NetLabel: convert to an extensibile/sparse category bitmap

The original NetLabel category bitmap was a straight char bitmap which worked
fine for the initial release as it only supported 240 bits due to limitations
in the CIPSO restricted bitmap tag (tag type 0x01).  This patch converts that
straight char bitmap into an extensibile/sparse bitmap in order to lay the
foundation for other CIPSO tag types and protocols.

This patch also has a nice side effect in that all of the security attributes
passed by NetLabel into the LSM are now in a format which is in the host's
native byte/bit ordering which makes the LSM specific code much simpler; look
at the changes in security/selinux/ss/ebitmap.c as an example.

Signed-off-by: Paul Moore <paul.moore@hp.com>
Signed-off-by: James Morris <jmorris@namei.org>

1 files changed, 69 insertions, 99 deletions

diff --git a/net/ipv4/cipso_ipv4.c b/net/ipv4/cipso_ipv4.c
index f3957cf..08144f8 100644
--- a/net/ipv4/cipso_ipv4.c
+++ b/net/ipv4/cipso_ipv4.c
@@ -819,8 +819,7 @@ static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
 /**
  * cipso_v4_map_cat_rbm_hton - Perform a category mapping from host to network
  * @doi_def: the DOI definition
- * @host_cat: the category bitmap in host format
- * @host_cat_len: the length of the host's category bitmap in bytes
+ * @secattr: the security attributes
  * @net_cat: the zero'd out category bitmap in network/CIPSO format
  * @net_cat_len: the length of the CIPSO bitmap in bytes
  *
@@ -831,61 +830,51 @@ static int cipso_v4_map_cat_rbm_valid(const struct cipso_v4_doi *doi_def,
  *
  */
 static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
-				     const unsigned char *host_cat,
-				     u32 host_cat_len,
+				     const struct netlbl_lsm_secattr *secattr,
 				     unsigned char *net_cat,
 				     u32 net_cat_len)
 {
 	int host_spot = -1;
-	u32 net_spot;
+	u32 net_spot = CIPSO_V4_INV_CAT;
 	u32 net_spot_max = 0;
-	u32 host_clen_bits = host_cat_len * 8;
 	u32 net_clen_bits = net_cat_len * 8;
-	u32 host_cat_size;
-	u32 *host_cat_array;
+	u32 host_cat_size = 0;
+	u32 *host_cat_array = NULL;
 
-	switch (doi_def->type) {
-	case CIPSO_V4_MAP_PASS:
-		net_spot_max = host_cat_len;
-		while (net_spot_max > 0 && host_cat[net_spot_max - 1] == 0)
-			net_spot_max--;
-		if (net_spot_max > net_cat_len)
-			return -EINVAL;
-		memcpy(net_cat, host_cat, net_spot_max);
-		return net_spot_max;
-	case CIPSO_V4_MAP_STD:
+	if (doi_def->type == CIPSO_V4_MAP_STD) {
 		host_cat_size = doi_def->map.std->cat.local_size;
 		host_cat_array = doi_def->map.std->cat.local;
-		for (;;) {
-			host_spot = cipso_v4_bitmap_walk(host_cat,
-							 host_clen_bits,
-							 host_spot + 1,
-							 1);
-			if (host_spot < 0)
-				break;
+	}
+
+	for (;;) {
+		host_spot = netlbl_secattr_catmap_walk(secattr->mls_cat,
+						       host_spot + 1);
+		if (host_spot < 0)
+			break;
+
+		switch (doi_def->type) {
+		case CIPSO_V4_MAP_PASS:
+			net_spot = host_spot;
+			break;
+		case CIPSO_V4_MAP_STD:
 			if (host_spot >= host_cat_size)
 				return -EPERM;
-
 			net_spot = host_cat_array[host_spot];
 			if (net_spot >= CIPSO_V4_INV_CAT)
 				return -EPERM;
-			if (net_spot >= net_clen_bits)
-				return -ENOSPC;
-			cipso_v4_bitmap_setbit(net_cat, net_spot, 1);
-
-			if (net_spot > net_spot_max)
-				net_spot_max = net_spot;
+			break;
 		}
+		if (net_spot >= net_clen_bits)
+			return -ENOSPC;
+		cipso_v4_bitmap_setbit(net_cat, net_spot, 1);
 
