Second-to-last commit implementing Capsicum capabilities in the FreeBSD

kernel for FreeBSD 9.0:

Add a new capability mask argument to fget(9) and friends, allowing system
call code to declare what capabilities are required when an integer file
descriptor is converted into an in-kernel struct file *.  With options
CAPABILITIES compiled into the kernel, this enforces capability
protection; without, this change is effectively a no-op.

Some cases require special handling, such as mmap(2), which must preserve
information about the maximum rights at the time of mapping in the memory
map so that they can later be enforced in mprotect(2) -- this is done by
narrowing the rights in the existing max_protection field used for similar
purposes with file permissions.

In namei(9), we assert that the code is not reached from within capability
mode, as we're not yet ready to enforce namespace capabilities there.
This will follow in a later commit.

Update two capability names: CAP_EVENT and CAP_KEVENT become
CAP_POST_KEVENT and CAP_POLL_KEVENT to more accurately indicate what they
represent.

Approved by:	re (bz)
Submitted by:	jonathan
Sponsored by:	Google Inc

8 files changed, 18 insertions, 8 deletions

diff --git a/sys/dev/aac/aac_linux.c b/sys/dev/aac/aac_linux.c
index f885235..049e2be 100644
--- a/sys/dev/aac/aac_linux.c
+++ b/sys/dev/aac/aac_linux.c
@@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/capability.h>
 #include <sys/conf.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
@@ -78,7 +79,7 @@ aac_linux_ioctl(struct thread *td, struct linux_ioctl_args *args)
 	u_long cmd;
 	int error;
 
-	if ((error = fget(td, args->fd, &fp)) != 0)
+	if ((error = fget(td, args->fd, CAP_IOCTL, &fp)) != 0)
 		return (error);
 	cmd = args->cmd;
 
diff --git a/sys/dev/amr/amr_linux.c b/sys/dev/amr/amr_linux.c
index cb8c457..44e858b 100644
--- a/sys/dev/amr/amr_linux.c
+++ b/sys/dev/amr/amr_linux.c
@@ -30,6 +30,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/capability.h>
 #include <sys/conf.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
@@ -74,7 +75,7 @@ amr_linux_ioctl(struct thread *p, struct linux_ioctl_args *args)
 	struct file *fp;
 	int error;
 
-	if ((error = fget(p, args->fd, &fp)) != 0)
+	if ((error = fget(p, args->fd, CAP_IOCTL, &fp)) != 0)
 		return (error);
 	error = fo_ioctl(fp, args->cmd, (caddr_t)args->arg, p->td_ucred, p);
 	fdrop(fp, p);
diff --git a/sys/dev/hwpmc/hwpmc_logging.c b/sys/dev/hwpmc/hwpmc_logging.c
index 633c6f9..b85572a 100644
--- a/sys/dev/hwpmc/hwpmc_logging.c
+++ b/sys/dev/hwpmc/hwpmc_logging.c
@@ -37,6 +37,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/capability.h>
 #include <sys/file.h>
 #include <sys/kernel.h>
 #include <sys/kthread.h>
@@ -589,7 +590,7 @@ pmclog_configure_log(struct pmc_mdep *md, struct pmc_owner *po, int logfd)
 		po->po_file));
 
 	/* get a reference to the file state */
-	error = fget_write(curthread, logfd, &po->po_file);
+	error = fget_write(curthread, logfd, CAP_WRITE, &po->po_file);
 	if (error)
 		goto error;
 
diff --git a/sys/dev/ipmi/ipmi_linux.c b/sys/dev/ipmi/ipmi_linux.c
index fcf2bd5..430bd08 100644
--- a/sys/dev/ipmi/ipmi_linux.c
+++ b/sys/dev/ipmi/ipmi_linux.c
@@ -33,6 +33,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/capability.h>
 #include <sys/conf.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
@@ -92,7 +93,7 @@ ipmi_linux_ioctl(struct thread *td, struct linux_ioctl_args *args)
 	u_long cmd;
 	int error;
 
