From b2e4f544fddc812d6fe802bab5f600b4b783f45d Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 23 May 2012 16:39:45 -0600 Subject: userns: Convert net/core/scm.c to use kuids and kgids 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 Acked-by: David S. Miller Acked-by: Serge Hallyn Signed-off-by: Eric W. Biederman --- net/core/scm.c | 31 +++++++++++++++++++++++-------- 1 file changed, 23 insertions(+), 8 deletions(-) (limited to 'net/core/scm.c') 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; } -- cgit v1.1