (rlim64_is_infinity(rlim64->rlim_max)) + rlim->rlim_max = RLIM_INFINITY; + else + rlim->rlim_max = (unsigned long)rlim64->rlim_max; +} + +/* make sure you are allowed to change @tsk limits before calling this */ +int do_prlimit(struct task_struct *tsk, unsigned int resource, + struct rlimit *new_rlim, struct rlimit *old_rlim) +{ + struct rlimit *rlim; + int retval = 0; + + if (resource >= RLIM_NLIMITS) + return -EINVAL; + if (new_rlim) { + if (new_rlim->rlim_cur > new_rlim->rlim_max) + return -EINVAL; + if (resource == RLIMIT_NOFILE && + new_rlim->rlim_max > sysctl_nr_open) + return -EPERM; + } + + /* protect tsk->signal and tsk->sighand from disappearing */ + read_lock(&tasklist_lock); + if (!tsk->sighand) { + retval = -ESRCH; + goto out; + } + + rlim = tsk->signal->rlim + resource; + task_lock(tsk->group_leader); + if (new_rlim) { + /* Keep the capable check against init_user_ns until + cgroups can contain all limits */ + if (new_rlim->rlim_max > rlim->rlim_max && + !capable(CAP_SYS_RESOURCE)) + retval = -EPERM; + if (!retval) + retval = security_task_setrlimit(tsk->group_leader, + resource, new_rlim); + if (resource == RLIMIT_CPU && new_rlim->rlim_cur == 0) { + /* + * The caller is asking for an immediate RLIMIT_CPU + * expiry. But we use the zero value to mean "it was + * never set". So let's cheat and make it one second + * instead + */ + new_rlim->rlim_cur = 1; + } + } + if (!retval) { + if (old_rlim) + *old_rlim = *rlim; + if (new_rlim) + *rlim = *new_rlim; + } + task_unlock(tsk->group_leader); + + /* + * RLIMIT_CPU handling. Note that the kernel fails to return an error + * code if it rejected the user's attempt to set RLIMIT_CPU. This is a + * very long-standing error, and fixing it now risks breakage of + * applications, so we live with it + */ + if (!retval && new_rlim && resource == RLIMIT_CPU && + new_rlim->rlim_cur != RLIM_INFINITY) + update_rlimit_cpu(tsk, new_rlim->rlim_cur); +out: + read_unlock(&tasklist_lock); + return retval; +} + +/* rcu lock must be held */ +static int check_prlimit_permission(struct task_struct *task) +{ + const struct cred *cred = current_cred(), *tcred; + + if (current == task) + return 0; + + tcred = __task_cred(task); + if (uid_eq(cred->uid, tcred->euid) && + uid_eq(cred->uid, tcred->suid) && + uid_eq(cred->uid, tcred->uid) && + gid_eq(cred->gid, tcred->egid) && + gid_eq(cred->gid, tcred->sgid) && + gid_eq(cred->gid, tcred->gid)) + return 0; + if (ns_capable(tcred->user_ns, CAP_SYS_RESOURCE)) + return 0; + + return -EPERM; +} + +SYSCALL_DEFINE4(prlimit64, pid_t, pid, unsigned int, resource, + const struct rlimit64 __user *, new_rlim, + struct rlimit64 __user *, old_rlim) +{ + struct rlimit64 old64, new64; + struct rlimit old, new; + struct task_struct *tsk; + int ret; + + if (new_rlim) { + if (copy_from_user(&new64, new_rlim, sizeof(new64))) + return -EFAULT; + rlim64_to_rlim(&new64, &new); + } + + rcu_read_lock(); + tsk = pid ? find_task_by_vpid(pid) : current; + if (!tsk) { + rcu_read_unlock(); + return -ESRCH; + } + ret = check_prlimit_permission(tsk); + if (ret) { + rcu_read_unlock(); + return ret; + } + get_task_struct(tsk); + rcu_read_unlock(); + + ret = do_prlimit(tsk, resource, new_rlim ? &new : NULL, + old_rlim ? &old : NULL); + + if (!ret && old_rlim) { + rlim_to_rlim64(&old, &old64); + if (copy_to_user(old_rlim, &old64, sizeof(old64))) + ret = -EFAULT; + } + + put_task_struct(tsk); + return ret; +} + +SYSCALL_DEFINE2(setrlimit, unsigned int, resource, struct rlimit __user *, rlim) +{ + struct rlimit new_rlim; + + if (copy_from_user(&new_rlim, rlim, sizeof(*rlim))) + return -EFAULT; + return do_prlimit(current, resource, &new_rlim, NULL); +} + +/* + * It would make sense to put struct rusage in the task_struct, + * except that would make the task_struct be *really big*. After + * task_struct gets moved into malloc'ed memory, it would + * make sense to do this. It will make moving the rest of the information + * a lot simpler! (Which we're not doing right now because we're not + * measuring them yet). + * + * When sampling multiple threads for RUSAGE_SELF, under SMP we might have + * races with threads incrementing their own counters. But since word + * reads are atomic, we either get new values or old values and we don't + * care which for the sums. We always take the siglock to protect reading + * the c* fields from p->signal from races with exit.c updating those + * fields when reaping, so a sample either gets all the additions of a + * given child after it's reaped, or none so this sample is before reaping. + * + * Locking: + * We need to take the siglock for CHILDEREN, SELF and BOTH + * for the cases current multithreaded, non-current single threaded + * non-current multithreaded. Thread traversal is now safe with + * the siglock held. + * Strictly speaking, we donot need to take the siglock if we are current and + * single threaded, as no one else can take our signal_struct away, no one + * else can reap the children to update signal->c* counters, and no one else + * can race with the signal-> fields. If we do not take any lock, the + * signal-> fields could be read out of order while another thread was just + * exiting. So we should place a read memory barrier when we avoid the lock. + * On the writer side, write memory barrier is implied in __exit_signal + * as __exit_signal releases the siglock spinlock after updating the signal-> + * fields. But we don't do this yet to keep things simple. + * + */ + +static void accumulate_thread_rusage(struct task_struct *t, struct rusage *r) +{ + r->ru_nvcsw += t->nvcsw; + r->ru_nivcsw += t->nivcsw; + r->ru_minflt += t->min_flt; + r->ru_majflt += t->maj_flt; + r->ru_inblock += task_io_get_inblock(t); + r->ru_oublock += task_io_get_oublock(t); +} + +static void k_getrusage(struct task_struct *p, int who, struct rusage *r) +{ + struct task_struct *t; + unsigned long flags; + cputime_t tgutime, tgstime, utime, stime; + unsigned long maxrss = 0; + + memset((char *)r, 0, sizeof (*r)); + utime = stime = 0; + + if (who == RUSAGE_THREAD) { + task_cputime_adjusted(current, &utime, &stime); + accumulate_thread_rusage(p, r); + maxrss = p->signal->maxrss; + goto out; + } + + if (!lock_task_sighand(p, &flags)) + return; + + switch (who) { + case RUSAGE_BOTH: + case RUSAGE_CHILDREN: + utime = p->signal->cutime; + stime = p->signal->cstime; + r->ru_nvcsw = p->signal->cnvcsw; + r->ru_nivcsw = p->signal->cnivcsw; + r->ru_minflt = p->signal->cmin_flt; + r->ru_majflt = p->signal->cmaj_flt; + r->ru_inblock = p->signal->cinblock; + r->ru_oublock = p->signal->coublock; + maxrss = p->signal->cmaxrss; + + if (who == RUSAGE_CHILDREN) + break; + + case RUSAGE_SELF: + thread_group_cputime_adjusted(p, &tgutime, &tgstime); + utime += tgutime; + stime += tgstime; + r->ru_nvcsw += p->signal->nvcsw; + r->ru_nivcsw += p->signal->nivcsw; + r->ru_minflt += p->signal->min_flt; + r->ru_majflt += p->signal->maj_flt; + r->ru_inblock += p->signal->inblock; + r->ru_oublock += p->signal->oublock; + if (maxrss < p->signal->maxrss) + maxrss = p->signal->maxrss; + t = p; + do { + accumulate_thread_rusage(t, r); + } while_each_thread(p, t); + break; + + default: + BUG(); + } + unlock_task_sighand(p, &flags); + +out: + cputime_to_timeval(utime, &r->ru_utime); + cputime_to_timeval(stime, &r->ru_stime); + + if (who != RUSAGE_CHILDREN) { + struct mm_struct *mm = get_task_mm(p); + + if (mm) { + setmax_mm_hiwater_rss(&maxrss, mm); + mmput(mm); + } + } + r->ru_maxrss = maxrss * (PAGE_SIZE / 1024); /* convert pages to KBs */ +} + +int getrusage(struct task_struct *p, int who, struct rusage __user *ru) +{ + struct rusage r; + + k_getrusage(p, who, &r); + return copy_to_user(ru, &r, sizeof(r)) ? -EFAULT : 0; +} + +SYSCALL_DEFINE2(getrusage, int, who, struct rusage __user *, ru) +{ + if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN && + who != RUSAGE_THREAD) + return -EINVAL; + return getrusage(current, who, ru); +} + +#ifdef CONFIG_COMPAT +COMPAT_SYSCALL_DEFINE2(getrusage, int, who, struct compat_rusage __user *, ru) +{ + struct rusage r; + + if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN && + who != RUSAGE_THREAD) + return -EINVAL; + + k_getrusage(current, who, &r); + return put_compat_rusage(&r, ru); +} +#endif + +SYSCALL_DEFINE1(umask, int, mask) +{ + mask = xchg(¤t->fs->umask, mask & S_IRWXUGO); + return mask; +} + +static int prctl_set_mm_exe_file(struct mm_struct *mm, unsigned int fd) +{ + struct fd exe; + struct file *old_exe, *exe_file; + struct inode *inode; + int err; + + exe = fdget(fd); + if (!exe.file) + return -EBADF; + + inode = file_inode(exe.file); + + /* + * Because the original mm->exe_file points to executable file, make + * sure that this one is executable as well, to avoid breaking an + * overall picture. + */ + err = -EACCES; + if (!S_ISREG(inode->i_mode) || + exe.file->f_path.mnt->mnt_flags & MNT_NOEXEC) + goto exit; + + err = inode_permission(inode, MAY_EXEC); + if (err) + goto exit; + + /* + * Forbid mm->exe_file change if old file still mapped. + */ + exe_file = get_mm_exe_file(mm); + err = -EBUSY; + if (exe_file) { + struct vm_area_struct *vma; + + down_read(&mm->mmap_sem); + for (vma = mm->mmap; vma; vma = vma->vm_next) { + if (!vma->vm_file) + continue; + if (path_equal(&vma->vm_file->f_path, + &exe_file->f_path)) + goto exit_err; + } + + up_read(&mm->mmap_sem); + fput(exe_file); + } + + /* + * The symlink can be changed only once, just to disallow arbitrary + * transitions malicious software might bring in. This means one + * could make a snapshot over all processes running and monitor + * /proc/pid/exe changes to notice unusual activity if needed. + */ + err = -EPERM; + if (test_and_set_bit(MMF_EXE_FILE_CHANGED, &mm->flags)) + goto exit; + + err = 0; + /* set the new file, lockless */ + get_file(exe.file); + old_exe = xchg(&mm->exe_file, exe.file); + if (old_exe) + fput(old_exe); +exit: + fdput(exe); + return err; +exit_err: + up_read(&mm->mmap_sem); + fput(exe_file); + goto exit; +} + +#ifdef CONFIG_CHECKPOINT_RESTORE +/* + * WARNING: we don't require any capability here so be very careful + * in what is allowed for modification from userspace. + */ +static int validate_prctl_map(struct prctl_mm_map *prctl_map) +{ + unsigned long mmap_max_addr = TASK_SIZE; + struct mm_struct *mm = current->mm; + int error = -EINVAL, i; + + static const unsigned char offsets[] = { + offsetof(struct prctl_mm_map, start_code), + offsetof(struct prctl_mm_map, end_code), + offsetof(struct prctl_mm_map, start_data), + offsetof(struct prctl_mm_map, end_data), + offsetof(struct prctl_mm_map, start_brk), + offsetof(struct prctl_mm_map, brk), + offsetof(struct prctl_mm_map, start_stack), + offsetof(struct prctl_mm_map, arg_start), + offsetof(struct prctl_mm_map, arg_end), + offsetof(struct prctl_mm_map, env_start), + offsetof(struct prctl_mm_map, env_end), + }; + + /* + * Make sure the members are not somewhere outside + * of allowed address space. + */ + for (i = 0; i < ARRAY_SIZE(offsets); i++) { + u64 val = *(u64 *)((char *)prctl_map + offsets[i]); + + if ((unsigned long)val >= mmap_max_addr || + (unsigned long)val < mmap_min_addr) + goto out; + } + + /* + * Make sure the pairs are ordered. + */ +#define __prctl_check_order(__m1, __op, __m2) \ + ((unsigned long)prctl_map->__m1 __op \ + (unsigned long)prctl_map->__m2) ? 0 : -EINVAL + error = __prctl_check_order(start_code, <, end_code); + error |= __prctl_check_order(start_data, <, end_data); + error |= __prctl_check_order(start_brk, <=, brk); + error |= __prctl_check_order(arg_start, <=, arg_end); + error |= __prctl_check_order(env_start, <=, env_end); + if (error) + goto out; +#undef __prctl_check_order + + error = -EINVAL; + + /* + * @brk should be after @end_data in traditional maps. + */ + if (prctl_map->start_brk <= prctl_map->end_data || + prctl_map->brk <= prctl_map->end_data) + goto out; + + /* + * Neither we should allow to override limits if they set. + */ + if (check_data_rlimit(rlimit(RLIMIT_DATA), prctl_map->brk, + prctl_map->start_brk, prctl_map->end_data, + prctl_map->start_data)) + goto out; + + /* + * Someone is trying to cheat the auxv vector. + */ + if (prctl_map->auxv_size) { + if (!prctl_map->auxv || prctl_map->auxv_size > sizeof(mm->saved_auxv)) + goto out; + } + + /* + * Finally, make sure the caller has the rights to + * change /proc/pid/exe link: only local root should + * be allowed to. + */ + if (prctl_map->exe_fd != (u32)-1) { + struct user_namespace *ns = current_user_ns(); + const struct cred *cred = current_cred(); + + if (!uid_eq(cred->uid, make_kuid(ns, 0)) || + !gid_eq(cred->gid, make_kgid(ns, 0))) + goto out; + } + + error = 0; +out: + return error; +} + +static int prctl_set_mm_map(int opt, const void __user *addr, unsigned long data_size) +{ + struct prctl_mm_map prctl_map = { .exe_fd = (u32)-1, }; + unsigned long user_auxv[AT_VECTOR_SIZE]; + struct mm_struct *mm = current->mm; + int error; + + BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv)); + BUILD_BUG_ON(sizeof(struct prctl_mm_map) > 256); + + if (opt == PR_SET_MM_MAP_SIZE) + return put_user((unsigned int)sizeof(prctl_map), + (unsigned int __user *)addr); + + if (data_size != sizeof(prctl_map)) + return -EINVAL; + + if (copy_from_user(&prctl_map, addr, sizeof(prctl_map))) + return -EFAULT; + + error = validate_prctl_map(&prctl_map); + if (error) + return error; + + if (prctl_map.auxv_size) { + memset(user_auxv, 0, sizeof(user_auxv)); + if (copy_from_user(user_auxv, + (const void __user *)prctl_map.auxv, + prctl_map.auxv_size)) + return -EFAULT; + + /* Last entry must be AT_NULL as specification requires */ + user_auxv[AT_VECTOR_SIZE - 2] = AT_NULL; + user_auxv[AT_VECTOR_SIZE - 1] = AT_NULL; + } + + if (prctl_map.exe_fd != (u32)-1) + error = prctl_set_mm_exe_file(mm, prctl_map.exe_fd); + down_read(&mm->mmap_sem); + if (error) + goto out; + + /* + * We don't validate if these members are pointing to + * real present VMAs because application may have correspond + * VMAs already unmapped and kernel uses these members for statistics + * output in procfs mostly, except + * + * - @start_brk/@brk which are used in do_brk but kernel lookups + * for VMAs when updating these memvers so anything wrong written + * here cause kernel to swear at userspace program but won't lead + * to any problem in kernel itself + */ + + mm->start_code = prctl_map.start_code; + mm->end_code = prctl_map.end_code; + mm->start_data = prctl_map.start_data; + mm->end_data = prctl_map.end_data; + mm->start_brk = prctl_map.start_brk; + mm->brk = prctl_map.brk; + mm->start_stack = prctl_map.start_stack; + mm->arg_start = prctl_map.arg_start; + mm->arg_end = prctl_map.arg_end; + mm->env_start = prctl_map.env_start; + mm->env_end = prctl_map.env_end; + + /* + * Note this update of @saved_auxv is lockless thus + * if someone reads this member in procfs while we're + * updating -- it may get partly updated results. It's + * known and acceptable trade off: we leave it as is to + * not introduce additional locks here making the kernel + * more complex. + */ + if (prctl_map.auxv_size) + memcpy(mm->saved_auxv, user_auxv, sizeof(user_auxv)); + + error = 0; +out: + up_read(&mm->mmap_sem); + return error; +} +#endif /* CONFIG_CHECKPOINT_RESTORE */ + +static int prctl_set_mm(int opt, unsigned long addr, + unsigned long arg4, unsigned long arg5) +{ + struct mm_struct *mm = current->mm; + struct vm_area_struct *vma; + int error; + + if (arg5 || (arg4 && (opt != PR_SET_MM_AUXV && + opt != PR_SET_MM_MAP && + opt != PR_SET_MM_MAP_SIZE))) + return -EINVAL; + +#ifdef CONFIG_CHECKPOINT_RESTORE + if (opt == PR_SET_MM_MAP || opt == PR_SET_MM_MAP_SIZE) + return prctl_set_mm_map(opt, (const void __user *)addr, arg4); +#endif + + if (!capable(CAP_SYS_RESOURCE)) + return -EPERM; + + if (opt == PR_SET_MM_EXE_FILE) + return prctl_set_mm_exe_file(mm, (unsigned int)addr); + + if (addr >= TASK_SIZE || addr < mmap_min_addr) + return -EINVAL; + + error = -EINVAL; + + down_read(&mm->mmap_sem); + vma = find_vma(mm, addr); + + switch (opt) { + case PR_SET_MM_START_CODE: + mm->start_code = addr; + break; + case PR_SET_MM_END_CODE: + mm->end_code = addr; + break; + case PR_SET_MM_START_DATA: + mm->start_data = addr; + break; + case PR_SET_MM_END_DATA: + mm->end_data = addr; + break; + + case PR_SET_MM_START_BRK: + if (addr <= mm->end_data) + goto out; + + if (check_data_rlimit(rlimit(RLIMIT_DATA), mm->brk, addr, + mm->end_data, mm->start_data)) + goto out; + + mm->start_brk = addr; + break; + + case PR_SET_MM_BRK: + if (addr <= mm->end_data) + goto out; + + if (check_data_rlimit(rlimit(RLIMIT_DATA), addr, mm->start_brk, + mm->end_data, mm->start_data)) + goto out; + + mm->brk = addr; + break; + + /* + * If command line arguments and environment + * are placed somewhere else on stack, we can + * set them up here, ARG_START/END to setup + * command line argumets and ENV_START/END + * for environment. + */ + case