-/* $OpenBSD: file.c,v 1.65 2017/11/30 11:10:07 bentley Exp $ */
+/* $OpenBSD: file.c,v 1.66 2018/01/15 19:45:51 brynet Exp $ */
/*
* Copyright (c) 2015 Nicholas Marriott <nicm@openbsd.org>
*/
#include <sys/types.h>
+#include <sys/ioctl.h>
#include <sys/mman.h>
+#include <sys/queue.h>
+#include <sys/socket.h>
#include <sys/stat.h>
+#include <sys/uio.h>
+#include <sys/wait.h>
#include <err.h>
#include <errno.h>
#include <fcntl.h>
#include <getopt.h>
+#include <imsg.h>
#include <libgen.h>
#include <limits.h>
#include <pwd.h>
#include "magic.h"
#include "xmalloc.h"
-struct input_file {
- struct magic *m;
+struct input_msg {
+ int idx;
- const char *path;
- struct stat sb;
- int fd;
- int error;
+ struct stat sb;
+ int error;
- char link_path[PATH_MAX];
- int link_error;
- int link_target;
+ char link_path[PATH_MAX];
+ int link_error;
+ int link_target;
+};
- void *base;
- size_t size;
- int mapped;
- char *result;
+struct input_ack {
+ int idx;
+};
+
+struct input_file {
+ struct magic *m;
+ struct input_msg *msg;
+
+ const char *path;
+ int fd;
+
+ void *base;
+ size_t size;
+ int mapped;
+ char *result;
};
extern char *__progname;
__dead void usage(void);
-static void prepare_input(struct input_file *, const char *);
+static int prepare_message(struct input_msg *, int, const char *);
+static void send_message(struct imsgbuf *, void *, size_t, int);
+static int read_message(struct imsgbuf *, struct imsg *, pid_t);
+
+static void read_link(struct input_msg *, const char *);
-static void read_link(struct input_file *, const char *);
+static __dead void child(int, pid_t, int, char **);
static void test_file(struct input_file *, size_t);
static int sflag;
static int Wflag;
+static char *magicpath;
+static FILE *magicfp;
+
static struct option longopts[] = {
{ "brief", no_argument, NULL, 'b' },
{ "dereference", no_argument, NULL, 'L' },
int
main(int argc, char **argv)
{
- int opt, idx;
- char *home, *magicpath;
+ int opt, pair[2], fd, idx;
+ char *home;
struct passwd *pw;
- FILE *magicfp = NULL;
- struct magic *m;
- struct input_file *inf = NULL;
- size_t len, width = 0;
+ struct imsgbuf ibuf;
+ struct imsg imsg;
+ struct input_msg msg;
+ struct input_ack *ack;
+ pid_t pid, parent;
- if (pledge("stdio rpath getpw id", NULL) == -1)
- err(1, "pledge");
+ tzset();
for (;;) {
opt = getopt_long(argc, argv, "bchiLsW", longopts, NULL);
} else if (argc == 0)
usage();
+ magicfp = NULL;
if (geteuid() != 0 && !issetugid()) {
home = getenv("HOME");
if (home == NULL || *home == '\0') {
if (magicfp == NULL)
err(1, "%s", magicpath);
- if (!cflag) {
- inf = xcalloc(argc, sizeof *inf);
- for (idx = 0; idx < argc; idx++) {
- len = strlen(argv[idx]) + 1;
- if (len > width)
- width = len;
- prepare_input(&inf[idx], argv[idx]);
- }
+ parent = getpid();
+ if (socketpair(AF_UNIX, SOCK_STREAM, PF_UNSPEC, pair) != 0)
+ err(1, "socketpair");
+ switch (pid = fork()) {
+ case -1:
+ err(1, "fork");
+ case 0:
+ close(pair[0]);
+ child(pair[1], parent, argc, argv);
}
+ close(pair[1]);
- tzset();
+ fclose(magicfp);
+ magicfp = NULL;
