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v1.9.14
src/ttyname.c
401 строка
11 KB
Todd C. Miller
Avoid calling isatty()/ttyname() on std{in,out,err} if not a char dev.
18 апр 2023, 22:52
18 апр 2023, 22:52
ab0f8dd
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/* * SPDX-License-Identifier: ISC * * Copyright (c) 2012-2022 Todd C. Miller <Todd.Miller@sudo.ws> * * Permission to use, copy, modify, and distribute this software for any * purpose with or without fee is hereby granted, provided that the above * copyright notice and this permission notice appear in all copies. * * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN * ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF * OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE. */ /* * This is an open source non-commercial project. Dear PVS-Studio, please check it. * PVS-Studio Static Code Analyzer for C, C++ and C#: http://www.viva64.com */ #include <config.h> /* Large files not supported by procfs.h on Solaris. */ #if defined(HAVE_STRUCT_PSINFO_PR_TTYDEV) # undef _FILE_OFFSET_BITS # undef _LARGE_FILES #endif #include <sys/types.h> #include <sys/stat.h> #if defined(MAJOR_IN_MKDEV) # include <sys/mkdev.h> #elif defined(MAJOR_IN_SYSMACROS) # include <sys/sysmacros.h> #endif #include <stdio.h> #include <stdlib.h> #include <string.h> #include <unistd.h> #include <errno.h> #include <fcntl.h> #include <limits.h> #include <dirent.h> #if defined(HAVE_KINFO_PROC2_NETBSD) || defined (HAVE_KINFO_PROC_OPENBSD) || defined(HAVE_KINFO_PROC_44BSD) # include <sys/sysctl.h> #elif defined(HAVE_KINFO_PROC_FREEBSD) || defined(HAVE_KINFO_PROC_DFLY) # include <sys/param.h> # include <sys/sysctl.h> # include <sys/user.h> #endif #if defined(HAVE_PROCFS_H) # include <procfs.h> #elif defined(HAVE_SYS_PROCFS_H) # include <sys/procfs.h> #endif #ifdef HAVE_PSTAT_GETPROC # include <sys/pstat.h> #endif #include "sudo.h" /* * How to access the tty device number in struct kinfo_proc. */ #if defined(HAVE_KINFO_PROC2_NETBSD) # define SUDO_KERN_PROC KERN_PROC2 # define sudo_kinfo_proc kinfo_proc2 # define sudo_kp_tdev p_tdev # define sudo_kp_namelen 6 #elif defined(HAVE_KINFO_PROC_OPENBSD) # define SUDO_KERN_PROC KERN_PROC # define sudo_kinfo_proc kinfo_proc # define sudo_kp_tdev p_tdev # define sudo_kp_namelen 6 #elif defined(HAVE_KINFO_PROC_FREEBSD) # define SUDO_KERN_PROC KERN_PROC # define sudo_kinfo_proc kinfo_proc # define sudo_kp_tdev ki_tdev # define sudo_kp_namelen 4 #elif defined(HAVE_KINFO_PROC_DFLY) # define SUDO_KERN_PROC KERN_PROC # define sudo_kinfo_proc kinfo_proc # define sudo_kp_tdev kp_tdev # define sudo_kp_namelen 4 #elif defined(HAVE_KINFO_PROC_44BSD) # define SUDO_KERN_PROC KERN_PROC # define sudo_kinfo_proc kinfo_proc # define sudo_kp_tdev kp_eproc.e_tdev # define sudo_kp_namelen 4 #endif #if defined(sudo_kp_tdev) /* * Store the name of the tty to which the process is attached in name. * Returns name on success and NULL on failure, setting errno. */ char * get_process_ttyname(char *name, size_t namelen) { struct sudo_kinfo_proc *ki_proc = NULL; size_t size = sizeof(*ki_proc); int mib[6], rc, serrno = errno; char *ret = NULL; debug_decl(get_process_ttyname, SUDO_DEBUG_UTIL); /* * Lookup controlling tty for this process via sysctl. * This will work even if std{in,out,err} are redirected. */ mib[0] = CTL_KERN; mib[1] = SUDO_KERN_PROC; mib[2] = KERN_PROC_PID; mib[3] = (int)getpid(); mib[4] = sizeof(*ki_proc); mib[5] = 1; for (;;) { struct sudo_kinfo_proc *kp; size += size / 10; if ((kp = realloc(ki_proc, size)) == NULL) { rc = -1; break; /* really out of memory. */ } ki_proc = kp; rc = sysctl(mib, sudo_kp_namelen, ki_proc, &size, NULL, 0); if (rc != -1 || errno != ENOMEM) break; } errno = ENOENT; if (rc != -1) { if ((dev_t)ki_proc->sudo_kp_tdev != (dev_t)-1) { errno = serrno; ret = sudo_ttyname_dev(ki_proc->sudo_kp_tdev, name, namelen); if (ret == NULL) { sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO, "unable to map device number %lu to name", (unsigned long)ki_proc->sudo_kp_tdev); } } } else { sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO, "unable to resolve tty via KERN_PROC"); } free(ki_proc); debug_return_str(ret); } #elif defined(HAVE_STRUCT_PSINFO_PR_TTYDEV) /* * Store the name of the tty to which the process is attached in name. * Returns name on success and NULL on failure, setting errno. */ char * get_process_ttyname(char *name, size_t namelen) { char path[PATH_MAX], *ret = NULL; struct psinfo psinfo; ssize_t nread; int fd, serrno = errno; debug_decl(get_process_ttyname, SUDO_DEBUG_UTIL); /* Try to determine the tty from pr_ttydev in /proc/pid/psinfo. */ (void)snprintf(path, sizeof(path), "/proc/%u/psinfo", (unsigned int)getpid()); if ((fd = open(path, O_RDONLY, 0)) != -1) { nread = read(fd, &psinfo, sizeof(psinfo)); close(fd); if (nread == (ssize_t)sizeof(psinfo)) { dev_t rdev = (dev_t)psinfo.pr_ttydev; #if defined(_AIX) && defined(DEVNO64) if ((psinfo.pr_ttydev & DEVNO64) && sizeof(dev_t) == 4) rdev = makedev(major64(psinfo.pr_ttydev), minor64(psinfo.pr_ttydev)); #endif if (rdev != (dev_t)-1) { errno = serrno; ret = sudo_ttyname_dev(rdev, name, namelen); goto done; } } } else { struct stat sb; int i; /* Missing /proc/pid/psinfo file. */ for (i = STDIN_FILENO; i <= STDERR_FILENO; i++) { if (sudo_isatty(i, &sb)) { ret = sudo_ttyname_dev(sb.st_rdev, name, namelen); goto done; } } } errno = ENOENT; done: if (ret == NULL) sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO, "unable to resolve tty via %s", path); debug_return_str(ret); } #elif defined(__linux__) /* * Store the name of the tty to which the process is attached in name. * Returns name on success and NULL on failure, setting errno. */ char * get_process_ttyname(char *name, size_t namelen) { const char path[] = "/proc/self/stat"; char *cp, buf[1024]; char *ret = NULL; int serrno = errno; pid_t ppid = 0; ssize_t nread; int fd; debug_decl(get_process_ttyname, SUDO_DEBUG_UTIL); /* * Try to determine the tty from tty_nr in /proc/self/stat. * Ignore /proc/self/stat if it contains embedded NUL bytes. */ if ((fd = open(path, O_RDONLY | O_NOFOLLOW)) != -1) { cp = buf; while ((nread = read(fd, cp, buf + sizeof(buf) - cp)) != 0) { if (nread == -1) { if (errno == EAGAIN || errno == EINTR) continue; break; } cp += nread; if (cp >= buf + sizeof(buf)) break; } if (nread == 0 && memchr(buf, '\0', cp - buf) == NULL) { /* * Field 7 is the tty dev (0 if no tty). * Since the process name at field 2 "(comm)" may include * whitespace (including newlines), start at the last ')' found. */ *cp = '\0'; cp = strrchr(buf, ')'); if (cp != NULL) { char *ep = cp; const char *errstr; int field = 1; while (*++ep != '\0') { if (*ep == ' ') { *ep = '\0'; field++; if (field == 7) { int