PR_SET_MM_START_STACK: + case PR_SET_MM_ARG_START: + case PR_SET_MM_ARG_END: + case PR_SET_MM_ENV_START: + case PR_SET_MM_ENV_END: + if (!vma) { + error = -EFAULT; + goto out; + } + if (opt == PR_SET_MM_START_STACK) + mm->start_stack = addr; + else if (opt == PR_SET_MM_ARG_START) + mm->arg_start = addr; + else if (opt == PR_SET_MM_ARG_END) + mm->arg_end = addr; + else if (opt == PR_SET_MM_ENV_START) + mm->env_start = addr; + else if (opt == PR_SET_MM_ENV_END) + mm->env_end = addr; + break; + + /* + * This doesn't move auxiliary vector itself + * since it's pinned to mm_struct, but allow + * to fill vector with new values. It's up + * to a caller to provide sane values here + * otherwise user space tools which use this + * vector might be unhappy. + */ + case PR_SET_MM_AUXV: { + unsigned long user_auxv[AT_VECTOR_SIZE]; + + if (arg4 > sizeof(user_auxv)) + goto out; + up_read(&mm->mmap_sem); + + if (copy_from_user(user_auxv, (const void __user *)addr, arg4)) + return -EFAULT; + + /* Make sure the last entry is always AT_NULL */ + user_auxv[AT_VECTOR_SIZE - 2] = 0; + user_auxv[AT_VECTOR_SIZE - 1] = 0; + + BUILD_BUG_ON(sizeof(user_auxv) != sizeof(mm->saved_auxv)); + + task_lock(current); + memcpy(mm->saved_auxv, user_auxv, arg4); + task_unlock(current); + + return 0; + } + default: + goto out; + } + + error = 0; +out: + up_read(&mm->mmap_sem); + return error; +} + +#ifdef CONFIG_CHECKPOINT_RESTORE +static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr) +{ + return put_user(me->clear_child_tid, tid_addr); +} +#else +static int prctl_get_tid_address(struct task_struct *me, int __user **tid_addr) +{ + return -EINVAL; +} +#endif + +SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3, + unsigned long, arg4, unsigned long, arg5) +{ + struct task_struct *me = current; + unsigned char comm[sizeof(me->comm)]; + long error; + + error = security_task_prctl(option, arg2, arg3, arg4, arg5); + if (error != -ENOSYS) + return error; + + error = 0; + switch (option) { + case PR_SET_PDEATHSIG: + if (!valid_signal(arg2)) { + error = -EINVAL; + break; + } + me->pdeath_signal = arg2; + break; + case PR_GET_PDEATHSIG: + error = put_user(me->pdeath_signal, (int __user *)arg2); + break; + case PR_GET_DUMPABLE: + error = get_dumpable(me->mm); + break; + case PR_SET_DUMPABLE: + if (arg2 != SUID_DUMP_DISABLE && arg2 != SUID_DUMP_USER) { + error = -EINVAL; + break; + } + set_dumpable(me->mm, arg2); + break; + + case PR_SET_UNALIGN: + error = SET_UNALIGN_CTL(me, arg2); + break; + case PR_GET_UNALIGN: + error = GET_UNALIGN_CTL(me, arg2); + break; + case PR_SET_FPEMU: + error = SET_FPEMU_CTL(me, arg2); + break; + case PR_GET_FPEMU: + error = GET_FPEMU_CTL(me, arg2); + break; + case PR_SET_FPEXC: + error = SET_FPEXC_CTL(me, arg2); + break; + case PR_GET_FPEXC: + error = GET_FPEXC_CTL(me, arg2); + break; + case PR_GET_TIMING: + error = PR_TIMING_STATISTICAL; + break; + case PR_SET_TIMING: + if (arg2 != PR_TIMING_STATISTICAL) + error = -EINVAL; + break; + case PR_SET_NAME: + comm[sizeof(me->comm) - 1] = 0; + if (strncpy_from_user(comm, (char __user *)arg2, + sizeof(me->comm) - 1) < 0) + return -EFAULT; + set_task_comm(me, comm); + proc_comm_connector(me); + break; + case PR_GET_NAME: + get_task_comm(comm, me); + if (copy_to_user((char __user *)arg2, comm, sizeof(comm))) + return -EFAULT; + break; + case PR_GET_ENDIAN: + error = GET_ENDIAN(me, arg2); + break; + case