/* * linux/kernel/sys.c * * Copyright (C) 1991, 1992 Linus Torvalds */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include /* * this indicates whether you can reboot with ctrl-alt-del: the default is yes */ static int C_A_D = 1; extern void adjust_clock(void); #define PZERO 15 asmlinkage int sys_ni_syscall(void) { return -ENOSYS; } static int proc_sel(struct task_struct *p, int which, int who) { switch (which) { case PRIO_PROCESS: if (!who && p == current) return 1; return(p->pid == who); case PRIO_PGRP: if (!who) who = current->pgrp; return(p->pgrp == who); case PRIO_USER: if (!who) who = current->uid; return(p->uid == who); } return 0; } asmlinkage int sys_setpriority(int which, int who, int niceval) { struct task_struct **p; int error = ESRCH; int priority; if (which > 2 || which < 0) return -EINVAL; if ((priority = PZERO - niceval) <= 0) priority = 1; for(p = &LAST_TASK; p > &FIRST_TASK; --p) { if (!*p || !proc_sel(*p, which, who)) continue; if ((*p)->uid != current->euid && (*p)->uid != current->uid && !suser()) { error = EPERM; continue; } if (error == ESRCH) error = 0; if (priority > (*p)->priority && !suser()) error = EACCES; else (*p)->priority = priority; } return -error; } asmlinkage int sys_getpriority(int which, int who) { struct task_struct **p; int max_prio = 0; if (which > 2 || which < 0) return -EINVAL; for(p = &LAST_TASK; p > &FIRST_TASK; --p) { if (!*p || !proc_sel(*p, which, who)) continue; if ((*p)->priority > max_prio) max_prio = (*p)->priority; } return(max_prio ? max_prio : -ESRCH); } asmlinkage int sys_profil(void) { return -ENOSYS; } asmlinkage int sys_ftime(void) { return -ENOSYS; } asmlinkage int sys_break(void) { return -ENOSYS; } asmlinkage int sys_stty(void) { return -ENOSYS; } asmlinkage int sys_gtty(void) { return -ENOSYS; } asmlinkage int sys_prof(void) { return -ENOSYS; } extern void hard_reset_now(void); extern asmlinkage sys_kill(int, int); /* * Reboot system call: for obvious reasons only root may call it, * and even root needs to set up some magic numbers in the registers * so that some mistake won't make this reboot the whole machine. * You can also set the meaning of the ctrl-alt-del-key here. * * reboot doesn't sync: do that yourself before calling this. */ asmlinkage int sys_reboot(int magic, int magic_too, int flag) { if (!suser()) return -EPERM; if (magic != 0xfee1dead || magic_too != 672274793) return -EINVAL; if (flag == 0x01234567) hard_reset_now(); else if (flag == 0x89ABCDEF) C_A_D = 1; else if (!flag) C_A_D = 0; else if (flag == 0xCDEF0123) { printk(KERN_EMERG "System halted\n"); sys_kill(-1, SIGKILL); do_exit(0); } else return -EINVAL; return (0); } /* * This function gets called by ctrl-alt-del - ie the keyboard interrupt. * As it's called within an interrupt, it may NOT sync: the only choice * is whether to reboot at once, or just ignore the ctrl-alt-del. */ void ctrl_alt_del(void) { if (C_A_D) hard_reset_now(); else send_sig(SIGINT,task[1],1); } /* * 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 w/ Saved ID's. */ asmlinkage int sys_setregid(gid_t rgid, gid_t egid) { int old_rgid = current->gid; int old_egid = current->egid; if (rgid != (gid_t) -1) { if ((old_rgid == rgid) || (current->egid==rgid) || suser()) current->gid = rgid; else return(-EPERM); } if (egid != (gid_t) -1) { if ((old_rgid == egid) || (current->egid == egid) || (current->sgid == egid) || suser()) current->egid = egid; else { current->gid = old_rgid; return(-EPERM); } } if (rgid != (gid_t) -1 || (egid != (gid_t) -1 && egid != old_rgid)) current->sgid = current->egid; current->fsgid = current->egid; if (current->egid != old_egid) current->dumpable = 0; return 0; } /* * setgid() is implemented like SysV w/ SAVED_IDS */ asmlinkage int sys_setgid(gid_t gid) { int old_egid = current->egid; if (suser()) current->gid = current->egid = current->sgid = current->fsgid = gid; else if ((gid == current->gid) || (gid == current->sgid)) current->egid = current->fsgid = gid; else return -EPERM; if (current->egid != old_egid) current->dumpable = 0; return 0; } asmlinkage int sys_acct(void) { return -ENOSYS; } asmlinkage int sys_phys(void) { return -ENOSYS; } asmlinkage int sys_lock(void) { return -ENOSYS; } asmlinkage int sys_mpx(void) { return -ENOSYS; } asmlinkage int sys_ulimit(void) { return -ENOSYS; } asmlinkage int sys_old_syscall(void) { return -ENOSYS; } /* * 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 w/ Saved ID's. */ asmlinkage int sys_setreuid(uid_t ruid, uid_t euid) { int old_ruid = current->uid; int old_euid = current->euid; if (ruid != (uid_t) -1) { if ((old_ruid == ruid) || (current->euid==ruid) || suser()) current->uid = ruid; else return(-EPERM); } if (euid != (uid_t) -1) { if ((old_ruid == euid) || (current->euid == euid) || (current->suid == euid) || suser()) current->euid = euid; else { current->uid = old_ruid; return(-EPERM); } } if (ruid != (uid_t) -1 || (euid != (uid_t) -1 && euid != old_ruid)) current->suid = current->euid; current->fsuid = current->euid; if (current->euid != old_euid) current->dumpable = 0; return 0; } /* * setuid() is implemented like SysV w/ 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. */ asmlinkage int sys_setuid(uid_t uid) { int old_euid = current->euid; if (suser()) current->uid = current->euid = current->suid = current->fsuid = uid; else if ((uid == current->uid) || (uid == current->suid)) current->fsuid = current->euid = uid; else return -EPERM; if (current->euid != old_euid) current->dumpable = 0; return(0); } /* * "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.. */ asmlinkage int sys_setfsuid(uid_t uid) { int old_fsuid = current->fsuid; if (uid == current->uid || uid == current->euid || uid == current->suid || uid == current->fsuid || suser()) current->fsuid = uid; if (current->fsuid != old_fsuid) current->dumpable = 0; return old_fsuid; } /* * Samma på svenska.. */ asmlinkage int sys_setfsgid(gid_t gid) { int old_fsgid = current->fsgid; if (gid == current->gid || gid == current->egid || gid == current->sgid || gid == current->fsgid || suser()) current->fsgid = gid; if (current->fsgid != old_fsgid) current->dumpable = 0; return old_fsgid; } asmlinkage int sys_times(struct tms * tbuf) { if (tbuf) { int error = verify_area(VERIFY_WRITE,tbuf,sizeof *tbuf); if (error) return error; put_user(current->utime,&tbuf->tms_utime); put_user(current->stime,&tbuf->tms_stime); put_user(current->cutime,&tbuf->tms_cutime); put_user(current->cstime,&tbuf->tms_cstime); } return jiffies; } asmlinkage unsigned long sys_brk(unsigned long brk) { int freepages; unsigned long rlim; unsigned long newbrk, oldbrk; if (brk < current->mm->end_code) return current->mm->brk; newbrk = PAGE_ALIGN(brk); oldbrk = PAGE_ALIGN(current->mm->brk); if (oldbrk == newbrk) return current->mm->brk = brk; /* * Always allow shrinking brk */ if (brk <= current->mm->brk) { current->mm->brk = brk; do_munmap(newbrk, oldbrk-newbrk); return brk; } /* * Check against rlimit and stack.. */ rlim = current->rlim[RLIMIT_DATA].rlim_cur; if (rlim >= RLIM_INFINITY) rlim = ~0; if (brk - current->mm->end_code > rlim) return current->mm->brk; /* * Check against existing mmap mappings. */ if (find_vma_intersection(current, oldbrk, newbrk+PAGE_SIZE)) return current->mm->brk; /* * stupid algorithm to decide if we have enough memory: while * simple, it hopefully works in most obvious cases.. Easy to * fool it, but this should catch most mistakes. */ freepages = buffermem >> 12; freepages += nr_free_pages; freepages += nr_swap_pages; freepages -= MAP_NR(high_memory) >> 