tty_nr = sudo_strtonum(cp, INT_MIN, INT_MAX, &errstr); if (errstr) { sudo_debug_printf(SUDO_DEBUG_ERROR|SUDO_DEBUG_LINENO, "%s: tty device %s: %s", path, cp, errstr); } if (tty_nr != 0) { /* * Avoid sign extension when assigning tdev. * tty_nr in /proc/self/stat is printed as a * signed int but the actual device number is an * unsigned int and dev_t is unsigned long long. */ dev_t tdev = (unsigned int)tty_nr; errno = serrno; ret = sudo_ttyname_dev(tdev, name, namelen); goto done; } break; } if (field == 3) { ppid = sudo_strtonum(cp, INT_MIN, INT_MAX, NULL); } cp = ep + 1; } } } } } if (ppid == 0) { struct stat sb; int i; /* No parent pid found, /proc/self/stat is missing or corrupt. */ for (i = STDIN_FILENO; i <= STDERR_FILENO; i++) { if (sudo_isatty(i, &sb)) { ret = sudo_ttyname_dev(sb.st_rdev, name, namelen); goto done; } } } errno = ENOENT; done: if (fd != -1) close(fd); if (ret == NULL) sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO, "unable to resolve tty via %s", path); debug_return_str(ret); } #elif defined(HAVE_PSTAT_GETPROC) /* * Store the name of the tty to which the process is attached in name. * Returns name on success and NULL on failure, setting errno. */ char * get_process_ttyname(char *name, size_t namelen) { struct pst_status pst; char *ret = NULL; int rc, serrno = errno; debug_decl(get_process_ttyname, SUDO_DEBUG_UTIL); /* * Determine the tty from psdev in struct pst_status. * EOVERFLOW is not a fatal error for the fields we use. * See the "EOVERFLOW Error" section of pstat_getvminfo(3). */ rc = pstat_getproc(&pst, sizeof(pst), 0, getpid()); if (rc != -1 || errno == EOVERFLOW) { if (pst.pst_term.psd_major != -1 && pst.pst_term.psd_minor != -1) { errno = serrno; ret = sudo_ttyname_dev(makedev(pst.pst_term.psd_major, pst.pst_term.psd_minor), name, namelen); goto done; } } errno = ENOENT; done: if (ret == NULL) sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO, "unable to resolve tty via pstat"); debug_return_str(ret); } #else /* * Store the name of the tty to which the process is attached in name. * Returns name on success and NULL on failure, setting errno. */ char * get_process_ttyname(char *name, size_t namelen) { struct stat sb; char *tty; int i; debug_decl(get_process_ttyname, SUDO_DEBUG_UTIL); for (i = STDIN_FILENO; i <= STDERR_FILENO; i++) { /* Only call ttyname() on a character special device. */ if (fstat(i, &sb) == -1 || !S_ISCHR(sb.st_mode)) continue; if ((tty = ttyname(i)) == NULL) continue; if (strlcpy(name, tty, namelen) >= namelen) { errno = ENAMETOOLONG; sudo_debug_printf( SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO, "unable to store tty from ttyname"); debug_return_str(NULL); } debug_return_str(name); } sudo_debug_printf(SUDO_DEBUG_WARN|SUDO_DEBUG_LINENO|SUDO_DEBUG_ERRNO, "unable to resolve tty via ttyname"); errno = ENOENT; debug_return_str(NULL); } #endif /* * Like isatty(3) but stats the fd and stores the result in sb. * Only calls isatty(3) if fd is a character special device. * Returns true if a tty, else returns false and sets errno. */ bool sudo_isatty(int fd, struct stat *sb) { bool ret = false; debug_decl(sudo_isatty, SUDO_DEBUG_EXEC); if (fstat(fd, sb) == 0) { if (!S_ISCHR(sb->st_mode)) { errno = ENOTTY; } else { ret = isatty(fd) == 1; } } else { /* Always initialize sb. */ memset(sb, 0, sizeof(*sb)); } debug_return_bool(ret); }