PR_SET_ENDIAN: + error = SET_ENDIAN(me, arg2); + break; + case PR_GET_SECCOMP: + error = prctl_get_seccomp(); + break; + case PR_SET_SECCOMP: + error = prctl_set_seccomp(arg2, (char __user *)arg3); + break; + case PR_GET_TSC: + error = GET_TSC_CTL(arg2); + break; + case PR_SET_TSC: + error = SET_TSC_CTL(arg2); + break; + case PR_TASK_PERF_EVENTS_DISABLE: + error = perf_event_task_disable(); + break; + case PR_TASK_PERF_EVENTS_ENABLE: + error = perf_event_task_enable(); + break; + case PR_GET_TIMERSLACK: + error = current->timer_slack_ns; + break; + case PR_SET_TIMERSLACK: + if (arg2 <= 0) + current->timer_slack_ns = + current->default_timer_slack_ns; + else + current->timer_slack_ns = arg2; + break; + case PR_MCE_KILL: + if (arg4 | arg5) + return -EINVAL; + switch (arg2) { + case PR_MCE_KILL_CLEAR: + if (arg3 != 0) + return -EINVAL; + current->flags &= ~PF_MCE_PROCESS; + break; + case PR_MCE_KILL_SET: + current->flags |= PF_MCE_PROCESS; + if (arg3 == PR_MCE_KILL_EARLY) + current->flags |= PF_MCE_EARLY; + else if (arg3 == PR_MCE_KILL_LATE) + current->flags &= ~PF_MCE_EARLY; + else if (arg3 == PR_MCE_KILL_DEFAULT) + current->flags &= + ~(PF_MCE_EARLY|PF_MCE_PROCESS); + else + return -EINVAL; + break; + default: + return -EINVAL; + } + break; + case PR_MCE_KILL_GET: + if (arg2 | arg3 | arg4 | arg5) + return -EINVAL; + if (current->flags & PF_MCE_PROCESS) + error = (current->flags & PF_MCE_EARLY) ? + PR_MCE_KILL_EARLY : PR_MCE_KILL_LATE; + else + error = PR_MCE_KILL_DEFAULT; + break; + case PR_SET_MM: + error = prctl_set_mm(arg2, arg3, arg4, arg5); + break; + case PR_GET_TID_ADDRESS: + error = prctl_get_tid_address(me, (int __user **)arg2); + break; + case PR_SET_CHILD_SUBREAPER: + me->signal->is_child_subreaper = !!arg2; + break; + case PR_GET_CHILD_SUBREAPER: + error = put_user(me->signal->is_child_subreaper, + (int __user *)arg2); + break; + case PR_SET_NO_NEW_PRIVS: + if (arg2 != 1 || arg3 || arg4 || arg5) + return -EINVAL; + + task_set_no_new_privs(current); + break; + case PR_GET_NO_NEW_PRIVS: + if (arg2 || arg3 || arg4 || arg5) + return -EINVAL; + return task_no_new_privs(current) ? 1 : 0; + case PR_GET_THP_DISABLE: + if (arg2 || arg3 || arg4 || arg5) + return -EINVAL; + error = !!(me->mm->def_flags & VM_NOHUGEPAGE); + break; + case PR_SET_THP_DISABLE: + if (arg3 || arg4 || arg5) + return -EINVAL; + down_write(&me->mm->mmap_sem); + if (arg2) + me->mm->def_flags |= VM_NOHUGEPAGE; + else + me->mm->def_flags &= ~VM_NOHUGEPAGE; + up_write(&me->mm->mmap_sem); + break; + case PR_MPX_ENABLE_MANAGEMENT: + if (arg2 || arg3 || arg4 || arg5) + return -EINVAL; + error = MPX_ENABLE_MANAGEMENT(me); + break; + case PR_MPX_DISABLE_MANAGEMENT: + if (arg2 || arg3 || arg4 || arg5) + return -EINVAL; + error = MPX_DISABLE_MANAGEMENT(me); + break; + case PR_SET_FP_MODE: + error = SET_FP_MODE(me, arg2); + break; + case PR_GET_FP_MODE: + error = GET_FP_MODE(me); + break; + default: + error = -EINVAL; + break; + } + return error; +} + +SYSCALL_DEFINE3(getcpu, unsigned __user *, cpup, unsigned __user *, nodep, + struct getcpu_cache __user *, unused) +{ + int err = 0; + int cpu = raw_smp_processor_id(); + + if (cpup) + err |= put_user(cpu, cpup); + if (nodep) + err |= put_user(cpu_to_node(cpu), nodep); + return err ? -EFAULT : 0; +} + +/** + * do_sysinfo - fill in sysinfo struct + * @info: pointer to buffer to fill + */ +static int do_sysinfo(struct sysinfo *info) +{ + unsigned long mem_total, sav_total; + unsigned int mem_unit, bitcount; + struct timespec tp; + + memset(info, 0, sizeof(struct sysinfo)); + + get_monotonic_boottime(&tp); + info->uptime = tp.tv_sec + (tp.tv_nsec ? 