Do not raise in switch root if paths are too long

If we encounter the (unlikely) situation where the combined path to the
new root and a path to a mount to be moved together exceed maximum path length,
we shouldn't crash, but fail this path instead.
This commit is contained in:
Zbigniew Jędrzejewski-Szmek 2016-11-02 22:05:06 -04:00
parent 75ead2b753
commit a6eccc3647

View file

@ -75,17 +75,29 @@ int switch_root(const char *new_root, const char *oldroot, bool detach_oldroot,
NULSTR_FOREACH(i, move_mounts) {
char new_mount[PATH_MAX];
struct stat sb;
size_t n;
xsprintf(new_mount, "%s%s", new_root, i);
n = snprintf(new_mount, sizeof new_mount, "%s%s", new_root, i);
if (n >= sizeof new_mount) {
bool move = mountflags & MS_MOVE;
log_warning("New path is too long, %s: %s%s",
move ? "forcing unmount instead" : "ignoring",
new_root, i);
if (move)
if (umount2(i, MNT_FORCE) < 0)
log_warning_errno(errno, "Failed to unmount %s: %m", i);
continue;
}
mkdir_p_label(new_mount, 0755);
if ((stat(new_mount, &sb) < 0) ||
if (stat(new_mount, &sb) < 0 ||
sb.st_dev != new_root_stat.st_dev) {
/* Mount point seems to be mounted already or
* stat failed. Unmount the old mount
* point. */
* stat failed. Unmount the old mount point. */
if (umount2(i, MNT_DETACH) < 0)
log_warning_errno(errno, "Failed to unmount %s: %m", i);
continue;
@ -97,10 +109,9 @@ int switch_root(const char *new_root, const char *oldroot, bool detach_oldroot,
if (umount2(i, MNT_FORCE) < 0)
log_warning_errno(errno, "Failed to unmount %s: %m", i);
}
if (mountflags & MS_BIND)
log_error_errno(errno, "Failed to bind mount %s to %s: %m", i, new_mount);
} else if (mountflags & MS_BIND)
log_error_errno(errno, "Failed to bind mount %s to %s: %m", i, new_mount);
}
}