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mount-v2: enter the mount namesapce to propagation properties

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A kernel change (commit 12f147ddd6de, "do_change_type(): refuse to
operate on unmounted/not ours mounts") modified how mount propagation
properties can be changed. Previously, these properties could be changed
from any mount namespace. Now, they can only be modified from the
specific mount namespace where the target mount is actually mounted

This commit addresses this new restriction by ensuring that CRIU enters the
correct mount namespace before attempting to restore mount propagation
properties (MS_SLAVE or MS_SHARED) for a mount.

Signed-off-by: Andrei Vagin <avagin@gmail.com>
This commit is contained in:
Andrei Vagin 2025-07-25 00:05:06 +00:00
parent 6f0e4e848b
commit 27eb6c57c5
1 changed files with 25 additions and 12 deletions
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37
criu/mount-v2.c
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@ -933,8 +933,12 @@ static int move_mount_set_group(int src_id, char *source, int dst_id)
static int restore_one_sharing(struct sharing_group *sg, struct mount_info *target) static int restore_one_sharing(struct sharing_group *sg, struct mount_info *target)
{ {
int nsfd = -1, orig_nsfd = -1, exit_code = -1;
char target_path[PATH_MAX]; char target_path[PATH_MAX];
int target_fd; int target_fd = -1;
if (!sg->master_id && !sg->shared_id)
return 0;
target_fd = fdstore_get(target->mnt_fd_id); target_fd = fdstore_get(target->mnt_fd_id);
BUG_ON(target_fd < 0); BUG_ON(target_fd < 0);
@ -949,8 +953,7 @@ static int restore_one_sharing(struct sharing_group *sg, struct mount_info *targ
first = get_first_mount(sg->parent); first = get_first_mount(sg->parent);
if (move_mount_set_group(first->mnt_fd_id, NULL, target->mnt_fd_id)) { if (move_mount_set_group(first->mnt_fd_id, NULL, target->mnt_fd_id)) {
pr_err("Failed to copy sharing from %d to %d\n", first->mnt_id, target->mnt_id); pr_err("Failed to copy sharing from %d to %d\n", first->mnt_id, target->mnt_id);
close(target_fd); goto err;
return -1;
} }
} else { } else {
/* /*
@ -962,16 +965,23 @@ static int restore_one_sharing(struct sharing_group *sg, struct mount_info *targ
*/ */
if (move_mount_set_group(-1, sg->source, target->mnt_fd_id)) { if (move_mount_set_group(-1, sg->source, target->mnt_fd_id)) {
pr_err("Failed to copy sharing from source %s to %d\n", sg->source, target->mnt_id); pr_err("Failed to copy sharing from source %s to %d\n", sg->source, target->mnt_id);
close(target_fd); goto err;
return -1;
} }
} }
}
nsfd = fdstore_get(target->nsid->mnt.nsfd_id);
if (nsfd < 0)
goto err;
if (switch_ns_by_fd(nsfd, &mnt_ns_desc, &orig_nsfd))
goto err;
if (sg->master_id) {
/* Convert shared_id to master_id */ /* Convert shared_id to master_id */
if (mount(NULL, target_path, NULL, MS_SLAVE, NULL)) { if (mount(NULL, target_path, NULL, MS_SLAVE, NULL)) {
pr_perror("Failed to make mount %d slave", target->mnt_id); pr_perror("Failed to make mount %d slave", target->mnt_id);
close(target_fd); goto err;
return -1;
} }
} }
@ -979,13 +989,16 @@ static int restore_one_sharing(struct sharing_group *sg, struct mount_info *targ
if (sg->shared_id) { if (sg->shared_id) {
if (mount(NULL, target_path, NULL, MS_SHARED, NULL)) { if (mount(NULL, target_path, NULL, MS_SHARED, NULL)) {
pr_perror("Failed to make mount %d shared", target->mnt_id); pr_perror("Failed to make mount %d shared", target->mnt_id);
close(target_fd); goto err;
return -1;
} }
} }
close(target_fd); exit_code = 0;
err:
return 0; close_safe(&target_fd);
close_safe(&nsfd);
if (orig_nsfd >= 0 && restore_ns(orig_nsfd, &mnt_ns_desc))
exit_code = -1;
return exit_code;
} }
static int restore_one_sharing_group(struct sharing_group *sg) static int restore_one_sharing_group(struct sharing_group *sg)