Don't try to spoof 0 length DOS MBR/EBR partitions. By skipping

partitions with 0 in the length field we don't need to test for
and skip partitions that are all zeros. Eliminating that code
allows elimination of a local pointer.

"0 length partitions are definately dead" deraadt@

11 files changed, 66 insertions, 165 deletions

diff --git a/sys/arch/alpha/alpha/disksubr.c b/sys/arch/alpha/alpha/disksubr.c
index ad25008c37f..d15e4613535 100644
--- a/sys/arch/alpha/alpha/disksubr.c
+++ b/sys/arch/alpha/alpha/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.62 2006/10/21 16:01:53 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.63 2006/10/21 20:10:39 krw Exp $	*/
 /*	$NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $	*/
 
 /*
@@ -222,7 +222,7 @@ readdoslabel(bp, strat, lp, osdep, partoffp, cylp, spoofonly)
 	struct partition *pp;
 	unsigned long extoff = 0;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -307,25 +307,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/amd64/amd64/disksubr.c b/sys/arch/amd64/amd64/disksubr.c
index ec839393506..dbc07be3e80 100644
--- a/sys/arch/amd64/amd64/disksubr.c
+++ b/sys/arch/amd64/amd64/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.23 2006/10/21 16:01:53 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.24 2006/10/21 20:10:39 krw Exp $	*/
 /*	$NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $	*/
 
 /*
@@ -73,7 +73,7 @@ readdisklabel(dev, strat, lp, osdep, spoofonly)
 	unsigned long extoff = 0;
 	struct buf *bp = NULL;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -166,25 +166,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/arm/arm/disksubr.c b/sys/arch/arm/arm/disksubr.c
index 7e3ffe505a3..7aa73a25b29 100644
--- a/sys/arch/arm/arm/disksubr.c
+++ b/sys/arch/arm/arm/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.21 2006/10/21 16:01:53 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.22 2006/10/21 20:10:39 krw Exp $	*/
 /*	$NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $	*/
 
 /*
@@ -73,7 +73,7 @@ readdisklabel(dev, strat, lp, osdep, spoofonly)
 	unsigned long extoff = 0;
 	struct buf *bp = NULL;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -166,25 +166,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/aviion/aviion/disksubr.c b/sys/arch/aviion/aviion/disksubr.c
index 6e6f74fe9c8..4ce153e11c5 100644
--- a/sys/arch/aviion/aviion/disksubr.c
+++ b/sys/arch/aviion/aviion/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.12 2006/10/21 16:01:53 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.13 2006/10/21 20:10:39 krw Exp $	*/
 /*	$NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $	*/
 
 /*
@@ -73,7 +73,7 @@ readdisklabel(dev, strat, lp, osdep, spoofonly)
 	unsigned long extoff = 0;
 	struct buf *bp = NULL;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -166,25 +166,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/hppa/hppa/disksubr.c b/sys/arch/hppa/hppa/disksubr.c
index 14dd7cdc355..df031b5167f 100644
--- a/sys/arch/hppa/hppa/disksubr.c
+++ b/sys/arch/hppa/hppa/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.42 2006/10/21 16:01:53 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.43 2006/10/21 20:10:39 krw Exp $	*/
 
 /*
  * Copyright (c) 1999 Michael Shalayeff
@@ -225,7 +225,7 @@ readdoslabel(bp, strat, lp, osdep, partoffp, cylp, spoofonly)
 	struct partition *pp;
 	unsigned long extoff = 0;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -310,25 +310,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/hppa64/hppa64/disksubr.c b/sys/arch/hppa64/hppa64/disksubr.c
index 3366bdbefd5..95501371a51 100644
--- a/sys/arch/hppa64/hppa64/disksubr.c
+++ b/sys/arch/hppa64/hppa64/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.25 2006/10/21 16:01:54 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.26 2006/10/21 20:10:39 krw Exp $	*/
 
 /*
  * Copyright (c) 1999 Michael Shalayeff
@@ -221,7 +221,7 @@ readdoslabel(bp, strat, lp, osdep, partoffp, cylp, spoofonly)
 	struct partition *pp;
 	unsigned long extoff = 0;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -306,25 +306,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/i386/i386/disksubr.c b/sys/arch/i386/i386/disksubr.c
index 2d6bf5beab9..c74021103a7 100644
--- a/sys/arch/i386/i386/disksubr.c
+++ b/sys/arch/i386/i386/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.65 2006/10/21 16:01:54 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.66 2006/10/21 20:10:39 krw Exp $	*/
 /*	$NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $	*/
 