1 : 0); + + get_avenrun(info->loads, 0, SI_LOAD_SHIFT - FSHIFT); + + info->procs = nr_threads; + + si_meminfo(info); + si_swapinfo(info); + + /* + * If the sum of all the available memory (i.e. ram + swap) + * is less than can be stored in a 32 bit unsigned long then + * we can be binary compatible with 2.2.x kernels. If not, + * well, in that case 2.2.x was broken anyways... + * + * -Erik Andersen <andersee@debian.org> + */ + + mem_total = info->totalram + info->totalswap; + if (mem_total < info->totalram || mem_total < info->totalswap) + goto out; + bitcount = 0; + mem_unit = info->mem_unit; + while (mem_unit > 1) { + bitcount++; + mem_unit >>= 1; + sav_total = mem_total; + mem_total <<= 1; + if (mem_total < sav_total) + goto out; + } + + /* + * If mem_total did not overflow, multiply all memory values by + * info->mem_unit and set it to 1. This leaves things compatible + * with 2.2.x, and also retains compatibility with earlier 2.4.x + * kernels... + */ + + info->mem_unit = 1; + info->totalram <<= bitcount; + info->freeram <<= bitcount; + info->sharedram <<= bitcount; + info->bufferram <<= bitcount; + info->totalswap <<= bitcount; + info->freeswap <<= bitcount; + info->totalhigh <<= bitcount; + info->freehigh <<= bitcount; + +out: + return 0; +} + +SYSCALL_DEFINE1(sysinfo, struct sysinfo __user *, info) +{ + struct sysinfo val; + + do_sysinfo(&val); + + if (copy_to_user(info, &val, sizeof(struct sysinfo))) + return -EFAULT; + + return 0; +} + +#ifdef CONFIG_COMPAT +struct compat_sysinfo { + s32 uptime; + u32 loads[3]; + u32 totalram; + u32 freeram; + u32 sharedram; + u32 bufferram; + u32 totalswap; + u32 freeswap; + u16 procs; + u16 pad; + u32 totalhigh; + u32 freehigh; + u32 mem_unit; + char _f[20-2*sizeof(u32)-sizeof(int)]; +}; + +COMPAT_SYSCALL_DEFINE1(sysinfo, struct compat_sysinfo __user *, info) +{ + struct sysinfo s; + + do_sysinfo(&s); + + /* Check to see if any memory value is too large for 32-bit and scale + * down if needed + */ + if (upper_32_bits(s.totalram) || upper_32_bits(s.totalswap)) { + int bitcount = 0; + + while (s.mem_unit < PAGE_SIZE) { + s.mem_unit <<= 1; + bitcount++; + } + + s.totalram >>= bitcount; + s.freeram >>= bitcount; + s.sharedram >>= bitcount; + s.bufferram >>= bitcount; + s.totalswap >>= bitcount; + s.freeswap >>= bitcount; + s.totalhigh >>= bitcount; + s.freehigh >>= bitcount; + } + + if (!access_ok(VERIFY_WRITE, info, sizeof(struct compat_sysinfo)) || + __put_user(s.uptime, &info->uptime) || + __put_user(s.loads[0], &info->loads[0]) || + __put_user(s.loads[1], &info->loads[1]) || + __put_user(s.loads[2], &info->loads[2]) || + __put_user(s.totalram, &info->totalram) || + __put_user(s.freeram, &info->freeram) || + __put_user(s.sharedram, &info->sharedram) || + __put_user(s.bufferram, &info->bufferram) || + __put_user(s.totalswap, &info->totalswap) || + __put_user(s.freeswap, &info->freeswap) || + __put_user(s.procs, &info->procs) || + __put_user(s.totalhigh, &info->totalhigh) || + __put_user(s.freehigh, &info->freehigh) || + __put_user(s.mem_unit, &info->mem_unit)) + return -EFAULT; + + return 0; +} +#endif /* CONFIG_COMPAT */ |