Differential D2808 Diff 18847 sys/kern/vfs_syscalls.c

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sys/kern/vfs_syscalls.c

Show First 20 Lines • Show All 951 Lines • ▼ Show 20 Lines	kern_openat(struct thread td, int fd, char path, enum uio_seg pathseg,
int flags, int mode)		int flags, int mode)
{		{
struct proc *p = td->td_proc;		struct proc *p = td->td_proc;
struct filedesc *fdp = p->p_fd;		struct filedesc *fdp = p->p_fd;
struct file *fp;		struct file *fp;
struct vnode *vp;		struct vnode *vp;
struct nameidata nd;		struct nameidata nd;
cap_rights_t rights;		cap_rights_t rights;
int cmode, error, indx;		int beneath, cmode, error, indx;

indx = -1;		indx = -1;

AUDIT_ARG_FFLAGS(flags);		AUDIT_ARG_FFLAGS(flags);
AUDIT_ARG_MODE(mode);		AUDIT_ARG_MODE(mode);
cap_rights_init(&rights, CAP_LOOKUP);		cap_rights_init(&rights, CAP_LOOKUP);
flags_to_rights(flags, &rights);		flags_to_rights(flags, &rights);
		beneath = ((flags & O_BENEATH) == O_BENEATH);
/*		/*
* Only one of the O_EXEC, O_RDONLY, O_WRONLY and O_RDWR flags		* Only one of the O_EXEC, O_RDONLY, O_WRONLY and O_RDWR flags
* may be specified.		* may be specified.
*/		*/
if (flags & O_EXEC) {		if (flags & O_EXEC) {
if (flags & O_ACCMODE)		if (flags & O_ACCMODE)
return (EINVAL);		return (EINVAL);
} else if ((flags & O_ACCMODE) == O_ACCMODE) {		} else if ((flags & O_ACCMODE) == O_ACCMODE) {
return (EINVAL);		return (EINVAL);
} else {		} else {
flags = FFLAGS(flags);		flags = FFLAGS(flags);
}		}
		drysdale_google.comUnsubmitted Done Inline Actions (Random aside: does FreeBSD not attempt to police unrecognized flags? In Linux, syscalls are (now) recommended to reject unknown flags with EINVAL.) drysdale_google.com: (Random aside: does FreeBSD not attempt to police unrecognized flags? In Linux, syscalls are…
		jonathanAuthorUnsubmitted Done Inline Actions This strikes me as a fundamentally good idea, but others may disagree for compatibility reasons... maybe worth talking about for 11, but probably not in this hopefully-MFC'able change. jonathan: This strikes me as a fundamentally good idea, but others may disagree for compatibility reasons.
		rwatsonUnsubmitted Done Inline Actions I think validating flags is a good idea -- but agree that it might be done on a different MFC schedule and hence should be a separate change. rwatson: I think validating flags is a good idea -- but agree that it might be done on a different MFC…

/*		/*
* Allocate a file structure. The descriptor to reference it		* Allocate a file structure. The descriptor to reference it
* is allocated and set by finstall() below.		* is allocated and set by finstall() below.
*/		*/
error = falloc_noinstall(td, &fp);		error = falloc_noinstall(td, &fp);
if (error != 0)		if (error != 0)
return (error);		return (error);
/*		/*
* An extra reference on `fp' has been held for us by		* An extra reference on `fp' has been held for us by
* falloc_noinstall().		* falloc_noinstall().
*/		*/
/* Set the flags early so the finit in devfs can pick them up. */		/* Set the flags early so the finit in devfs can pick them up. */
fp->f_flag = flags & FMASK;		fp->f_flag = flags & FMASK;
cmode = ((mode & ~fdp->fd_cmask) & ALLPERMS) & ~S_ISTXT;		cmode = ((mode & ~fdp->fd_cmask) & ALLPERMS) & ~S_ISTXT;
NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW \| AUDITVNODE1, pathseg, path, fd,		NDINIT_ATRIGHTS(&nd, LOOKUP, FOLLOW \| AUDITVNODE1, pathseg, path, fd,
&rights, td);		&rights, td);
		if (beneath)
		nd.ni_nonrelativeerrno = EPERM;
td->td_dupfd = -1; /* XXX check for fdopen */		td->td_dupfd = -1; /* XXX check for fdopen */
		emasteUnsubmitted Done Inline Actions Extra braces emaste: Extra braces
		jonathanAuthorUnsubmitted Done Inline Actions Ok, I will change this conform to `style(9)`, but I officially protest that I do so under duress. :) From now on, I will refer to this paragraph of `style(9)` as the "goto fail" paragraph. jonathan: Ok, I will change this conform to `style(9)`, but I officially protest that I do so under…
error = vn_open(&nd, &flags, cmode, fp);		error = vn_open(&nd, &flags, cmode, fp);
if (error != 0) {		if (error != 0) {
/*		/*
* If the vn_open replaced the method vector, something		* If the vn_open replaced the method vector, something
* wonderous happened deep below and we just pass it up		* wonderous happened deep below and we just pass it up
* pretending we know what we do.		* pretending we know what we do.
*/		*/
if (error == ENXIO && fp->f_ops != &badfileops)		if (error == ENXIO && fp->f_ops != &badfileops)
goto success;		goto success;