4; freepages -= (newbrk-oldbrk) >> 12; if (freepages < 0) return current->mm->brk; #if 0 freepages += current->mm->rss; freepages -= oldbrk >> 12; if (freepages < 0) return current->mm->brk; #endif /* * Ok, we have probably got enough memory - let it rip. */ current->mm->brk = brk; do_mmap(NULL, oldbrk, newbrk-oldbrk, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_FIXED|MAP_PRIVATE, 0); return brk; } /* * 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 * * Auch. Had to add the 'did_exec' flag to conform completely to POSIX. * LBT 04.03.94 */ asmlinkage int sys_setpgid(pid_t pid, pid_t pgid) { struct task_struct * p; if (!pid) pid = current->pid; if (!pgid) pgid = pid; if (pgid < 0) return -EINVAL; for_each_task(p) { if (p->pid == pid) goto found_task; } return -ESRCH; found_task: if (p->p_pptr == current || p->p_opptr == current) { if (p->session != current->session) return -EPERM; if (p->did_exec) return -EACCES; } else if (p != current) return -ESRCH; if (p->leader) return -EPERM; if (pgid != pid) { struct task_struct * tmp; for_each_task (tmp) { if (tmp->pgrp == pgid && tmp->session == current->session) goto ok_pgid; } return -EPERM; } ok_pgid: p->pgrp = pgid; return 0; } asmlinkage int sys_getpgid(pid_t pid) { struct task_struct * p; if (!pid) return current->pgrp; for_each_task(p) { if (p->pid == pid) return p->pgrp; } return -ESRCH; } asmlinkage int sys_getpgrp(void) { return current->pgrp; } asmlinkage int sys_setsid(void) { if (current->leader) return -EPERM; current->leader = 1; current->session = current->pgrp = current->pid; current->tty = NULL; current->tty_old_pgrp = 0; return current->pgrp; } /* * Supplementary group ID's */ asmlinkage int sys_getgroups(int gidsetsize, gid_t *grouplist) { int i; int * groups; if (gidsetsize) { i = verify_area(VERIFY_WRITE, grouplist, sizeof(gid_t) * gidsetsize); if (i) return i; } groups = current->groups; for (i = 0 ; (i < NGROUPS) && (*groups != NOGROUP) ; i++, groups++) { if (!gidsetsize) continue; if (i >= gidsetsize) break; put_user(*groups, grouplist); grouplist++; } return(i); } asmlinkage int sys_setgroups(int gidsetsize, gid_t *grouplist) { int i; if (!suser()) return -EPERM; if (gidsetsize > NGROUPS) return -EINVAL; i = verify_area(VERIFY_READ, grouplist, sizeof(gid_t) * gidsetsize); if (i) return i; for (i = 0; i < gidsetsize; i++, grouplist++) { current->groups[i] = get_user(grouplist); } if (i < NGROUPS) current->groups[i] = NOGROUP; return 0; } int in_group_p(gid_t grp) { int i; if (grp == current->fsgid) return 1; for (i = 0; i < NGROUPS; i++) { if (current->groups[i] == NOGROUP) break; if (current->groups[i] == grp) return 1; } return 0; } asmlinkage int sys_newuname(struct new_utsname * name) { int error; if (!name) return -EFAULT; error = verify_area(VERIFY_WRITE, name, sizeof *name); if (!error) memcpy_tofs(name,&system_utsname,sizeof *name); return error; } asmlinkage int sys_uname(struct old_utsname * name) { int error; if (!name) return -EFAULT; error = verify_area(VERIFY_WRITE, name,sizeof *name); if (error) return error; memcpy_tofs(&name->sysname,&system_utsname.sysname, sizeof (system_utsname.sysname)); memcpy_tofs(&name->nodename,&system_utsname.nodename, sizeof (system_utsname.nodename)); memcpy_tofs(&name->release,&system_utsname.release, sizeof (system_utsname.release)); memcpy_tofs(&name->version,&system_utsname.version, sizeof (system_utsname.version)); memcpy_tofs(&name->machine,&system_utsname.machine, sizeof (system_utsname.machine)); return 0; } asmlinkage int sys_olduname(struct oldold_utsname * name) { int error; if (!name) return -EFAULT; error = verify_area(VERIFY_WRITE, name,sizeof *name); if (error) return