- if (pledge("stdio getpw id", NULL) == -1)
- err(1, "pledge");
+ if (cflag)
+ goto wait_for_child;
- if (geteuid() == 0) {
- pw = getpwnam(FILE_USER);
- if (pw == NULL)
- errx(1, "unknown user %s", FILE_USER);
- if (setgroups(1, &pw->pw_gid) != 0)
- err(1, "setgroups");
- if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0)
- err(1, "setresgid");
- if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0)
- err(1, "setresuid");
- }
-
- if (pledge("stdio", NULL) == -1)
- err(1, "pledge");
+ imsg_init(&ibuf, pair[0]);
+ for (idx = 0; idx < argc; idx++) {
+ fd = prepare_message(&msg, idx, argv[idx]);
+ send_message(&ibuf, &msg, sizeof msg, fd);
- m = magic_load(magicfp, magicpath, cflag || Wflag);
- if (cflag) {
- magic_dump(m);
- exit(0);
+ if (read_message(&ibuf, &imsg, pid) == 0)
+ break;
+ if (imsg.hdr.len != IMSG_HEADER_SIZE + sizeof *ack)
+ errx(1, "message too small");
+ ack = imsg.data;
+ if (ack->idx != idx)
+ errx(1, "index not expected");
+ imsg_free(&imsg);
}
- fclose(magicfp);
- for (idx = 0; idx < argc; idx++) {
- inf[idx].m = m;
- test_file(&inf[idx], width);
- if (inf[idx].fd != -1 && inf[idx].fd != STDIN_FILENO)
- close(inf[idx].fd);
+wait_for_child:
+ close(pair[0]);
+ while (wait(NULL) == -1 && errno != ECHILD) {
+ if (errno != EINTR)
+ err(1, "wait");
}
- exit(0);
+ _exit(0); /* let the child flush */
}
-static void
-prepare_input(struct input_file *inf, const char *path)
+static int
+prepare_message(struct input_msg *msg, int idx, const char *path)
{
int fd, mode, error;
- inf->path = path;
+ memset(msg, 0, sizeof *msg);
+ msg->idx = idx;
if (strcmp(path, "-") == 0) {
- if (fstat(STDIN_FILENO, &inf->sb) == -1) {
- inf->error = errno;
- inf->fd = -1;
- return;
+ if (fstat(STDIN_FILENO, &msg->sb) == -1) {
+ msg->error = errno;
+ return (-1);
}
- inf->fd = STDIN_FILENO;
- return;
+ return (STDIN_FILENO);
}
if (Lflag)
- error = stat(path, &inf->sb);
+ error = stat(path, &msg->sb);
else
- error = lstat(path, &inf->sb);
+ error = lstat(path, &msg->sb);
if (error == -1) {
- inf->error = errno;
- inf->fd = -1;
- return;
+ msg->error = errno;
+ return (-1);
}
- /* We don't need them, so don't open directories or symlinks. */
- mode = inf->sb.st_mode;
+ /*
+ * pledge(2) doesn't let us pass directory file descriptors around -
+ * but in fact we don't need them, so just don't open directories or
+ * symlinks (which could be to directories).
+ */
+ mode = msg->sb.st_mode;
if (!S_ISDIR(mode) && !S_ISLNK(mode)) {
fd = open(path, O_RDONLY|O_NONBLOCK);
if (fd == -1 && (errno == ENFILE || errno == EMFILE))
} else
fd = -1;
if (S_ISLNK(mode))
- read_link(inf, path);
- inf->fd = fd;
+ read_link(msg, path);
+ return (fd);
+
+}
+
+static void
+send_message(struct imsgbuf *ibuf, void *msg, size_t msglen, int fd)
+{
+ if (imsg_compose(ibuf, -1, -1, 0, fd, msg, msglen) != 1)
+ err(1, "imsg_compose");
+ if (imsg_flush(ibuf) != 0)
+ err(1, "imsg_flush");
+}
+
+static int
+read_message(struct imsgbuf *ibuf, struct imsg *imsg, pid_t from)
+{
+ int n;
+
+ while ((n = imsg_read(ibuf)) == -1 && errno == EAGAIN)
+ /* nothing */ ;
