LinuxLists.cc - [PATCH 01/21] userns: Convert net/core/scm.c to use kuids and kgids

2012-08-13 20:19:38

Subject: [PATCH 01/21] userns: Convert net/core/scm.c to use kuids and kgids

From: "Eric W. Biederman" <[email protected]>

With the existence of kuid_t and kgid_t we can take this further
and remove the usage of struct cred altogether, ensuring we
don't get cache line misses from reference counts. For now
however start simply and do a straight forward conversion
I can be certain is correct.

In cred_to_ucred use from_kuid_munged and from_kgid_munged
as these values are going directly to userspace and we want to use
the userspace safe values not -1 when reporting a value that does not
map. The earlier conversion that used from_kuid was buggy in that
respect. Oops.

Cc: Eric Dumazet <[email protected]>
Acked-by: Serge Hallyn <[email protected]>
Signed-off-by: Eric W. Biederman <[email protected]>
---
net/core/scm.c | 31 +++++++++++++++++++++++--------
net/core/sock.c | 4 ++--
2 files changed, 25 insertions(+), 10 deletions(-)

diff --git a/net/core/scm.c b/net/core/scm.c
index 8f6ccfd..5472ae7 100644
--- a/net/core/scm.c
+++ b/net/core/scm.c
@@ -45,12 +45,17 @@
static __inline__ int scm_check_creds(struct ucred *creds)
{
const struct cred *cred = current_cred();
+ kuid_t uid = make_kuid(cred->user_ns, creds->uid);
+ kgid_t gid = make_kgid(cred->user_ns, creds->gid);
+
+ if (!uid_valid(uid) || !gid_valid(gid))
+ return -EINVAL;

if ((creds->pid == task_tgid_vnr(current) || capable(CAP_SYS_ADMIN)) &&
- ((creds->uid == cred->uid || creds->uid == cred->euid ||
- creds->uid == cred->suid) || capable(CAP_SETUID)) &&
- ((creds->gid == cred->gid || creds->gid == cred->egid ||
- creds->gid == cred->sgid) || capable(CAP_SETGID))) {
+ ((uid_eq(uid, cred->uid) || uid_eq(uid, cred->euid) ||
+ uid_eq(uid, cred->suid)) || capable(CAP_SETUID)) &&
+ ((gid_eq(gid, cred->gid) || gid_eq(gid, cred->egid) ||
+ gid_eq(gid, cred->sgid)) || capable(CAP_SETGID))) {
return 0;
}
return -EPERM;
@@ -149,6 +154,9 @@ int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
goto error;
break;
case SCM_CREDENTIALS:
+ {
+ kuid_t uid;
+ kgid_t gid;
if (cmsg->cmsg_len != CMSG_LEN(sizeof(struct ucred)))
goto error;
memcpy(&p->creds, CMSG_DATA(cmsg), sizeof(struct ucred));
@@ -166,22 +174,29 @@ int __scm_send(struct socket *sock, struct msghdr *msg, struct scm_cookie *p)
p->pid = pid;
}

+ err = -EINVAL;
+ uid = make_kuid(current_user_ns(), p->creds.uid);
+ gid = make_kgid(current_user_ns(), p->creds.gid);
+ if (!uid_valid(uid) || !gid_valid(gid))
+ goto error;
+
if (!p->cred ||
- (p->cred->euid != p->creds.uid) ||
- (p->cred->egid != p->creds.gid)) {
+ !uid_eq(p->cred->euid, uid) ||
+ !gid_eq(p->cred->egid, gid)) {
struct cred *cred;
err = -ENOMEM;
cred = prepare_creds();
if (!cred)
goto error;

- cred->uid = cred->euid = p->creds.uid;
- cred->gid = cred->egid = p->creds.gid;
+ cred->uid = cred->euid = uid;
+ cred->gid = cred->egid = gid;
if (p->cred)
put_cred(p->cred);
p->cred = cred;
}
break;
+ }
default:
goto error;
}
diff --git a/net/core/sock.c b/net/core/sock.c
index 6b654b3..9c7fe4f 100644
--- a/net/core/sock.c
+++ b/net/core/sock.c
@@ -868,8 +868,8 @@ void cred_to_ucred(struct pid *pid, const struct cred *cred,
if (cred) {
struct user_namespace *current_ns = current_user_ns();

- ucred->uid = from_kuid(current_ns, cred->euid);
- ucred->gid = from_kgid(current_ns, cred->egid);
+ ucred->uid = from_kuid_munged(current_ns, cred->euid);
+ ucred->gid = from_kgid_munged(current_ns, cred->egid);
}
}
EXPORT_SYMBOL_GPL(cred_to_ucred);
--
1.7.5.4

2012-08-13 20:20:19

Subject: [PATCH 01/21] userns: Convert net/core/scm.c to use kuids and kgids

Subject: [PATCH 05/21] userns: Make seq_file's user namespace accessible

Subject: [PATCH 10/21] userns: Convert net/ax25 to use kuid_t where appropriate

Subject: [PATCH 16/21] userns: Convert cls_flow to work with user namespaces enabled

Subject: [PATCH 17/21] userns: Convert xt_LOG to print socket kuids and kgids as uids and gids

Subject: Re: [PATCH 06/21] userns: Print out socket uids in a user namespace aware fashion.

Subject: [PATCH 19/21] userns: xt_owner: Add basic user namespace support.

Subject: [PATCH 20/21] userns: Make the airo wireless driver use kuids for proc uids and gids

Subject: [PATCH 12/21] userns: Implement sk_user_ns

Subject: [PATCH 18/21] userns xt_recent: Specify the owner/group of ip_list_perms in the initial user namespace

Subject: [PATCH 11/21] netlink: Make the sending netlink socket availabe in NETLINK_CB

Subject: [PATCH 21/21] userns: Convert tun/tap to use kuid and kgid where appropriate

Subject: [PATCH 15/21] net sched: Pass the skb into change so it can access NETLINK_CB

Subject: [PATCH 13/21] userns: Teach inet_diag to work with user namespaces

Subject: [PATCH 14/21] userns: nfnetlink_log: Report socket uids in the log sockets user namespace

Subject: [PATCH 09/21] pidns: Export free_pid_ns

Subject: [PATCH 06/21] userns: Print out socket uids in a user namespace aware fashion.

Subject: [PATCH 08/21] net ip6 flowlabel: Make owner a union of struct pid * and kuid_t

Subject: [PATCH 07/21] userns: Use kgids for sysctl_ping_group_range

Subject: [PATCH 04/21] userns: Allow USER_NS and NET simultaneously in Kconfig

Subject: [PATCH 03/21] userns: Convert sock_i_uid to return a kuid_t

Subject: [PATCH 02/21] userns: Convert __dev_set_promiscuity to use kuids in audit logs

Subject: Re: [PATCH 13/21] userns: Teach inet_diag to work with user namespaces

Subject: Re: [PATCH 06/21] userns: Print out socket uids in a user namespace aware fashion.

Subject: Re: [PATCH 06/21] userns: Print out socket uids in a user namespace aware fashion.

Subject: Re: [PATCH 15/21] net sched: Pass the skb into change so it can access NETLINK_CB

Subject: Re: [PATCH 07/21] userns: Use kgids for sysctl_ping_group_range