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ostbuild: Also allow making directories read-only

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This commit is contained in:
Colin Walters 2011-12-06 19:36:42 -05:00
parent a4b249e333
commit fb5ecdac42
1 changed files with 100 additions and 27 deletions
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127
src/ostbuild/ostbuild-user-chroot.c
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@ -65,6 +65,32 @@ fatal_errno (const char *message)
exit (1);
}
typedef struct _BindMount BindMount;
struct _BindMount {
const char *source;
const char *dest;
unsigned int readonly;
BindMount *next;
};
static BindMount *
reverse_bind_mount_list (BindMount *mount)
{
BindMount *prev = NULL;
while (mount)
{
BindMount *next = mount->next;
mount->next = prev;
prev = mount;
mount = next;
}
return prev;
}
int
main (int argc,
char **argv)
@ -74,10 +100,12 @@ main (int argc,
const char *program;
uid_t ruid, euid, suid;
gid_t rgid, egid, sgid;
int after_bind_arg_index;
int i;
int after_mount_arg_index;
unsigned int n_mounts = 0;
const unsigned int max_mounts = 50; /* Totally arbitrary... */
char **program_argv;
char **argv_iter;
BindMount *bind_mounts = NULL;
BindMount *bind_mount_iter;
if (argc <= 0)
return 1;
@ -89,22 +117,57 @@ main (int argc,
if (argc < 1)
fatal ("ROOTDIR argument must be specified");
after_bind_arg_index = 0;
argv_iter = argv;
while (after_bind_arg_index < argc
&& strcmp (argv[after_bind_arg_index], "--bind") == 0)
after_mount_arg_index = 0;
while (after_mount_arg_index < argc)
{
if ((argc - after_bind_arg_index) < 3)
fatal ("--bind takes two arguments");
after_bind_arg_index += 3;
argv_iter += 3;
}
const char *arg = argv[after_mount_arg_index];
BindMount *mount = NULL;
if ((argc - after_bind_arg_index) < 2)
fatal ("usage: %s [--bind SOURCE DEST] ROOTDIR PROGRAM ARGS...", argv0);
chroot_dir = argv[after_bind_arg_index];
program = argv[after_bind_arg_index+1];
program_argv = argv + after_bind_arg_index + 1;
if (n_mounts >= max_mounts)
fatal ("Too many mounts (maximum of %u)", n_mounts);
n_mounts++;
if (strcmp (arg, "--mount-bind") == 0)
{
if ((argc - after_mount_arg_index) < 3)
fatal ("--mount-bind takes two arguments");
mount = malloc (sizeof (BindMount));
mount->source = argv[after_mount_arg_index+1];
mount->dest = argv[after_mount_arg_index+2];
mount->readonly = 0;
mount->next = bind_mounts;
bind_mounts = mount;
after_mount_arg_index += 3;
}
else if (strcmp (arg, "--mount-readonly") == 0)
{
BindMount *mount;
if ((argc - after_mount_arg_index) < 2)
fatal ("--mount-readonly takes one argument");
mount = malloc (sizeof (BindMount));
mount->source = NULL;
mount->dest = argv[after_mount_arg_index+1];
mount->readonly = 1;
mount->next = bind_mounts;
bind_mounts = mount;
after_mount_arg_index += 2;
}
else
break;
}
bind_mounts = reverse_bind_mount_list (bind_mounts);
if ((argc - after_mount_arg_index) < 2)
fatal ("usage: %s [--mount-readonly DIR] [--mount-bind SOURCE DEST] ROOTDIR PROGRAM ARGS...", argv0);
chroot_dir = argv[after_mount_arg_index];
program = argv[after_mount_arg_index+1];
program_argv = argv + after_mount_arg_index + 1;
if (getresgid (&rgid, &egid, &sgid) < 0)
fatal_errno ("getresgid");
@ -145,19 +208,29 @@ main (int argc,
fatal_errno ("mount(/, MS_PRIVATE | MS_REC)");
/* Now let's set up our bind mounts */
for (i = 0; i < after_bind_arg_index; i += 3)
for (bind_mount_iter = bind_mounts; bind_mount_iter; bind_mount_iter = bind_mount_iter->next)
{
const char *bind_arg = argv[0]; /* --bind */
const char *bind_source = argv[i+1];
const char *bind_target = argv[i+2];
char *bind_abs_target;
char *dest;
assert (strcmp (bind_arg, "--bind") == 0);
asprintf (&dest, "%s%s", chroot_dir, bind_mount_iter->dest);
asprintf (&bind_abs_target, "%s%s", chroot_dir, bind_target);
if (mount (bind_source, bind_abs_target, NULL, MS_BIND | MS_PRIVATE, NULL) < 0)
fatal_errno ("mount (MS_BIND)");
free (bind_abs_target);
if (bind_mount_iter->readonly)
{
if (mount (dest, dest,
NULL, MS_BIND | MS_PRIVATE, NULL) < 0)
fatal_errno ("mount (MS_BIND)");
if (mount (dest, dest,
NULL, MS_BIND | MS_PRIVATE | MS_REMOUNT | MS_RDONLY, NULL) < 0)
fatal_errno ("mount (MS_BIND | MS_RDONLY)");
}
else
{
if (mount (bind_mount_iter->source, dest,
NULL, MS_BIND | MS_PRIVATE, NULL) < 0)
fatal_errno ("mount (MS_BIND)");
}
free (dest);
}
/* Actually perform the chroot. */