+ if (n == -1)
+ err(1, "imsg_read");
+ if (n == 0)
+ return (0);
+
+ if ((n = imsg_get(ibuf, imsg)) == -1)
+ err(1, "imsg_get");
+ if (n == 0)
+ return (0);
+
+ if ((pid_t)imsg->hdr.pid != from)
+ errx(1, "PIDs don't match");
+
+ return (n);
+
}
static void
-read_link(struct input_file *inf, const char *path)
+read_link(struct input_msg *msg, const char *path)
{
struct stat sb;
char lpath[PATH_MAX];
size = readlink(path, lpath, sizeof lpath - 1);
if (size == -1) {
- inf->link_error = errno;
+ msg->link_error = errno;
return;
}
lpath[size] = '\0';
if (*lpath == '/')
- strlcpy(inf->link_path, lpath, sizeof inf->link_path);
+ strlcpy(msg->link_path, lpath, sizeof msg->link_path);
else {
copy = xstrdup(path);
root = dirname(copy);
if (*root == '\0' || strcmp(root, ".") == 0 ||
strcmp (root, "/") == 0)
- strlcpy(inf->link_path, lpath, sizeof inf->link_path);
+ strlcpy(msg->link_path, lpath, sizeof msg->link_path);
else {
- used = snprintf(inf->link_path, sizeof inf->link_path,
+ used = snprintf(msg->link_path, sizeof msg->link_path,
"%s/%s", root, lpath);
- if (used < 0 || (size_t)used >= sizeof inf->link_path) {
- inf->link_error = ENAMETOOLONG;
+ if (used < 0 || (size_t)used >= sizeof msg->link_path) {
+ msg->link_error = ENAMETOOLONG;
free(copy);
return;
}
}
if (!Lflag && stat(path, &sb) == -1)
- inf->link_target = errno;
+ msg->link_target = errno;
+}
+
+static __dead void
+child(int fd, pid_t parent, int argc, char **argv)
+{
+ struct passwd *pw;
+ struct magic *m;
+ struct imsgbuf ibuf;
+ struct imsg imsg;
+ struct input_msg *msg;
+ struct input_ack ack;
+ struct input_file inf;
+ int i, idx;
+ size_t len, width = 0;
+
+ if (pledge("stdio getpw recvfd id", NULL) == -1)
+ err(1, "pledge");
+
+ if (geteuid() == 0) {
+ pw = getpwnam(FILE_USER);
+ if (pw == NULL)
+ errx(1, "unknown user %s", FILE_USER);
+ if (setgroups(1, &pw->pw_gid) != 0)
+ err(1, "setgroups");
+ if (setresgid(pw->pw_gid, pw->pw_gid, pw->pw_gid) != 0)
+ err(1, "setresgid");
+ if (setresuid(pw->pw_uid, pw->pw_uid, pw->pw_uid) != 0)
+ err(1, "setresuid");
+ }
+
+ if (pledge("stdio recvfd", NULL) == -1)
+ err(1, "pledge");
+
+ m = magic_load(magicfp, magicpath, cflag || Wflag);
+ if (cflag) {
+ magic_dump(m);
+ exit(0);
+ }
+
+ for (i = 0; i < argc; i++) {
+ len = strlen(argv[i]) + 1;
+ if (len > width)
+ width = len;
+ }
+
+ imsg_init(&ibuf, fd);
+ for (;;) {
+ if (read_message(&ibuf, &imsg, parent) == 0)
+ break;
+ if (imsg.hdr.len != IMSG_HEADER_SIZE + sizeof *msg)
+ errx(1, "message too small");
+ msg = imsg.data;
+
+ idx = msg->idx;
+ if (idx < 0 || idx >= argc)
+ errx(1, "index out of range");
+
+ memset(&inf, 0, sizeof inf);
+ inf.m = m;
+ inf.msg = msg;
+
+ inf.path = argv[idx];
+ inf.fd = imsg.fd;
+
+ test_file(&inf, width);
+
+ if (imsg.fd != -1)
+ close(imsg.fd);
+ imsg_free(&imsg);
+
+ ack.idx = idx;
+ send_message(&ibuf, &ack, sizeof ack, -1);
+ }
+ exit(0);
}
static void *
{
size_t used;
- if (inf->sb.st_size == 0 && S_ISREG(inf->sb.st_mode))
+ if (inf->msg->sb.st_size == 0 && S_ISREG(inf->msg->sb.st_mode))
return (0); /* empty file */
