This saves the uid/gid of the sk_peercred structure in the checkpoint
stream. On restart, it uses may_setuid() and may_setgid() to determine
if the uid/gid from the checkpoint stream may be used.
Signed-off-by: Dan Smith <danms@xxxxxxxxxx>
---
include/linux/checkpoint_hdr.h | 2 ++
net/unix/checkpoint.c | 29 ++++++++++++++++-------------
2 files changed, 18 insertions(+), 13 deletions(-)
diff --git a/include/linux/checkpoint_hdr.h b/include/linux/checkpoint_hdr.h
index 829ff2d..6c6780c 100644
--- a/include/linux/checkpoint_hdr.h
+++ b/include/linux/checkpoint_hdr.h
@@ -523,6 +523,8 @@ struct ckpt_hdr_socket_unix {
struct ckpt_hdr h;
__s32 this;
__s32 peer;
+ __u32 peercred_uid;
+ __u32 peercred_gid;
__u32 flags;
__u32 laddr_len;
__u32 raddr_len;
diff --git a/net/unix/checkpoint.c b/net/unix/checkpoint.c
index 841d25d..eb19e66 100644
--- a/net/unix/checkpoint.c
+++ b/net/unix/checkpoint.c
@@ -3,6 +3,7 @@
#include <linux/fs_struct.h>
#include <linux/checkpoint.h>
#include <linux/checkpoint_hdr.h>
+#include <linux/user.h>
#include <net/af_unix.h>
#include <net/tcp_states.h>
@@ -98,6 +99,9 @@ int sock_unix_checkpoint(struct ckpt_ctx *ctx,
goto out;
}
+ un->peercred_uid = socket->sk->sk_peercred.uid;
+ un->peercred_gid = socket->sk->sk_peercred.gid;
+
ret = ckpt_write_obj(ctx, (struct ckpt_hdr *) h);
if (ret < 0)
goto out;
@@ -225,19 +229,6 @@ static int sock_unix_join(struct ckpt_ctx *ctx,
unix_sk(a)->peer = b;
unix_sk(b)->peer = a;
- /* TODO:
- * Checkpoint the credentials, restore them here if the values match
- * the restored creds or we may_setuid()
- */
-
- a->sk_peercred.pid = task_tgid_vnr(current);
- a->sk_peercred.uid = ctx->realcred->uid;
- a->sk_peercred.gid = ctx->realcred->gid;
-
- b->sk_peercred.pid = a->sk_peercred.pid;
- b->sk_peercred.uid = a->sk_peercred.uid;
- b->sk_peercred.gid = a->sk_peercred.gid;
-
if (!UNIX_ADDR_EMPTY(un->raddr_len))
addr = sock_unix_makeaddr(&un->raddr, un->raddr_len);
else if (!UNIX_ADDR_EMPTY(un->laddr_len))
@@ -303,6 +294,18 @@ static int sock_unix_restore_connected(struct ckpt_ctx *ctx,
goto out;
}
+ this->sk_peercred.pid = task_tgid_vnr(current);
+
+ if (may_setuid(ctx->realcred->user->user_ns, un->peercred_uid) &&
+ may_setgid(ctx->realcred->group_info, un->peercred_gid)) {
+ this->sk_peercred.uid = un->peercred_uid;
+ this->sk_peercred.gid = un->peercred_gid;
+ } else {
+ ckpt_debug("peercred %i:%i would require setuid",
+ un->peercred_uid, un->peercred_gid);
+ return -1;
+ }
+
/* Prime the socket's buffer limit with the maximum. These will be
* overwritten with the values in the checkpoint stream in a later
* phase.
--
1.6.0.4
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