git: 9front

Info  •  Files  •  Log  •  Branches

devshr: security!

--- a/sys/man/3/shr

+++ b/sys/man/3/shr

@@ -14,7 +14,9 @@

 The

 .I shr

 device provides global mountpoints in the form of share directories

-where 9p services can be mounted and unmounted dynamically.

+where

+.IR 9P

+services can be mounted on.

 Effectively, it is a global mountpoint registry that is separate from

 private namespaces.

@@ -26,7 +28,7 @@

 .BI #σ

 are the share mountpoints themselve and in the control tree

 .BI #σc

-share directories can be created or removed.

+share directories list the service files of the share.

 .PP

 To create a new share, create the directory

 .B #σc/myshare

@@ -37,13 +39,26 @@

 .IR strtoul ;

 see

 .IR atof (2))

-giving the file descriptor number of an open 9p service.  Any process

+giving the file descriptor number of an open

+.I 9P

+service.  Any process

 with the proper permission may then access

 .B #σ/myshare

-to use the service.

+on the mount tree.

 .PP

-Multiple services can be mounted under a share.  New services get

-mounted before old ones.  Removing the service file from a share

-removes the service as soon as the last reference goes away.

+The service file can be reopened and passed to

+.IR mount

+(see

+.IR bind(2))

+or added to another share.

+.PP

+Multiple services can be mounted under a share forming a union

+directory. New services get mounted before old ones.

+Removing the service file unmounts the service from the share.

+.PP

+Creating shares and mounts requires read-write access in the share

+directory. The special user

+.B none

+is prohibited from these operations.

 .SH SOURCE

 .B /sys/src/9/port/devshr.c

--- a/sys/src/9/boot/nusbrc

+++ b/sys/src/9/boot/nusbrc

@@ -2,7 +2,7 @@

 if(! bind -a '#u' /dev)

 	exit

-mkdir '#σc/usb'

+mkdir -m 0700 '#σc/usb'

 if(! nusb/usbd)

 	exit

--- a/sys/src/9/port/devshr.c

+++ b/sys/src/9/port/devshr.c

@@ -392,6 +392,8 @@

 		devpermcheck(shr->owner, shr->perm, openmode(omode));

 		break;

 	case Qcmpt:

+		if(omode&OTRUNC)

+			error(Eexist);

 		shr = sch->shr;

 		mpt = sch->mpt;

 		devpermcheck(mpt->owner, mpt->perm, openmode(omode));

@@ -430,6 +432,12 @@

 	default:

 		error(Enocreate);

 	case Qcroot:

+	case Qcshr:

+		if(strcmp(up->user, "none") == 0)

+			error(Eperm);

+	}

+	switch(sch->level){

+	case Qcroot:

 		if((perm & DMDIR) == 0 || openmode(omode) != OREAD)

 			error(Eperm);

@@ -461,11 +469,14 @@

 		sch->shr = shr;

 		break;

 	case Qcshr:

-		shr = sch->shr;

-		devpermcheck(shr->owner, shr->perm, ORDWR);

 		if((perm & DMDIR) || openmode(omode) != OWRITE)

 			error(Eperm);

+		shr = sch->shr;

+		if(strcmp(shr->owner, eve) == 0 && !iseve())

+			error(Eperm);

+		devpermcheck(shr->owner, shr->perm, ORDWR);

+

 		h = &shr->umh;

 		wlock(&h->lock);

 		if(waserror()){

@@ -520,8 +531,16 @@

 	default:

 		error(Eperm);

 	case Qcshr:

+	case Qcmpt:

 		shr = sch->shr;

-		devpermcheck(shr->owner, shr->perm, ORDWR);

+		if(!iseve()){

+			if(strcmp(shr->owner, eve) == 0)

+				error(Eperm);

+			devpermcheck(shr->owner, shr->perm, ORDWR);

+		}

+	}

+	switch(sch->level){

+	case Qcshr:

 		h = &shr->umh;

 		qlock(&shrslk);

 		rlock(&h->lock);

@@ -541,8 +560,6 @@

 		qunlock(&shrslk);

 		break;

 	case Qcmpt:

-		shr = sch->shr;

-		devpermcheck(shr->owner, shr->perm, ORDWR);

 		mpt = sch->mpt;

 		m = &mpt->m;

 		h = &shr->umh;

@@ -630,7 +647,6 @@

 		wunlock(&h->lock);

 		break;

 	}

-

 	return n;

 }

-- 

⑨