error; memcpy_tofs(&name->sysname,&system_utsname.sysname,__OLD_UTS_LEN); put_user(0,name->sysname+__OLD_UTS_LEN); memcpy_tofs(&name->nodename,&system_utsname.nodename,__OLD_UTS_LEN); put_user(0,name->nodename+__OLD_UTS_LEN); memcpy_tofs(&name->release,&system_utsname.release,__OLD_UTS_LEN); put_user(0,name->release+__OLD_UTS_LEN); memcpy_tofs(&name->version,&system_utsname.version,__OLD_UTS_LEN); put_user(0,name->version+__OLD_UTS_LEN); memcpy_tofs(&name->machine,&system_utsname.machine,__OLD_UTS_LEN); put_user(0,name->machine+__OLD_UTS_LEN); return 0; } asmlinkage int sys_sethostname(char *name, int len) { int error; if (!suser()) return -EPERM; if (len < 0 || len > __NEW_UTS_LEN) return -EINVAL; error = verify_area(VERIFY_READ, name, len); if (error) return error; memcpy_fromfs(system_utsname.nodename, name, len); system_utsname.nodename[len] = 0; return 0; } asmlinkage int sys_gethostname(char *name, int len) { int i; if (len < 0) return -EINVAL; i = verify_area(VERIFY_WRITE, name, len); if (i) return i; i = 1+strlen(system_utsname.nodename); if (i > len) i = len; memcpy_tofs(name, system_utsname.nodename, i); return 0; } /* * Only setdomainname; getdomainname can be implemented by calling * uname() */ asmlinkage int sys_setdomainname(char *name, int len) { int error; if (!suser()) return -EPERM; if (len > __NEW_UTS_LEN) return -EINVAL; error = verify_area(VERIFY_READ, name, len); if (error) return error; memcpy_fromfs(system_utsname.domainname, name, len); system_utsname.domainname[len] = 0; return 0; } asmlinkage int sys_getrlimit(unsigned int resource, struct rlimit *rlim) { int error; if (resource >= RLIM_NLIMITS) return -EINVAL; error = verify_area(VERIFY_WRITE,rlim,sizeof *rlim); if (error) return error; memcpy_tofs(rlim, current->rlim + resource, sizeof(*rlim)); return 0; } asmlinkage int sys_setrlimit(unsigned int resource, struct rlimit *rlim) { struct rlimit new_rlim, *old_rlim; int err; if (resource >= RLIM_NLIMITS) return -EINVAL; err = verify_area(VERIFY_READ, rlim, sizeof(*rlim)); if (err) return err; memcpy_fromfs(&new_rlim, rlim, sizeof(*rlim)); old_rlim = current->rlim + resource; if (((new_rlim.rlim_cur > old_rlim->rlim_max) || (new_rlim.rlim_max > old_rlim->rlim_max)) && !suser()) return -EPERM; if (resource == RLIMIT_NOFILE) { if (new_rlim.rlim_cur > NR_OPEN || new_rlim.rlim_max > NR_OPEN) return -EPERM; } *old_rlim = new_rlim; return 0; } /* * 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). */ int getrusage(struct task_struct *p, int who, struct rusage *ru) { int error; struct rusage r; error = verify_area(VERIFY_WRITE, ru, sizeof *ru); if (error) return error; memset((char *) &r, 0, sizeof(r)); switch (who) { case RUSAGE_SELF: r.ru_utime.tv_sec = CT_TO_SECS(p->utime); r.ru_utime.tv_usec = CT_TO_USECS(p->utime); r.ru_stime.tv_sec = CT_TO_SECS(p->stime); r.ru_stime.tv_usec = CT_TO_USECS(p->stime); r.ru_minflt = p->mm->min_flt; r.ru_majflt = p->mm->maj_flt; break; case RUSAGE_CHILDREN: r.ru_utime.tv_sec = CT_TO_SECS(p->cutime); r.ru_utime.tv_usec = CT_TO_USECS(p->cutime); r.ru_stime.tv_sec = CT_TO_SECS(p->cstime); r.ru_stime.tv_usec = CT_TO_USECS(p->cstime); r.ru_minflt = p->mm->cmin_flt; r.ru_majflt = p->mm->cmaj_flt; break; default: r.ru_utime.tv_sec = CT_TO_SECS(p->utime + p->cutime); r.ru_utime.tv_usec = CT_TO_USECS(p->utime + p->cutime); r.ru_stime.tv_sec = CT_TO_SECS(p->stime + p->cstime); r.ru_stime.tv_usec = CT_TO_USECS(p->stime + p->cstime); r.ru_minflt = p->mm->min_flt + p->mm->cmin_flt; r.ru_majflt = p->mm->maj_flt + p->mm->cmaj_flt; break; } memcpy_tofs(ru, &r, sizeof(r)); return 0; } asmlinkage int sys_getrusage(int who, struct rusage *ru) { if (who != RUSAGE_SELF && who != RUSAGE_CHILDREN) return -EINVAL; return getrusage(current, who, ru); } asmlinkage int sys_umask(int mask) { int old = current->fs->umask; current->fs->umask = mask & S_IRWXUGO; return (old); }