diff options
| -rw-r--r-- | sys/vm/vm_mmap.c | 31 |
1 files changed, 18 insertions, 13 deletions
diff --git a/sys/vm/vm_mmap.c b/sys/vm/vm_mmap.c index 7d7855d341f..3d6ab555d69 100644 --- a/sys/vm/vm_mmap.c +++ b/sys/vm/vm_mmap.c @@ -1,4 +1,4 @@ -/* $OpenBSD: vm_mmap.c,v 1.11 1998/02/18 23:36:12 deraadt Exp $ */ +/* $OpenBSD: vm_mmap.c,v 1.12 1998/02/19 22:00:27 niklas Exp $ */ /* $NetBSD: vm_mmap.c,v 1.47 1996/03/16 23:15:23 christos Exp $ */ /* @@ -213,7 +213,13 @@ sys_mmap(p, v, retval) if (fp->f_type != DTYPE_VNODE) return (EINVAL); vp = (struct vnode *)fp->f_data; - if (vp->v_type != VREG && vp->v_type != VCHR) + + /* + * Only files and cdevs are mappable, and cdevs does not + * provide private mappings of any kind. + */ + if (vp->v_type != VREG && + (vp->v_type != VCHR || (flags & (MAP_PRIVATE|MAP_COPY)))) return (EINVAL); /* * XXX hack to handle use of /dev/zero to map anon @@ -238,17 +244,16 @@ sys_mmap(p, v, retval) else if (prot & PROT_READ) return (EACCES); - if ((flags & MAP_SHARED) != 0 || - ((flags & (MAP_PRIVATE|MAP_SHARED|MAP_COPY)) == MAP_FILE && - vp->v_type == VCHR)) { - if (fp->f_flag & FWRITE) - maxprot |= VM_PROT_WRITE; - } else if (flags & MAP_SHARED) { - if (fp->f_flag & FWRITE) - maxprot |= VM_PROT_WRITE; - else if (prot & PROT_WRITE) - return (EACCES); - } else + /* + * If we are sharing potential changes (either via MAP_SHARED + * or via the implicit sharing of character device mappings), + * and we are trying to get write permission although we + * opened it without asking for it, bail out. + */ + if (((flags & MAP_SHARED) != 0 || vp->v_type == VCHR) && + (fp->f_flag & FWRITE) == 0 && (prot & PROT_WRITE) != 0) + return (EACCES); + else maxprot |= VM_PROT_WRITE; handle = (caddr_t)vp; } else { |