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authorEric W. Biederman <ebiederm@xmission.com>2012-05-24 02:39:45 +0400
committerEric W. Biederman <ebiederm@xmission.com>2012-08-15 08:41:58 +0400
commitb2e4f544fddc812d6fe802bab5f600b4b783f45d (patch)
tree4b17b92fc11ff292a8c683217e8027c2d3fee09e /net/core/scm.c
parent81abe27b10af98f861c955be63da700938dd59c1 (diff)
downloadlinux-b2e4f544fddc812d6fe802bab5f600b4b783f45d.tar.xz
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 <eric.dumazet@gmail.com> Acked-by: David S. Miller <davem@davemloft.net> Acked-by: Serge Hallyn <serge.hallyn@canonical.com> Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'net/core/scm.c')
-rw-r--r--net/core/scm.c31
1 files changed, 23 insertions, 8 deletions
diff --git a/net/core/scm.c b/net/core/scm.c
index 8f6ccfd68ef4..5472ae7a0657 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;
}