- if (inf->sb.st_size == 0 || inf->sb.st_size > FILE_READ_SIZE)
+ if (inf->msg->sb.st_size == 0 || inf->msg->sb.st_size > FILE_READ_SIZE)
inf->size = FILE_READ_SIZE;
else
- inf->size = inf->sb.st_size;
+ inf->size = inf->msg->sb.st_size;
- if (!S_ISREG(inf->sb.st_mode))
+ if (!S_ISREG(inf->msg->sb.st_mode))
goto try_read;
inf->base = mmap(NULL, inf->size, PROT_READ, MAP_PRIVATE, inf->fd, 0);
static int
try_stat(struct input_file *inf)
{
- if (inf->error != 0) {
+ if (inf->msg->error != 0) {
xasprintf(&inf->result, "cannot stat '%s' (%s)", inf->path,
- strerror(inf->error));
+ strerror(inf->msg->error));
return (1);
}
if (sflag || strcmp(inf->path, "-") == 0) {
- switch (inf->sb.st_mode & S_IFMT) {
+ switch (inf->msg->sb.st_mode & S_IFMT) {
case S_IFIFO:
if (strcmp(inf->path, "-") != 0)
break;
}
}
- if (iflag && (inf->sb.st_mode & S_IFMT) != S_IFREG) {
+ if (iflag && (inf->msg->sb.st_mode & S_IFMT) != S_IFREG) {
xasprintf(&inf->result, "application/x-not-regular-file");
return (1);
}
- switch (inf->sb.st_mode & S_IFMT) {
+ switch (inf->msg->sb.st_mode & S_IFMT) {
case S_IFDIR:
xasprintf(&inf->result, "directory");
return (1);
case S_IFLNK:
- if (inf->link_error != 0) {
+ if (inf->msg->link_error != 0) {
xasprintf(&inf->result, "unreadable symlink '%s' (%s)",
- inf->path, strerror(inf->link_error));
+ inf->path, strerror(inf->msg->link_error));
return (1);
}
- if (inf->link_target == ELOOP)
+ if (inf->msg->link_target == ELOOP)
xasprintf(&inf->result, "symbolic link in a loop");
- else if (inf->link_target != 0) {
+ else if (inf->msg->link_target != 0) {
xasprintf(&inf->result, "broken symbolic link to '%s'",
- inf->link_path);
+ inf->msg->link_path);
} else {
xasprintf(&inf->result, "symbolic link to '%s'",
- inf->link_path);
+ inf->msg->link_path);
}
return (1);
case S_IFSOCK:
return (1);
case S_IFBLK:
xasprintf(&inf->result, "block special (%ld/%ld)",
- (long)major(inf->sb.st_rdev),
- (long)minor(inf->sb.st_rdev));
+ (long)major(inf->msg->sb.st_rdev),
+ (long)minor(inf->msg->sb.st_rdev));
return (1);
case S_IFCHR:
xasprintf(&inf->result, "character special (%ld/%ld)",
- (long)major(inf->sb.st_rdev),
- (long)minor(inf->sb.st_rdev));
+ (long)major(inf->msg->sb.st_rdev),
+ (long)minor(inf->msg->sb.st_rdev));
return (1);
case S_IFIFO:
xasprintf(&inf->result, "fifo (named pipe)");
{
char tmp[256] = "";
- if (inf->sb.st_size == 0 && S_ISREG(inf->sb.st_mode))
+ if (inf->msg->sb.st_size == 0 && S_ISREG(inf->msg->sb.st_mode))
return (0); /* empty file */
if (inf->fd != -1)
return (0);
- if (inf->sb.st_mode & (S_IWUSR|S_IWGRP|S_IWOTH))
+ if (inf->msg->sb.st_mode & (S_IWUSR|S_IWGRP|S_IWOTH))
strlcat(tmp, "writable, ", sizeof tmp);
- if (inf->sb.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH))
+ if (inf->msg->sb.st_mode & (S_IXUSR|S_IXGRP|S_IXOTH))
strlcat(tmp, "executable, ", sizeof tmp);
- if (S_ISREG(inf->sb.st_mode))
+ if (S_ISREG(inf->msg->sb.st_mode))
strlcat(tmp, "regular file, ", sizeof tmp);
strlcat(tmp, "no read permission", sizeof tmp);
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