svn commit: r203220 - projects/capabilities8/sys/kern

[Robert Watson]

Author: rwatson
Date: Sat Jan 30 19:25:18 2010
New Revision: 203220
URL: http://svn.freebsd.org/changeset/base/203220

Log:
  Merge c171326 from the p4 TrustedBSD Capabilities branch to capabilities8:
  
    Enable fchmodat(2).
  
  Submitted by:	Jonathan Anderson <jonathan.anderson at cl.cam.ac.uk>

Modified:
  projects/capabilities8/sys/kern/capabilities.conf
  projects/capabilities8/sys/kern/init_sysent.c
  projects/capabilities8/sys/kern/vfs_syscalls.c

Modified: projects/capabilities8/sys/kern/capabilities.conf
==============================================================================
--- projects/capabilities8/sys/kern/capabilities.conf	Sat Jan 30 19:23:56 2010	(r203219)
+++ projects/capabilities8/sys/kern/capabilities.conf	Sat Jan 30 19:25:18 2010	(r203220)
@@ -38,7 +38,7 @@
 ## - sys_exit(2), abort2(2) and close(2) are very important.
 ## - Sorted alphabetically, please keep it that way.
 ##
-## $P4: //depot/projects/trustedbsd/capabilities/src/sys/kern/capabilities.conf#23 $
+## $P4: //depot/projects/trustedbsd/capabilities/src/sys/kern/capabilities.conf#24 $
 ##
 
 ##
@@ -453,10 +453,11 @@ obreak
 olio_listio
 
 ##
-## Allow faccessat(2) and openat(2), which we have constrained to prevent accessing
+## Allow some of the *at(2) calls, which we have constrained to prevent accessing
 ## files which are not "under" the directory FD given to the syscall.
 ##
 faccessat
+fchmodat
 openat
 
 ##

Modified: projects/capabilities8/sys/kern/init_sysent.c
==============================================================================
--- projects/capabilities8/sys/kern/init_sysent.c	Sat Jan 30 19:23:56 2010	(r203219)
+++ projects/capabilities8/sys/kern/init_sysent.c	Sat Jan 30 19:25:18 2010	(r203220)
@@ -524,7 +524,7 @@ struct sysent sysent[] = {
 	{ AS(cpuset_getaffinity_args), (sy_call_t *)cpuset_getaffinity, AUE_NULL, NULL, 0, 0, 0 },	/* 487 = cpuset_getaffinity */
 	{ AS(cpuset_setaffinity_args), (sy_call_t *)cpuset_setaffinity, AUE_NULL, NULL, 0, 0, 0 },	/* 488 = cpuset_setaffinity */
 	{ AS(faccessat_args), (sy_call_t *)faccessat, AUE_FACCESSAT, NULL, 0, 0, SYF_CAPENABLED },	/* 489 = faccessat */
-	{ AS(fchmodat_args), (sy_call_t *)fchmodat, AUE_FCHMODAT, NULL, 0, 0, 0 },	/* 490 = fchmodat */
+	{ AS(fchmodat_args), (sy_call_t *)fchmodat, AUE_FCHMODAT, NULL, 0, 0, SYF_CAPENABLED },	/* 490 = fchmodat */
 	{ AS(fchownat_args), (sy_call_t *)fchownat, AUE_FCHOWNAT, NULL, 0, 0, 0 },	/* 491 = fchownat */
 	{ AS(fexecve_args), (sy_call_t *)fexecve, AUE_FEXECVE, NULL, 0, 0, SYF_CAPENABLED },	/* 492 = fexecve */
 	{ AS(fstatat_args), (sy_call_t *)fstatat, AUE_FSTATAT, NULL, 0, 0, 0 },	/* 493 = fstatat */

Modified: projects/capabilities8/sys/kern/vfs_syscalls.c
==============================================================================
--- projects/capabilities8/sys/kern/vfs_syscalls.c	Sat Jan 30 19:23:56 2010	(r203219)
+++ projects/capabilities8/sys/kern/vfs_syscalls.c	Sat Jan 30 19:25:18 2010	(r203220)
@@ -3042,13 +3042,20 @@ kern_fchmodat(struct thread *td, int fd,
 	struct nameidata nd;
 	int vfslocked;
 	int follow;
+	struct vnode *base;
 
 	AUDIT_ARG_MODE(mode);
 	follow = (flag & AT_SYMLINK_NOFOLLOW) ? NOFOLLOW : FOLLOW;
-	NDINIT_AT(&nd, LOOKUP,  follow | MPSAFE | AUDITVNODE1, pathseg, path,
-	    fd, td);
-	if ((error = namei(&nd)) != 0)
+	if ((error = fgetbase(td, fd, CAP_FCHMOD, &base)))
 		return (error);
+
+	NDINIT_ATBASE(&nd, LOOKUP,  follow | MPSAFE | AUDITVNODE1, pathseg, path,
+	    fd, base, td);
+	error = namei(&nd);
+	if (base) vput(base);
+	if (error)
+		return (error);
+
 	vfslocked = NDHASGIANT(&nd);
 	NDFREE(&nd, NDF_ONLY_PNBUF);
 	error = setfmode(td, nd.ni_vp, mode);