 /*
@@ -69,7 +69,7 @@ readdisklabel(dev_t dev, void (*strat)(struct buf *), struct disklabel *lp,
 	unsigned long extoff = 0;
 	struct buf *bp = NULL;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -162,25 +162,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/landisk/landisk/disksubr.c b/sys/arch/landisk/landisk/disksubr.c
index a1667b767b8..ddf101269f2 100644
--- a/sys/arch/landisk/landisk/disksubr.c
+++ b/sys/arch/landisk/landisk/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.9 2006/10/21 16:01:54 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.10 2006/10/21 20:10:39 krw Exp $	*/
 /*	$NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $	*/
 
 /*
@@ -73,7 +73,7 @@ readdisklabel(dev, strat, lp, osdep, spoofonly)
 	unsigned long extoff = 0;
 	struct buf *bp = NULL;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -166,25 +166,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/macppc/macppc/disksubr.c b/sys/arch/macppc/macppc/disksubr.c
index 2b84644dd97..1def3fb4cce 100644
--- a/sys/arch/macppc/macppc/disksubr.c
+++ b/sys/arch/macppc/macppc/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.31 2006/10/21 16:01:54 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.32 2006/10/21 20:10:39 krw Exp $	*/
 /*	$NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $	*/
 
 /*
@@ -72,7 +72,7 @@ readdisklabel(dev_t dev, void (*strat)(struct buf *),
 	unsigned long extoff = 0;
 	struct buf *bp;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	char *s;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, loop = 0;
@@ -252,25 +252,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/mips64/mips64/disksubr.c b/sys/arch/mips64/mips64/disksubr.c
index a941842d14d..5d75837567b 100644
--- a/sys/arch/mips64/mips64/disksubr.c
+++ b/sys/arch/mips64/mips64/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.31 2006/10/21 16:01:54 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.32 2006/10/21 20:10:39 krw Exp $	*/
 
 /*
  * Copyright (c) 1999 Michael Shalayeff
@@ -229,7 +229,7 @@ readdoslabel(bp, strat, lp, osdep, partoffp, cylp, spoofonly)
 	struct partition *pp;
 	unsigned long extoff = 0;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -314,25 +314,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;
diff --git a/sys/arch/mvmeppc/mvmeppc/disksubr.c b/sys/arch/mvmeppc/mvmeppc/disksubr.c
index cda3da49b56..9cfd38a004a 100644
--- a/sys/arch/mvmeppc/mvmeppc/disksubr.c
+++ b/sys/arch/mvmeppc/mvmeppc/disksubr.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: disksubr.c,v 1.27 2006/10/21 16:01:54 krw Exp $	*/
+/*	$OpenBSD: disksubr.c,v 1.28 2006/10/21 20:10:39 krw Exp $	*/
 /*	$NetBSD: disksubr.c,v 1.21 1996/05/03 19:42:03 christos Exp $	*/
 
 /*
@@ -76,7 +76,7 @@ readdisklabel(dev, strat, lp, osdep, spoofonly)
 	unsigned long extoff = 0;
 	struct buf *bp;
 	daddr_t part_blkno = DOSBBSECTOR;
-	char *msg = NULL, *cp;
+	char *msg = NULL;
 	int dospartoff, cyl, i, ourpart = -1;
 	int wander = 1, n = 0, loop = 0;
 
@@ -169,25 +169,16 @@ donot:
 				continue;
 			if (letoh32(dp2->dp_size) > lp->d_secperunit)
 				continue;
-			if (letoh32(dp2->dp_size))
-				pp->p_size = letoh32(dp2->dp_size);
+			if (letoh32(dp2->dp_size) == 0)
+				continue;
 			if (letoh32(dp2->dp_start))
 				pp->p_offset =
 				    letoh32(dp2->dp_start) + part_blkno;
 
+			pp->p_size = letoh32(dp2->dp_size);
+
 			switch (dp2->dp_typ) {
 			case DOSPTYP_UNUSED:
-				for (cp = (char *)dp2;
-				    cp < (char *)(dp2 + 1); cp++)
-					if (*cp)
-						break;
-				/*
-				 * Was it all zeroes?  If so, it is
-				 * an unused entry that we don't
-				 * want to show.
-				 */
-				if (cp == (char *)(dp2 + 1))
-				    continue;
 				pp->p_fstype = FS_UNUSED;
 				n++;
 				break;