From 827e98884ff946f81179cc54d66e082e4f976a71 Mon Sep 17 00:00:00 2001
From: sam <sam@FreeBSD.org>
Date: Wed, 11 Mar 2009 01:12:52 +0000
Subject: [PATCH] o disallow write to RedBoot and FIS directory partitions;
 these are painful   to resurrect (maybe honor foot shooting bit in
 kern.geom_debugflags) o fix match macro so we now recognize we want to merge
 FIS dir with RedBoot   config parameters even if we don't actually do it

---
 sys/geom/geom_redboot.c | 25 +++++++++++++++++++++++--
 1 file changed, 23 insertions(+), 2 deletions(-)

diff --git a/sys/geom/geom_redboot.c b/sys/geom/geom_redboot.c
index 8ab89203d228..0314fe7c31aa 100644
--- a/sys/geom/geom_redboot.c
+++ b/sys/geom/geom_redboot.c
@@ -62,6 +62,7 @@ struct fis_image_desc {
 
 #define	FISDIR_NAME	"FIS directory"
 #define	REDBCFG_NAME	"RedBoot config"
+#define	REDBOOT_NAME	"RedBoot"
 
 #define	REDBOOT_MAXSLICE	64
 #define	REDBOOT_MAXOFF \
@@ -70,6 +71,8 @@ struct fis_image_desc {
 struct g_redboot_softc {
 	uint32_t	entry[REDBOOT_MAXSLICE];
 	uint32_t	dsize[REDBOOT_MAXSLICE];
+	uint8_t		readonly[REDBOOT_MAXSLICE];
+	g_access_t	*parent_access;
 };
 
 static void
@@ -89,6 +92,18 @@ g_redboot_ioctl(struct g_provider *pp, u_long cmd, void *data, int fflag, struct
 	return (ENOIOCTL);
 }
 
+static int
+g_redboot_access(struct g_provider *pp, int dread, int dwrite, int dexcl)
+{
+	struct g_geom *gp = pp->geom;
+	struct g_slicer *gsp = gp->softc;
+	struct g_redboot_softc *sc = gsp->softc;
+
+	if (dwrite > 0 && sc->readonly[pp->index])
+		return (EPERM);
+	return (sc->parent_access(pp, dread, dwrite, dexcl));
+}
+
 static int
 g_redboot_start(struct bio *bp)
 {
@@ -155,8 +170,7 @@ nameok(const char name[16])
 static struct fis_image_desc *
 parse_fis_directory(u_char *buf, size_t bufsize, off_t offset, uint32_t offmask)
 {
-#define	match(a,b) \
-	(bcmp(fd->name, FISDIR_NAME, sizeof(FISDIR_NAME)-1) == 0)
+#define	match(a,b)	(bcmp(a, b, sizeof(b)-1) == 0)
 	struct fis_image_desc *fd, *efd;
 	struct fis_image_desc *fisdir, *redbcfg;
 	struct fis_image_desc *head, **tail;
@@ -242,6 +256,10 @@ g_redboot_taste(struct g_class *mp, struct g_provider *pp, int insist)
 	    g_redboot_start);
 	if (gp == NULL)
 		return (NULL);
+	/* interpose our access method */
+	sc->parent_access = gp->access;
+	gp->access = g_redboot_access;
+
 	sectorsize = cp->provider->sectorsize;
 	blksize = cp->provider->stripesize;
 	if (powerof2(cp->provider->mediasize))
@@ -287,6 +305,9 @@ g_redboot_taste(struct g_class *mp, struct g_provider *pp, int insist)
 			    __func__, error, fd->name);
 		sc->entry[i] = fd->entry;
 		sc->dsize[i] = fd->dsize;
+		/* disallow writing hard-to-recover entries */
+		sc->readonly[i] = (strcmp(fd->name, FISDIR_NAME) == 0) ||
+				  (strcmp(fd->name, REDBOOT_NAME) == 0);
 		i++;
 	}
 	g_free(buf);