From: Stanislav Kinsburskiy <skinsbur...@parallels.com>
If there is another dentry for the unlinked socket inode, then first create a
hardlink for this dentry, then rebind and unlink.
Signed-off-by: Stanislav Kinsburskiy <skinsbur...@parallels.com>
---
include/linux/cpt_image.h | 2 -
kernel/cpt/rst_socket.c | 96 ++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 95 insertions(+), 3 deletions(-)
diff --git a/include/linux/cpt_image.h b/include/linux/cpt_image.h
index 75fa878..394fe0f 100644
--- a/include/linux/cpt_image.h
+++ b/include/linux/cpt_image.h
@@ -964,7 +964,7 @@ struct cpt_sock_image
__u32 cpt_i_uid;
__u32 cpt_i_gid;
- __u32 cpt_d_alias[128/4];
+ __u32 cpt_d_alias[108/4];
__u32 cpt_d_aliaslen;
__u32 __cpt_pad15;
diff --git a/kernel/cpt/rst_socket.c b/kernel/cpt/rst_socket.c
index 79a9dab..beb7857 100644
--- a/kernel/cpt/rst_socket.c
+++ b/kernel/cpt/rst_socket.c
@@ -189,6 +189,85 @@ static int unix_bind_to_path(struct socket *sock, char
*name,
return err;
}
+static struct dentry *select_link_dentry(char *name, struct dentry *dirde,
+ cpt_context_t *ctx)
+{
+ struct dentry *link;
+ int i;
+
+ for (i=0; i<100; i++) {
+ unsigned int rnd = net_random();
+
+ sprintf(name, "SOCK.%08x", rnd);
+
+ link = lookup_one_len(name, dirde, strlen(name));
+ if (IS_ERR(link)) {
+ eprintk_ctx("Can't lookup %s\n", name);
+ return link;
+ }
+
+ if (!link->d_inode)
+ return link;
+
+ dput(link);
+ }
+
+ eprintk_ctx("failed to allocate deleted socket dentry\n");
+ return ERR_PTR(-ELOOP);
+}
+
+static int rst_create_link(struct dentry *d, char *name,
+ struct cpt_context *ctx)
+{
+ int err;
+ struct dentry *dirde, *hardde;
+
+ dirde = d->d_parent;
+
+ mutex_lock(&dirde->d_inode->i_mutex);
+
+ hardde = select_link_dentry(name, dirde, ctx);
+ if (IS_ERR(hardde)) {
+ eprintk_ctx("Can't find hardde: %s\n", name);
+ err = PTR_ERR(hardde);
+ goto out_unlock;
+ }
+
+ err = vfs_link(d, dirde->d_inode, hardde);
+ if (err)
+ eprintk_ctx("error hardlink %s, %d\n", name, err);
+
+ dput(hardde);
+out_unlock:
+ mutex_unlock(&dirde->d_inode->i_mutex);
+ return err;
+}
+
+static int create_deleted_socket_link(char *name, char *alias, struct vfsmount
*mnt,
+ cpt_context_t *ctx)
+{
+ struct nameidata nd;
+ int err;
+
+ strcpy(name, alias);
+
+ err = rst_path_lookup_at(mnt, mnt->mnt_root, alias, 0, &nd);
+ if (err) {
+ eprintk_ctx("failed to lookup deleted socket alias\n");
+ return err;
+ }
+
+ err = rst_create_link(nd.path.dentry, strrchr(name, '/') + 1, ctx);
+ path_put(&nd.path);
+ if (err) {
+ eprintk_ctx("%s: failed to link socket alias\n", __func__);
+ return err;
+ }
+
+ printk("link path: %s\n", name);
+ return 0;
+}
+
static int unix_bind_to_mntref(struct sock *sk, char *name,
struct sockaddr* addr, int addrlen,
struct cpt_sock_image *si, cpt_context_t *ctx)
@@ -222,6 +301,13 @@ static int unix_bind_to_mntref(struct sock *sk, char *name,
return -EINVAL;
}
+ if (si->cpt_sockflags & CPT_SOCK_DELETED) {
+ err = create_deleted_socket_link(name, (char *)si->cpt_d_alias,
+ (struct vfsmount
*)mntobj->o_obj, ctx);
+ if (err)
+ return err;
+ }
+
if (strlen(name) < mntobj->o_lock) {
eprintk_ctx("%s: unix socket with too short name (%d %s)\n",
__func__, mntobj->o_lock, name);
@@ -242,7 +328,12 @@ static int unix_bind_to_mntref(struct sock *sk, char *name,
}
bi.next = NULL;
- return rebind_unix_socket(mntobj->o_obj, &bi, LOOKUP_DIVE);
+ err = rebind_unix_socket(mntobj->o_obj, &bi, LOOKUP_DIVE);
+
+ if (si->cpt_sockflags & CPT_SOCK_DELETED)
+ sc_unlink(name);
+
+ return err;
}
static int can_be_rebound_by_mntref(struct socket *sock,
@@ -252,7 +343,8 @@ static int can_be_rebound_by_mntref(struct socket *sock,
if (ctx->image_version < CPT_VERSION_18_4)
return 0;
- if (si->cpt_sockflags & CPT_SOCK_DELETED)
+ if ((si->cpt_sockflags & CPT_SOCK_DELETED) &&
+ (!cpt_object_has(si, cpt_d_alias) || !si->cpt_d_aliaslen))
return 0;
if (si->cpt_vfsmount_ref == CPT_NULL)
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