diff options
Diffstat (limited to 'uidswap.c')
-rw-r--r-- | uidswap.c | 47 |
1 files changed, 40 insertions, 7 deletions
@@ -26,14 +26,18 @@ RCSID("$OpenBSD: uidswap.c,v 1.16 2001/04/20 16:32:22 markus Exp $"); * POSIX saved uids or not. */ +#if defined(_POSIX_SAVED_IDS) && !defined(BROKEN_SAVED_UIDS) /* Lets assume that posix saved ids also work with seteuid, even though that is not part of the posix specification. */ +#define SAVED_IDS_WORK_WITH_SETEUID +/* Saved effective uid. */ +static uid_t saved_euid = 0; +static gid_t saved_egid = 0; +#endif /* Saved effective uid. */ static int privileged = 0; static int temporarily_use_uid_effective = 0; -static uid_t saved_euid = 0; -static gid_t saved_egid; static gid_t saved_egroups[NGROUPS_MAX], user_groups[NGROUPS_MAX]; static int saved_egroupslen = -1, user_groupslen = -1; @@ -45,16 +49,24 @@ void temporarily_use_uid(struct passwd *pw) { /* Save the current euid, and egroups. */ +#ifdef SAVED_IDS_WORK_WITH_SETEUID saved_euid = geteuid(); + saved_egid = getegid(); debug("temporarily_use_uid: %d/%d (e=%d)", pw->pw_uid, pw->pw_gid, saved_euid); if (saved_euid != 0) { privileged = 0; return; } +#else + if (geteuid() != 0) { + privileged = 0; + return; + } +#endif /* SAVED_IDS_WORK_WITH_SETEUID */ + privileged = 1; temporarily_use_uid_effective = 1; - saved_egid = getegid(); saved_egroupslen = getgroups(NGROUPS_MAX, saved_egroups); if (saved_egroupslen < 0) fatal("getgroups: %.100s", strerror(errno)); @@ -71,7 +83,14 @@ temporarily_use_uid(struct passwd *pw) /* Set the effective uid to the given (unprivileged) uid. */ if (setgroups(user_groupslen, user_groups) < 0) fatal("setgroups: %.100s", strerror(errno)); - pw->pw_gid = pw->pw_gid; +#ifndef SAVED_IDS_WORK_WITH_SETEUID + /* Propagate the privileged gid to all of our gids. */ + if (setgid(getegid()) < 0) + debug("setgid %u: %.100s", (u_int) getegid(), strerror(errno)); + /* Propagate the privileged uid to all of our uids. */ + if (setuid(geteuid()) < 0) + debug("setuid %u: %.100s", (u_int) geteuid(), strerror(errno)); +#endif /* SAVED_IDS_WORK_WITH_SETEUID */ if (setegid(pw->pw_gid) < 0) fatal("setegid %u: %.100s", (u_int) pw->pw_gid, strerror(errno)); @@ -92,13 +111,27 @@ restore_uid(void) return; if (!temporarily_use_uid_effective) fatal("restore_uid: temporarily_use_uid not effective"); + +#ifdef SAVED_IDS_WORK_WITH_SETEUID /* Set the effective uid back to the saved privileged uid. */ if (seteuid(saved_euid) < 0) - fatal("seteuid %u: %.100s", (u_int) saved_euid, strerror(errno)); + fatal("seteuid %u: %.100s", (u_int) saved_euid, + strerror(errno)); + if (setegid(saved_egid) < 0) + fatal("setegid %u: %.100s", (u_int) saved_egid, + strerror(errno)); +#else /* SAVED_IDS_WORK_WITH_SETEUID */ + /* + * We are unable to restore the real uid to its unprivileged value. + * Propagate the real uid (usually more privileged) to effective uid + * as well. + */ + setuid(getuid()); + setgid(getgid()); +#endif /* SAVED_IDS_WORK_WITH_SETEUID */ + if (setgroups(saved_egroupslen, saved_egroups) < 0) fatal("setgroups: %.100s", strerror(errno)); - if (setegid(saved_egid) < 0) - fatal("setegid %u: %.100s", (u_int) saved_egid, strerror(errno)); temporarily_use_uid_effective = 0; } |