8a9e65f3e5
- CVE-2026-35535 - Privilege escalation due to failure in privilege drop calls Resolves: RHEL-166060
142 lines
4.6 KiB
Diff
142 lines
4.6 KiB
Diff
From 3e474c2f201484be83d994ae10a4e20e8c81bb69 Mon Sep 17 00:00:00 2001
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From: "Todd C. Miller" <Todd.Miller@sudo.ws>
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Date: Sat, 8 Nov 2025 15:34:02 -0700
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Subject: [PATCH] exec_mailer: Set group as well as uid when running the mailer
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Also make a setuid(), setgid() or setgroups() failure fatal.
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Found by the ZeroPath AI Security Engineer <https://zeropath.com>
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Backported to RHEL 8.10 by Alejandro López <allopez@redhat.com> with some
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help of Claude Code.
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---
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diff --git a/include/sudo_eventlog.h b/include/sudo_eventlog.h
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index 07ef9dc..cdf27f0 100644
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--- a/include/sudo_eventlog.h
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+++ b/include/sudo_eventlog.h
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@@ -78,6 +78,7 @@ struct eventlog_config {
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int syslog_maxlen;
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int file_maxlen;
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uid_t mailuid;
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+ gid_t mailgid;
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bool omit_hostname;
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const char *logpath;
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const char *time_fmt;
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@@ -136,7 +137,7 @@ void eventlog_set_syslog_rejectpri(int pri);
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void eventlog_set_syslog_alertpri(int pri);
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void eventlog_set_syslog_maxlen(int len);
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void eventlog_set_file_maxlen(int len);
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-void eventlog_set_mailuid(uid_t uid);
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+void eventlog_set_mailuser(uid_t uid, gid_t gid);
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void eventlog_set_omit_hostname(bool omit_hostname);
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void eventlog_set_logpath(const char *path);
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void eventlog_set_time_fmt(const char *fmt);
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diff --git a/lib/eventlog/eventlog.c b/lib/eventlog/eventlog.c
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index ca8ca96..1ae1176 100644
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--- a/lib/eventlog/eventlog.c
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+++ b/lib/eventlog/eventlog.c
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@@ -280,15 +280,13 @@ exec_mailer(int pipein)
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syslog(LOG_ERR, _("unable to dup stdin: %m")); // -V618
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sudo_debug_printf(SUDO_DEBUG_ERROR,
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"unable to dup stdin: %s", strerror(errno));
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- sudo_debug_exit(__func__, __FILE__, __LINE__, sudo_debug_subsys);
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- _exit(127);
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+ goto bad;
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}
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/* Build up an argv based on the mailer path and flags */
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if ((mflags = strdup(evl_conf->mailerflags)) == NULL) {
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syslog(LOG_ERR, _("unable to allocate memory")); // -V618
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- sudo_debug_exit(__func__, __FILE__, __LINE__, sudo_debug_subsys);
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- _exit(127);
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+ goto bad;
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}
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if ((argv[0] = strrchr(mpath, '/')))
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argv[0]++;
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@@ -310,11 +308,23 @@ exec_mailer(int pipein)
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if (setuid(ROOT_UID) != 0) {
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sudo_debug_printf(SUDO_DEBUG_ERROR, "unable to change uid to %u",
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ROOT_UID);
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+ goto bad;
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+ }
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+ if (setgid(evl_conf->mailgid) != 0) {
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+ sudo_debug_printf(SUDO_DEBUG_ERROR, "unable to change gid to %u",
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+ (unsigned int)evl_conf->mailgid);
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+ goto bad;
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+ }
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+ if (setgroups(1, &evl_conf->mailgid) != 0) {
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+ sudo_debug_printf(SUDO_DEBUG_ERROR, "unable to set groups to %u",
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+ (unsigned int)evl_conf->mailgid);
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+ goto bad;
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}
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if (evl_conf->mailuid != ROOT_UID) {
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if (setuid(evl_conf->mailuid) != 0) {
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sudo_debug_printf(SUDO_DEBUG_ERROR, "unable to change uid to %u",
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(unsigned int)evl_conf->mailuid);
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+ goto bad;
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}
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}
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sudo_debug_exit(__func__, __FILE__, __LINE__, sudo_debug_subsys);
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@@ -326,6 +336,9 @@ exec_mailer(int pipein)
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sudo_debug_printf(SUDO_DEBUG_ERROR, "unable to execute %s: %s",
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mpath, strerror(errno));
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_exit(127);
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+bad:
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+ sudo_debug_exit(__func__, __FILE__, __LINE__, sudo_debug_subsys);
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+ _exit(127);
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}
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/* Send a message to the mailto user */
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diff --git a/lib/eventlog/eventlog_conf.c b/lib/eventlog/eventlog_conf.c
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index 8ad0385..1c1d0a6 100644
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--- a/lib/eventlog/eventlog_conf.c
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+++ b/lib/eventlog/eventlog_conf.c
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@@ -70,6 +70,7 @@ static struct eventlog_config evl_conf = {
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MAXSYSLOGLEN, /* syslog_maxlen */
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0, /* file_maxlen */
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ROOT_UID, /* mailuid */
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+ ROOT_GID, /* mailgid */
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false, /* omit_hostname */
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_PATH_SUDO_LOGFILE, /* logpath */
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"%h %e %T", /* time_fmt */
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@@ -151,9 +152,10 @@ eventlog_set_file_maxlen(int len)
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}
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void
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-eventlog_set_mailuid(uid_t uid)
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+eventlog_set_mailuser(uid_t uid, gid_t gid)
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{
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evl_conf.mailuid = uid;
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+ evl_conf.mailgid = gid;
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}
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void
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diff --git a/plugins/sudoers/logging.c b/plugins/sudoers/logging.c
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index 776f881..6046783 100644
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--- a/plugins/sudoers/logging.c
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+++ b/plugins/sudoers/logging.c
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@@ -788,8 +788,10 @@ init_eventlog_config(void)
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int logtype = 0;
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#ifdef NO_ROOT_MAILER
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uid_t mailuid = user_uid;
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+ gid_t mailgid = user_gid;
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#else
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uid_t mailuid = ROOT_UID;
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+ gid_t mailgid = ROOT_GID;
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#endif
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debug_decl(init_eventlog_config, SUDOERS_DEBUG_LOGGING);
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@@ -805,7 +807,7 @@ init_eventlog_config(void)
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eventlog_set_syslog_alertpri(def_syslog_badpri);
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eventlog_set_syslog_maxlen(def_syslog_maxlen);
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eventlog_set_file_maxlen(def_loglinelen);
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- eventlog_set_mailuid(mailuid);
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+ eventlog_set_mailuser(mailuid, mailgid);
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eventlog_set_omit_hostname(!def_log_host);
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eventlog_set_logpath(def_logfile);
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eventlog_set_time_fmt(def_log_year ? "%h %e %T %Y" : "%h %e %T");
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--
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2.53.0
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