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Date:      Sun, 8 Jul 2012 00:51:38 +0000 (UTC)
From:      Mateusz Guzik <mjg@FreeBSD.org>
To:        src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   svn commit: r238220 - in head/sys: kern sys
Message-ID:  <201207080051.q680pcYO005980@svn.freebsd.org>
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Author: mjg
Date: Sun Jul  8 00:51:38 2012
New Revision: 238220
URL: http://svn.freebsd.org/changeset/base/238220

Log:
  Unbreak handling of descriptors opened with O_EXEC by fexecve(2).
  
  While here return EBADF for descriptors opened for writing (previously it was ETXTBSY).
  
  Add fgetvp_exec function which performs appropriate checks.
  
  PR:		kern/169651
  In collaboration with:	kib
  Approved by:	trasz (mentor)
  MFC after:	1 week

Modified:
  head/sys/kern/kern_descrip.c
  head/sys/kern/kern_exec.c
  head/sys/sys/file.h

Modified: head/sys/kern/kern_descrip.c
==============================================================================
--- head/sys/kern/kern_descrip.c	Sat Jul  7 22:22:13 2012	(r238219)
+++ head/sys/kern/kern_descrip.c	Sun Jul  8 00:51:38 2012	(r238220)
@@ -2340,11 +2340,11 @@ _fget(struct thread *td, int fd, struct 
 
 	/*
 	 * FREAD and FWRITE failure return EBADF as per POSIX.
-	 *
-	 * Only one flag, or 0, may be specified.
 	 */
 	if ((flags == FREAD && (fp->f_flag & FREAD) == 0) ||
-	    (flags == FWRITE && (fp->f_flag & FWRITE) == 0)) {
+	    (flags == FWRITE && (fp->f_flag & FWRITE) == 0) ||
+	    (flags == (FREAD | FEXEC) &&
+	    (((fp->f_flag & flags) == 0) || ((fp->f_flag & FWRITE) != 0)))) {
 		fdrop(fp, td);
 		return (EBADF);
 	}
@@ -2444,6 +2444,13 @@ fgetvp_read(struct thread *td, int fd, c
 	return (_fgetvp(td, fd, FREAD, rights, NULL, vpp));
 }
 
+int
+fgetvp_exec(struct thread *td, int fd, cap_rights_t rights, struct vnode **vpp)
+{
+
+	return (_fgetvp(td, fd, FREAD | FEXEC, rights, NULL, vpp));
+}
+
 #ifdef notyet
 int
 fgetvp_write(struct thread *td, int fd, cap_rights_t rights,

Modified: head/sys/kern/kern_exec.c
==============================================================================
--- head/sys/kern/kern_exec.c	Sat Jul  7 22:22:13 2012	(r238219)
+++ head/sys/kern/kern_exec.c	Sun Jul  8 00:51:38 2012	(r238220)
@@ -443,8 +443,10 @@ interpret:
 		/*
 		 * Some might argue that CAP_READ and/or CAP_MMAP should also
 		 * be required here; such arguments will be entertained.
+		 *
+		 * Descriptors opened only with O_EXEC or O_RDONLY are allowed.
 		 */
-		error = fgetvp_read(td, args->fd, CAP_FEXECVE, &binvp);
+		error = fgetvp_exec(td, args->fd, CAP_FEXECVE, &binvp);
 		if (error)
 			goto exec_fail;
 		vfslocked = VFS_LOCK_GIANT(binvp->v_mount);

Modified: head/sys/sys/file.h
==============================================================================
--- head/sys/sys/file.h	Sat Jul  7 22:22:13 2012	(r238219)
+++ head/sys/sys/file.h	Sun Jul  8 00:51:38 2012	(r238220)
@@ -238,6 +238,8 @@ fo_chown_t	invfo_chown;
 
 void finit(struct file *, u_int, short, void *, struct fileops *);
 int fgetvp(struct thread *td, int fd, cap_rights_t rights, struct vnode **vpp);
+int fgetvp_exec(struct thread *td, int fd, cap_rights_t rights,
+    struct vnode **vpp);
 int fgetvp_rights(struct thread *td, int fd, cap_rights_t need,
     cap_rights_t *have, struct vnode **vpp);
 int fgetvp_read(struct thread *td, int fd, cap_rights_t rights,

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