diff options
Diffstat (limited to 'sys/kern/vfs_vnops.c')
| -rw-r--r-- | sys/kern/vfs_vnops.c | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/sys/kern/vfs_vnops.c b/sys/kern/vfs_vnops.c index 86b12230afdf..84c34501de4b 100644 --- a/sys/kern/vfs_vnops.c +++ b/sys/kern/vfs_vnops.c @@ -136,6 +136,11 @@ static u_long vn_io_faults_cnt; SYSCTL_ULONG(_debug, OID_AUTO, vn_io_faults, CTLFLAG_RD, &vn_io_faults_cnt, 0, "Count of vn_io_fault lock avoidance triggers"); +static int vfs_allow_read_dir = 0; +SYSCTL_INT(_security_bsd, OID_AUTO, allow_read_dir, CTLFLAG_RW, + &vfs_allow_read_dir, 0, + "Enable read(2) of directory by root for filesystems that support it"); + /* * Returns true if vn_io_fault mode of handling the i/o request should * be used. @@ -1216,6 +1221,20 @@ vn_io_fault(struct file *fp, struct uio *uio, struct ucred *active_cred, doio = uio->uio_rw == UIO_READ ? vn_read : vn_write; vp = fp->f_vnode; + + /* + * The ability to read(2) on a directory has historically been + * allowed for all users, but this can and has been the source of + * at least one security issue in the past. As such, it is now hidden + * away behind a sysctl for those that actually need it to use it. + */ + if (vp->v_type == VDIR) { + KASSERT(uio->uio_rw == UIO_READ, + ("illegal write attempted on a directory")); + if (!vfs_allow_read_dir) + return (EISDIR); + } + foffset_lock_uio(fp, uio, flags); if (do_vn_io_fault(vp, uio)) { args.kind = VN_IO_FAULT_FOP; |