167 lines
3.7 KiB
C
Executable file
167 lines
3.7 KiB
C
Executable file
#include "sysincludes.h"
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#include "msdos.h"
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#include "mtools.h"
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/*#define PRIV_DEBUG*/
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#if 0
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#undef HAVE_SETEUID
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#define HAVE_SETRESUID
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#include <asm/unistd.h>
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int setresuid(int a, int b, int c)
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{
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syscall(164, a, b, c);
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}
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#endif
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static inline void print_privs(const char *message)
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{
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#ifdef PRIV_DEBUG
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/* for debugging purposes only */
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fprintf(stderr,"%s egid=%d rgid=%d\n", message, getegid(), getgid());
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fprintf(stderr,"%s euid=%d ruid=%d\n", message, geteuid(), getuid());
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#endif
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}
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int noPrivileges=0;
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static gid_t rgid, egid;
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static uid_t ruid, euid;
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/* privilege management routines for SunOS and Solaris. These are
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* needed in order to issue raw SCSI read/write ioctls. Mtools drops
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* its privileges at the beginning, and reclaims them just for the
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* above-mentioned ioctl's. Before popen(), exec() or system, it
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* drops its privileges completely, and issues a warning.
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*/
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/* group id handling is lots easyer, as long as we don't use group 0.
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* If you want to use group id's, create a *new* group mtools or
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* floppy. Chgrp any devices that you only want to be accessible to
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* mtools to this group, and give them the appropriate privs. Make
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* sure this group doesn't own any other files: be aware that any user
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* with access to mtools may mformat these files!
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*/
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static inline void Setuid(uid_t uid)
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{
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#if defined HAVE_SETEUID || defined HAVE_SETRESUID
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if(euid == 0) {
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#ifdef HAVE_SETEUID
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seteuid(uid);
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#else
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setresuid(ruid, uid, euid);
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#endif
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} else
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#endif
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setuid(uid);
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}
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/* In reclaim_privs and drop privs, we have to manipulate group privileges
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* when having no root privileges, else we might lose them */
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void reclaim_privs(void)
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{
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if(noPrivileges)
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return;
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setgid(egid);
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Setuid(euid);
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print_privs("after reclaim privs, both uids should be 0 ");
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}
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void drop_privs(void)
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{
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Setuid(ruid);
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setgid(rgid);
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print_privs("after drop_privs, real should be 0, effective should not ");
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}
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void destroy_privs(void)
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{
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#if defined HAVE_SETEUID || defined HAVE_SETRESUID
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if(euid == 0) {
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#ifdef HAVE_SETEUID
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setuid(0); /* get the necessary privs to drop real root id */
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setuid(ruid); /* this should be enough to get rid of the three
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* ids */
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seteuid(ruid); /* for good measure... just in case we came
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* accross a system which implemented sane
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* semantics instead of POSIXly broken
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* semantics for setuid */
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#else
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setresuid(ruid, ruid, ruid);
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#endif
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}
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#endif
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/* we also destroy group privileges */
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drop_privs();
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/* saved set [ug]id will go away by itself on exec */
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print_privs("destroy_privs, no uid should be zero ");
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}
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uid_t get_real_uid(void)
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{
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return ruid;
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}
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void init_privs(void)
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{
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euid = geteuid();
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ruid = getuid();
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egid = getegid();
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rgid = getgid();
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#ifndef F_SETFD
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if(euid != ruid) {
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fprintf(stderr,
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"Setuid installation not supported on this platform\n");
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fprintf(stderr,
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"Missing F_SETFD");
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exit(1);
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}
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#endif
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if(euid == 0 && ruid != 0) {
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#ifdef HAVE_SETEUID
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setuid(0); /* set real uid to 0 */
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#else
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#ifndef HAVE_SETRESUID
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/* on this machine, it is not possible to reversibly drop
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* root privileges. We print an error and quit */
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/* BEOS is no longer a special case, as both euid and ruid
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* return 0, and thus we do not get any longer into this
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* branch */
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fprintf(stderr,
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"Seteuid call not supported on this architecture.\n");
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fprintf(stderr,
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"Mtools cannot be installed setuid root.\n");
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fprintf(stderr,
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"However, it can be installed setuid to a non root");
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fprintf(stderr,
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"user or setgid to any id.\n");
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exit(1);
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#endif
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#endif
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}
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drop_privs();
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print_privs("after init, real should be 0, effective should not ");
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}
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void closeExec(int fd)
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{
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#ifdef F_SETFD
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fcntl(fd, F_SETFD, 1);
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#endif
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}
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