Author: mjg
Date: Wed Jul 18 04:52:37 2012
New Revision: 238560
URL: http://svn.freebsd.org/changeset/base/238560
Log:
MFC r238220, r238272:
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.
==
Follow-up commit to r238220:
Pass only FEXEC (instead of FREAD|FEXEC) in fgetvp_exec. _fget has to check
for
!FWRITE anyway and may as well know about FREAD.
Make _fget code a bit more readable by converting permission checking from
if()
to switch(). Assert that correct permission flags are passed.
PR: kern/169651
In collaboration with: kib
Approved by: re (hrs), trasz (mentor)
Modified:
stable/9/sys/kern/kern_descrip.c
stable/9/sys/kern/kern_exec.c
stable/9/sys/sys/file.h
Directory Properties:
stable/9/sys/ (props changed)
Modified: stable/9/sys/kern/kern_descrip.c
==============================================================================
--- stable/9/sys/kern/kern_descrip.c Tue Jul 17 22:16:10 2012
(r238559)
+++ stable/9/sys/kern/kern_descrip.c Wed Jul 18 04:52:37 2012
(r238560)
@@ -2329,8 +2329,8 @@ _fget(struct thread *td, int fd, struct
struct file *fp;
#ifdef CAPABILITIES
struct file *fp_fromcap;
- int error;
#endif
+ int error;
*fpp = NULL;
if (td == NULL || (fdp = td->td_proc->p_fd) == NULL)
@@ -2369,7 +2369,7 @@ _fget(struct thread *td, int fd, struct
else
error = cap_funwrap_mmap(fp, needrights, maxprotp,
&fp_fromcap);
- if (error) {
+ if (error != 0) {
fdrop(fp, td);
return (error);
}
@@ -2394,14 +2394,30 @@ _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)) {
+ error = 0;
+ switch (flags) {
+ case FREAD:
+ case FWRITE:
+ if ((fp->f_flag & flags) == 0)
+ error = EBADF;
+ break;
+ case FEXEC:
+ if ((fp->f_flag & (FREAD | FEXEC)) == 0 ||
+ ((fp->f_flag & FWRITE) != 0))
+ error = EBADF;
+ break;
+ case 0:
+ break;
+ default:
+ KASSERT(0, ("wrong flags"));
+ }
+
+ if (error != 0) {
fdrop(fp, td);
- return (EBADF);
+ return (error);
}
+
*fpp = fp;
return (0);
}
@@ -2498,6 +2514,13 @@ 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, FEXEC, rights, NULL, vpp));
+}
+
#ifdef notyet
int
fgetvp_write(struct thread *td, int fd, cap_rights_t rights,
Modified: stable/9/sys/kern/kern_exec.c
==============================================================================
--- stable/9/sys/kern/kern_exec.c Tue Jul 17 22:16:10 2012
(r238559)
+++ stable/9/sys/kern/kern_exec.c Wed Jul 18 04:52:37 2012
(r238560)
@@ -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: stable/9/sys/sys/file.h
==============================================================================
--- stable/9/sys/sys/file.h Tue Jul 17 22:16:10 2012 (r238559)
+++ stable/9/sys/sys/file.h Wed Jul 18 04:52:37 2012 (r238560)
@@ -225,6 +225,8 @@ 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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