/*		/*
* Handle special fdopen() case. bleh.		* Handle special fdopen() case. bleh.
*		*
* Don't do this for relative (capability) lookups; we don't		* Don't do this for capability or O_BENEATH lookups: we don't
* understand exactly what would happen, and we don't think		* understand exactly what would happen, and we don't think
* that it ever should.		* that it ever should.
		*
		* XXXJA: can fdopen() ever be called with O_BENEATH?
		rwatsonUnsubmitted Done Inline Actions Hmm. I think failing closed here is reasonable for capability mode -- but I'm not sure if that's true for ambient O_BENEATH. I believe td_dupfd is set for /dev/fd/[012] and /dev/{stderr,stdin,stdout}, which might reasonable be expected to work outside of capability mode. It also looks like it's used in another edge case or two (sysvr4 compatibility!?). rwatson: Hmm. I think failing closed here is reasonable for capability mode -- but I'm not sure if…
		jonathanAuthorUnsubmitted Done Inline Actions Since we've said that `O_BENEATH`supercedes the capability rules (in the sense that we want the `O_BENEATH` errno whether we're in or out of capability mode), we can't know at this point whether the original file was a capability: we just see `EPERM`. If this code is related to `fdopen()`, I don't anticipate `O_BENEATH` being used much... jonathan: Since we've said that `O_BENEATH`supercedes the capability rules (in the sense that we want the…
		rwatsonUnsubmitted Done Inline Actions Maybe make this an XXXCAP or XXXJA or such, but otherwise, yes, I agree. We'll see if anyone ever runs into it! rwatson: Maybe make this an XXXCAP or XXXJA or such, but otherwise, yes, I agree. We'll see if anyone…
		jonathanAuthorUnsubmitted Done Inline Actions Adding more `XXX` here sounds like a fine thing to do. :) jonathan: Adding more `XXX` here sounds like a fine thing to do. :)
*/		*/
if (nd.ni_strictrelative == 0 &&		if (nd.ni_nonrelativeerrno == 0 &&
(error == ENODEV \|\| error == ENXIO) &&		(error == ENODEV \|\| error == ENXIO) &&
td->td_dupfd >= 0) {		td->td_dupfd >= 0) {
error = dupfdopen(td, fdp, td->td_dupfd, flags, error,		error = dupfdopen(td, fdp, td->td_dupfd, flags, error,
&indx);		&indx);
if (error == 0)		if (error == 0)
goto success;		goto success;
}		}

Show All 29 Lines
success:		success:
/*		/*
* If we haven't already installed the FD (for dupfdopen), do so now.		* If we haven't already installed the FD (for dupfdopen), do so now.
*/		*/
if (indx == -1) {		if (indx == -1) {
struct filecaps *fcaps;		struct filecaps *fcaps;

#ifdef CAPABILITIES		#ifdef CAPABILITIES
if (nd.ni_strictrelative == 1)		if (nd.ni_nonrelativeerrno != 0 &&
		cap_rights_is_valid(&nd.ni_filecaps.fc_rights))
fcaps = &nd.ni_filecaps;		fcaps = &nd.ni_filecaps;
else		else
#endif		#endif
fcaps = NULL;		fcaps = NULL;
error = finstall(td, fp, &indx, flags, fcaps);		error = finstall(td, fp, &indx, flags, fcaps);
/* On success finstall() consumes fcaps. */		/* On success finstall() consumes fcaps. */
if (error != 0) {		if (error != 0) {
filecaps_free(&nd.ni_filecaps);		filecaps_free(&nd.ni_filecaps);
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