Author: rmacklem Date: Tue Jan 31 02:11:05 2012 New Revision: 230801 URL: http://svn.freebsd.org/changeset/base/230801
Log: jwd@ reported a problem via email to freebsd-fs@ on Aug 25, 2011 under the subject "F_RDLCK lock to FreeBSD NFS fails to R/O target file". This occurred because the server side NLM always checked for VWRITE access, irrespective of the type of lock request. This patch replaces VOP_ACCESS(..VWRITE..) with one appropriate to the lock operation. It allows unlock and lock cancellation to be done without a check of VOP_ACCESS(), so that files can't be left locked indefinitely after the file permissions have been changed. Discussed with: zack Submitted by: jwd (earlier version) Reviewed by: dfr MFC after: 2 weeks Modified: head/sys/nlm/nlm_prot_impl.c Modified: head/sys/nlm/nlm_prot_impl.c ============================================================================== --- head/sys/nlm/nlm_prot_impl.c Tue Jan 31 01:51:30 2012 (r230800) +++ head/sys/nlm/nlm_prot_impl.c Tue Jan 31 02:11:05 2012 (r230801) @@ -1775,10 +1775,10 @@ struct vfs_state { static int nlm_get_vfs_state(struct nlm_host *host, struct svc_req *rqstp, - fhandle_t *fhp, struct vfs_state *vs) + fhandle_t *fhp, struct vfs_state *vs, accmode_t accmode) { int error, exflags; - struct ucred *cred = NULL, *credanon; + struct ucred *cred = NULL, *credanon = NULL; memset(vs, 0, sizeof(*vs)); @@ -1788,14 +1788,19 @@ nlm_get_vfs_state(struct nlm_host *host, } vs->vs_vfslocked = VFS_LOCK_GIANT(vs->vs_mp); - error = VFS_CHECKEXP(vs->vs_mp, (struct sockaddr *)&host->nh_addr, - &exflags, &credanon, NULL, NULL); - if (error) - goto out; + /* accmode == 0 means don't check, since it is an unlock. */ + if (accmode != 0) { + error = VFS_CHECKEXP(vs->vs_mp, + (struct sockaddr *)&host->nh_addr, &exflags, &credanon, + NULL, NULL); + if (error) + goto out; - if (exflags & MNT_EXRDONLY || (vs->vs_mp->mnt_flag & MNT_RDONLY)) { - error = EROFS; - goto out; + if (exflags & MNT_EXRDONLY || + (vs->vs_mp->mnt_flag & MNT_RDONLY)) { + error = EROFS; + goto out; + } } error = VFS_FHTOVP(vs->vs_mp, &fhp->fh_fid, LK_EXCLUSIVE, &vs->vs_vp); @@ -1803,22 +1808,31 @@ nlm_get_vfs_state(struct nlm_host *host, goto out; vs->vs_vnlocked = TRUE; - if (!svc_getcred(rqstp, &cred, NULL)) { - error = EINVAL; - goto out; - } - if (cred->cr_uid == 0 || (exflags & MNT_EXPORTANON)) { - crfree(cred); - cred = credanon; - credanon = NULL; - } + if (accmode != 0) { + if (!svc_getcred(rqstp, &cred, NULL)) { + error = EINVAL; + goto out; + } + if (cred->cr_uid == 0 || (exflags & MNT_EXPORTANON)) { + crfree(cred); + cred = credanon; + credanon = NULL; + } - /* - * Check cred. - */ - error = VOP_ACCESS(vs->vs_vp, VWRITE, cred, curthread); - if (error) - goto out; + /* + * Check cred. + */ + error = VOP_ACCESS(vs->vs_vp, accmode, cred, curthread); + /* + * If this failed and accmode != VWRITE, try again with + * VWRITE to maintain backwards compatibility with the + * old code that always used VWRITE. + */ + if (error != 0 && accmode != VWRITE) + error = VOP_ACCESS(vs->vs_vp, VWRITE, cred, curthread); + if (error) + goto out; + } #if __FreeBSD_version < 800011 VOP_UNLOCK(vs->vs_vp, 0, curthread); @@ -1872,6 +1886,7 @@ nlm_do_test(nlm4_testargs *argp, nlm4_te struct nlm_host *host, *bhost; int error, sysid; struct flock fl; + accmode_t accmode; memset(result, 0, sizeof(*result)); memset(&vs, 0, sizeof(vs)); @@ -1897,7 +1912,8 @@ nlm_do_test(nlm4_testargs *argp, nlm4_te goto out; } - error = nlm_get_vfs_state(host, rqstp, &fh, &vs); + accmode = argp->exclusive ? VWRITE : VREAD; + error = nlm_get_vfs_state(host, rqstp, &fh, &vs, accmode); if (error) { result->stat.stat = nlm_convert_error(error); goto out; @@ -1968,6 +1984,7 @@ nlm_do_lock(nlm4_lockargs *argp, nlm4_re struct nlm_host *host; int error, sysid; struct flock fl; + accmode_t accmode; memset(result, 0, sizeof(*result)); memset(&vs, 0, sizeof(vs)); @@ -2002,7 +2019,8 @@ nlm_do_lock(nlm4_lockargs *argp, nlm4_re goto out; } - error = nlm_get_vfs_state(host, rqstp, &fh, &vs); + accmode = argp->exclusive ? VWRITE : VREAD; + error = nlm_get_vfs_state(host, rqstp, &fh, &vs, accmode); if (error) { result->stat.stat = nlm_convert_error(error); goto out; @@ -2181,7 +2199,7 @@ nlm_do_cancel(nlm4_cancargs *argp, nlm4_ goto out; } - error = nlm_get_vfs_state(host, rqstp, &fh, &vs); + error = nlm_get_vfs_state(host, rqstp, &fh, &vs, (accmode_t)0); if (error) { result->stat.stat = nlm_convert_error(error); goto out; @@ -2270,7 +2288,7 @@ nlm_do_unlock(nlm4_unlockargs *argp, nlm goto out; } - error = nlm_get_vfs_state(host, rqstp, &fh, &vs); + error = nlm_get_vfs_state(host, rqstp, &fh, &vs, (accmode_t)0); if (error) { result->stat.stat = nlm_convert_error(error); goto out; _______________________________________________ svn-src-head@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/svn-src-head To unsubscribe, send any mail to "svn-src-head-unsubscr...@freebsd.org"