diff options
| -rw-r--r-- | lib/libc/sys/msgctl.2 | 4 | ||||
| -rw-r--r-- | sys/kern/sysv_msg.c | 7 |
2 files changed, 8 insertions, 3 deletions
diff --git a/lib/libc/sys/msgctl.2 b/lib/libc/sys/msgctl.2 index 1ca61ed77b2a..745b365c4d93 100644 --- a/lib/libc/sys/msgctl.2 +++ b/lib/libc/sys/msgctl.2 @@ -31,7 +31,7 @@ .\" .\" $FreeBSD$ .\"/ -.Dd July 9, 2009 +.Dd July 9, 2020 .Dt MSGCTL 2 .Os .Sh NAME @@ -63,8 +63,6 @@ and contains (amongst others) the following members: .Bd -literal struct msqid_ds { struct ipc_perm msg_perm; /* msg queue permission bits */ - struct msg *__msg_first; /* kernel data, don't use */ - struct msg *__msg_last; /* kernel data, don't use */ msglen_t msg_cbytes; /* number of bytes in use on the queue */ msgqnum_t msg_qnum; /* number of msgs in the queue */ msglen_t msg_qbytes; /* max # of bytes on the queue */ diff --git a/sys/kern/sysv_msg.c b/sys/kern/sysv_msg.c index de6faafde286..aab4551357c2 100644 --- a/sys/kern/sysv_msg.c +++ b/sys/kern/sysv_msg.c @@ -613,6 +613,13 @@ kern_msgctl(struct thread *td, int msqid, int cmd, struct msqid_ds *msqbuf) *msqbuf = msqkptr->u; if (td->td_ucred->cr_prison != msqkptr->cred->cr_prison) msqbuf->msg_perm.key = IPC_PRIVATE; + + /* + * Try to hide the fact that the structure layout is shared by + * both the kernel and userland. These pointers are not useful + * to userspace. + */ + msqbuf->__msg_first = msqbuf->__msg_last = NULL; break; default: |