-	if ((error = fget(td, args->fd, &fp)) != 0)
+	if ((error = fget(td, args->fd, CAP_IOCTL, &fp)) != 0)
 		return (error);
 	cmd = args->cmd;
 
diff --git a/sys/dev/iscsi/initiator/iscsi.c b/sys/dev/iscsi/initiator/iscsi.c
index d35f631..292ce8f 100644
--- a/sys/dev/iscsi/initiator/iscsi.c
+++ b/sys/dev/iscsi/initiator/iscsi.c
@@ -34,6 +34,7 @@ __FBSDID("$FreeBSD$");
 #include "opt_iscsi_initiator.h"
 
 #include <sys/param.h>
+#include <sys/capability.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
 #include <sys/conf.h>
@@ -387,11 +388,11 @@ i_setsoc(isc_session_t *sp, int fd, struct thread *td)
      if(sp->soc != NULL)
 	  isc_stop_receiver(sp);
 
-     error = fget(td, fd, &sp->fp);
+     error = fget(td, fd, CAP_SOCK_ALL, &sp->fp);
      if(error)
 	  return error;
 
-     if((error = fgetsock(td, fd, &sp->soc, 0)) == 0) {
+     if((error = fgetsock(td, fd, CAP_SOCK_ALL, &sp->soc, 0)) == 0) {
 	  sp->td = td;
 	  isc_start_receiver(sp);
      }
diff --git a/sys/dev/mfi/mfi_linux.c b/sys/dev/mfi/mfi_linux.c
index 44edf49..12135ff 100644
--- a/sys/dev/mfi/mfi_linux.c
+++ b/sys/dev/mfi/mfi_linux.c
@@ -29,6 +29,7 @@ __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
 #include <sys/systm.h>
+#include <sys/capability.h>
 #include <sys/conf.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
@@ -95,7 +96,7 @@ mfi_linux_ioctl(struct thread *p, struct linux_ioctl_args *args)
 		break;
 	}
 
-	if ((error = fget(p, args->fd, &fp)) != 0)
+	if ((error = fget(p, args->fd, CAP_IOCTL, &fp)) != 0)
 		return (error);
 	error = fo_ioctl(fp, cmd, (caddr_t)args->arg, p->td_ucred, p);
 	fdrop(fp, p);
diff --git a/sys/dev/snp/snp.c b/sys/dev/snp/snp.c
index b05ad2a..1c02660 100644
--- a/sys/dev/snp/snp.c
+++ b/sys/dev/snp/snp.c
@@ -252,6 +252,9 @@ snp_ioctl(struct cdev *dev, u_long cmd, caddr_t data, int flags,
 			SNP_UNLOCK();
 			return (EBUSY);
 		}
+		/*
+		 * XXXRW / XXXJA: no capability check here.
+		 */
 		error = ttyhook_register(&ss->snp_tty, td->td_proc,
 		    *(int *)data, &snp_hook, ss);
 		SNP_UNLOCK();
diff --git a/sys/dev/tdfx/tdfx_linux.c b/sys/dev/tdfx/tdfx_linux.c
index 2e877f6..0b769f0 100644
--- a/sys/dev/tdfx/tdfx_linux.c
+++ b/sys/dev/tdfx/tdfx_linux.c
@@ -28,6 +28,7 @@
 __FBSDID("$FreeBSD$");
 
 #include <sys/param.h>
+#include <sys/capability.h>
 #include <sys/file.h>
 #include <sys/kernel.h>
 #include <sys/module.h>
@@ -53,7 +54,7 @@ linux_ioctl_tdfx(struct thread *td, struct linux_ioctl_args* args)
 
    struct file *fp;
 
-   if ((error = fget(td, args->fd, &fp)) != 0)
+   if ((error = fget(td, args->fd, CAP_IOCTL, &fp)) != 0)
 	   return (error);
    /* We simply copy the data and send it right to ioctl */
    copyin((caddr_t)args->arg, &d_pio, sizeof(d_pio));