From 97c26c1924b076ef23ebe4381558e8aa025712b2 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 16:54:37 +0200 Subject: Adding upstream version 1:4.13+dfsg1. Signed-off-by: Daniel Baumann --- libmisc/user_busy.c | 273 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 273 insertions(+) create mode 100644 libmisc/user_busy.c (limited to 'libmisc/user_busy.c') diff --git a/libmisc/user_busy.c b/libmisc/user_busy.c new file mode 100644 index 0000000..c03feb2 --- /dev/null +++ b/libmisc/user_busy.c @@ -0,0 +1,273 @@ +/* + * SPDX-FileCopyrightText: 1991 - 1994, Julianne Frances Haugh + * SPDX-FileCopyrightText: 1996 - 2000, Marek Michałkiewicz + * SPDX-FileCopyrightText: 2000 - 2006, Tomasz Kłoczko + * SPDX-FileCopyrightText: 2007 - 2009, Nicolas François + * + * SPDX-License-Identifier: BSD-3-Clause + */ + +#include + +#ident "$Id: $" + +#include +#include +#include +#include +#include +#include +#include "defines.h" +#include "prototypes.h" +#ifdef ENABLE_SUBIDS +#include "subordinateio.h" +#endif /* ENABLE_SUBIDS */ +#include "shadowlog.h" + +#ifdef __linux__ +static int check_status (const char *name, const char *sname, uid_t uid); +static int user_busy_processes (const char *name, uid_t uid); +#else /* !__linux__ */ +static int user_busy_utmp (const char *name); +#endif /* !__linux__ */ + +/* + * user_busy - check if an user if currently running processes + */ +int user_busy (const char *name, uid_t uid) +{ + /* There are no standard ways to get the list of processes. + * An option could be to run an external tool (ps). + */ +#ifdef __linux__ + /* On Linux, directly parse /proc */ + return user_busy_processes (name, uid); +#else /* !__linux__ */ + /* If we cannot rely on /proc, check is there is a record in utmp + * indicating that the user is still logged in */ + return user_busy_utmp (name); +#endif /* !__linux__ */ +} + +#ifndef __linux__ +static int user_busy_utmp (const char *name) +{ +#ifdef USE_UTMPX + struct utmpx *utent; + + setutxent (); + while ((utent = getutxent ()) != NULL) +#else /* !USE_UTMPX */ + struct utmp *utent; + + setutent (); + while ((utent = getutent ()) != NULL) +#endif /* !USE_UTMPX */ + { + if (utent->ut_type != USER_PROCESS) { + continue; + } + if (strncmp (utent->ut_user, name, sizeof utent->ut_user) != 0) { + continue; + } + if (kill (utent->ut_pid, 0) != 0) { + continue; + } + + fprintf (log_get_logfd(), + _("%s: user %s is currently logged in\n"), + log_get_progname(), name); + return 1; + } + + return 0; +} +#endif /* !__linux__ */ + +#ifdef __linux__ +#ifdef ENABLE_SUBIDS +#define in_parentuid_range(uid) ((uid) >= parentuid && (uid) < parentuid + range) +static int different_namespace (const char *sname) +{ + /* 41: /proc/xxxxxxxxxx/task/xxxxxxxxxx/ns/user + \0 */ + char path[41]; + char buf[512], buf2[512]; + ssize_t llen1, llen2; + + snprintf (path, 41, "/proc/%s/ns/user", sname); + + if ((llen1 = readlink (path, buf, sizeof(buf))) == -1) + return 0; + + if ((llen2 = readlink ("/proc/self/ns/user", buf2, sizeof(buf2))) == -1) + return 0; + + if (llen1 == llen2 && memcmp (buf, buf2, llen1) == 0) + return 0; /* same namespace */ + + return 1; +} +#endif /* ENABLE_SUBIDS */ + + +static int check_status (const char *name, const char *sname, uid_t uid) +{ + /* 40: /proc/xxxxxxxxxx/task/xxxxxxxxxx/status + \0 */ + char status[40]; + char line[1024]; + FILE *sfile; + + snprintf (status, 40, "/proc/%s/status", sname); + + sfile = fopen (status, "r"); + if (NULL == sfile) { + return 0; + } + while (fgets (line, sizeof (line), sfile) == line) { + if (strncmp (line, "Uid:\t", 5) == 0) { + unsigned long ruid, euid, suid; + + assert (uid == (unsigned long) uid); + (void) fclose (sfile); + if (sscanf (line, + "Uid:\t%lu\t%lu\t%lu\n", + &ruid, &euid, &suid) == 3) { + if ( (ruid == (unsigned long) uid) + || (euid == (unsigned long) uid) + || (suid == (unsigned long) uid) ) { + return 1; + } +#ifdef ENABLE_SUBIDS + if ( different_namespace (sname) + && ( have_sub_uids(name, ruid, 1) + || have_sub_uids(name, euid, 1) + || have_sub_uids(name, suid, 1)) + ) { + return 1; + } +#endif /* ENABLE_SUBIDS */ + } else { + /* Ignore errors. This is just a best effort. */ + } + return 0; + } + } + (void) fclose (sfile); + return 0; +} + +static int user_busy_processes (const char *name, uid_t uid) +{ + DIR *proc; + struct dirent *ent; + char *tmp_d_name; + pid_t pid; + DIR *task_dir; + /* 22: /proc/xxxxxxxxxx/task + \0 */ + char task_path[22]; + char root_path[22]; + struct stat sbroot; + struct stat sbroot_process; + +#ifdef ENABLE_SUBIDS + sub_uid_open (O_RDONLY); +#endif /* ENABLE_SUBIDS */ + + proc = opendir ("/proc"); + if (proc == NULL) { + perror ("opendir /proc"); +#ifdef ENABLE_SUBIDS + sub_uid_close(); +#endif + return 0; + } + if (stat ("/", &sbroot) != 0) { + perror ("stat (\"/\")"); + (void) closedir (proc); +#ifdef ENABLE_SUBIDS + sub_uid_close(); +#endif + return 0; + } + + while ((ent = readdir (proc)) != NULL) { + tmp_d_name = ent->d_name; + /* + * Ingo Molnar's patch introducing NPTL for 2.4 hides + * threads in the /proc directory by prepending a period. + * This patch is applied by default in some RedHat + * kernels. + */ + if ( (strcmp (tmp_d_name, ".") == 0) + || (strcmp (tmp_d_name, "..") == 0)) { + continue; + } + if (*tmp_d_name == '.') { + tmp_d_name++; + } + + /* Check if this is a valid PID */ + if (get_pid (tmp_d_name, &pid) == 0) { + continue; + } + + /* Check if the process is in our chroot */ + snprintf (root_path, 22, "/proc/%lu/root", (unsigned long) pid); + root_path[21] = '\0'; + if (stat (root_path, &sbroot_process) != 0) { + continue; + } + if ( (sbroot.st_dev != sbroot_process.st_dev) + || (sbroot.st_ino != sbroot_process.st_ino)) { + continue; + } + + if (check_status (name, tmp_d_name, uid) != 0) { + (void) closedir (proc); +#ifdef ENABLE_SUBIDS + sub_uid_close(); +#endif + fprintf (log_get_logfd(), + _("%s: user %s is currently used by process %d\n"), + log_get_progname(), name, pid); + return 1; + } + + snprintf (task_path, 22, "/proc/%lu/task", (unsigned long) pid); + task_path[21] = '\0'; + task_dir = opendir (task_path); + if (task_dir != NULL) { + while ((ent = readdir (task_dir)) != NULL) { + pid_t tid; + if (get_pid (ent->d_name, &tid) == 0) { + continue; + } + if (tid == pid) { + continue; + } + if (check_status (name, task_path+6, uid) != 0) { + (void) closedir (proc); + (void) closedir (task_dir); +#ifdef ENABLE_SUBIDS + sub_uid_close(); +#endif + fprintf (log_get_logfd(), + _("%s: user %s is currently used by process %d\n"), + log_get_progname(), name, pid); + return 1; + } + } + (void) closedir (task_dir); + } else { + /* Ignore errors. This is just a best effort */ + } + } + + (void) closedir (proc); +#ifdef ENABLE_SUBIDS + sub_uid_close(); +#endif /* ENABLE_SUBIDS */ + return 0; +} +#endif /* __linux__ */ + -- cgit v1.2.3