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Added native utilities to mount/umount/chroot via capabilities(7).

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Three new helpers will now be installed into ${libexecdir}:
 - xbps-src-capchroot needs to have set CAP_SYS_CHROOT ep.
 - xbps-src-chroot-cap{,u}mount: needs to have set CAP_SYS_ADMIN ep.

That means that libcap and setcap(8) are now required to install
xbps-src and use it as normal user.

--HG--
extra : convert_revision : 586d6526079e085f86bf3e393459d429f6f0ef99
This commit is contained in:
Juan RP 2010-04-26 14:15:49 +02:00
parent 6673252679
commit e3dc3e3066
9 changed files with 293 additions and 34 deletions
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78
xbps-src/libexec/mount.c Normal file
View file

@ -0,0 +1,78 @@
/*
* Bind mounts a filesystem mountpoint into the target directory,
* by using the CAP_SYS_ADMIN capability set on the file.
*
* Juan RP - 2010/04/26 - Public Domain.
*/
#include <stdio.h>
#include <stdlib.h>
#include <stdbool.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/mount.h>
#include <sys/capability.h>
void
usage(void)
{
fprintf(stderr, "Usage: xbps-src-capbmount [-w] <orig> <dest>\n");
exit(EXIT_FAILURE);
}
int
main(int argc, char **argv)
{
cap_t cap;
cap_flag_value_t effective, permitted;
unsigned long flags;
int c, rv;
bool dowrite = false;
while ((c = getopt(argc, argv, "w")) != -1) {
switch (c) {
case 'w':
dowrite = true;
break;
default:
usage();
}
}
argc -= optind;
argv += optind;
if (argc != 2)
usage();
cap = cap_get_proc();
if (cap == NULL) {
fprintf(stderr, "cap_get_proc() returned %s!\n",
strerror(errno));
exit(EXIT_FAILURE);
}
cap_get_flag(cap, CAP_SYS_ADMIN, CAP_EFFECTIVE, &effective);
cap_get_flag(cap, CAP_SYS_ADMIN, CAP_PERMITTED, &permitted);
if ((effective != CAP_SET) && (permitted != CAP_SET)) {
fprintf(stderr, "E: missing 'cap_sys_admin' capability!\n"
"Please set it with: setcap cap_sys_admin=ep %s'\n",
argv[0]);
cap_free(cap);
exit(EXIT_FAILURE);
}
cap_free(cap);
flags = MS_BIND;
if (!dowrite)
flags |= MS_RDONLY;
rv = mount(argv[0], argv[1], "none", flags, NULL);
if (rv != 0) {
fprintf(stderr, "E: cannot mount %s into %s: %s\n", argv[0],
argv[1], strerror(errno));
exit(EXIT_FAILURE);
}
exit(EXIT_SUCCESS);
}