-		if (host_spot == -2)
-			return -EFAULT;
-
-		if (++net_spot_max % 8)
-			return net_spot_max / 8 + 1;
-		return net_spot_max / 8;
+		if (net_spot > net_spot_max)
+			net_spot_max = net_spot;
 	}
 
-	return -EINVAL;
+	if (++net_spot_max % 8)
+		return net_spot_max / 8 + 1;
+	return net_spot_max / 8;
 }
 
 /**
@@ -893,66 +882,59 @@ static int cipso_v4_map_cat_rbm_hton(const struct cipso_v4_doi *doi_def,
  * @doi_def: the DOI definition
  * @net_cat: the category bitmap in network/CIPSO format
  * @net_cat_len: the length of the CIPSO bitmap in bytes
- * @host_cat: the zero'd out category bitmap in host format
- * @host_cat_len: the length of the host's category bitmap in bytes
+ * @secattr: the security attributes
  *
  * Description:
  * Perform a label mapping to translate a CIPSO bitmap to the correct local
- * MLS category bitmap using the given DOI definition.  Returns the minimum
- * size in bytes of the host bitmap on success, negative values otherwise.
+ * MLS category bitmap using the given DOI definition.  Returns zero on
+ * success, negative values on failure.
  *
  */
 static int cipso_v4_map_cat_rbm_ntoh(const struct cipso_v4_doi *doi_def,
 				     const unsigned char *net_cat,
 				     u32 net_cat_len,
-				     unsigned char *host_cat,
-				     u32 host_cat_len)
+				     struct netlbl_lsm_secattr *secattr)
 {
-	u32 host_spot;
-	u32 host_spot_max = 0;
+	int ret_val;
 	int net_spot = -1;
+	u32 host_spot = CIPSO_V4_INV_CAT;
 	u32 net_clen_bits = net_cat_len * 8;
-	u32 host_clen_bits = host_cat_len * 8;
-	u32 net_cat_size;
-	u32 *net_cat_array;
+	u32 net_cat_size = 0;
+	u32 *net_cat_array = NULL;
 
-	switch (doi_def->type) {
-	case CIPSO_V4_MAP_PASS:
-		if (net_cat_len > host_cat_len)
-			return -EINVAL;
-		memcpy(host_cat, net_cat, net_cat_len);
-		return net_cat_len;
-	case CIPSO_V4_MAP_STD:
+	if (doi_def->type == CIPSO_V4_MAP_STD) {
 		net_cat_size = doi_def->map.std->cat.cipso_size;
 		net_cat_array = doi_def->map.std->cat.cipso;
-		for (;;) {
-			net_spot = cipso_v4_bitmap_walk(net_cat,
-							net_clen_bits,
-							net_spot + 1,
-							1);
-			if (net_spot < 0)
-				break;
-			if (net_spot >= net_cat_size ||
-			    net_cat_array[net_spot] >= CIPSO_V4_INV_CAT)
-				return -EPERM;
+	}
 
+	for (;;) {
+		net_spot = cipso_v4_bitmap_walk(net_cat,
+						net_clen_bits,
+						net_spot + 1,
+						1);
+		if (net_spot < 0) {
+			if (net_spot == -2)
+				return -EFAULT;
+			return 0;
+		}
+
+		switch (doi_def->type) {
+		case CIPSO_V4_MAP_PASS:
+			host_spot = net_spot;
+			break;
+		case CIPSO_V4_MAP_STD:
+			if (net_spot >= net_cat_size)
+				return -EPERM;
 			host_spot = net_cat_array[net_spot];
 			if (host_spot >= CIPSO_V4_INV_CAT)
 				return -EPERM;
-			if (host_spot >= host_clen_bits)
-				return -ENOSPC;
-			cipso_v4_bitmap_setbit(host_cat, host_spot, 1);
-
-			if (host_spot > host_spot_max)
-				host_spot_max = host_spot;
+			break;
 		}
-
-		if (net_spot == -2)
-			return -EFAULT;
-
-		if (++host_spot_max % 8)
-			return host_spot_max / 8 + 1;
-		return host_spot_max / 8;
+		ret_val = netlbl_secattr_catmap_setbit(secattr->mls_cat,
+						       host_spot,
+						       GFP_ATOMIC);
+		if (ret_val != 0)
+			return ret_val;
 	}
 
 	return -EINVAL;
@@ -1016,8 +998,7 @@ static int cipso_v4_gentag_rbm(const struct cipso_v4_doi *doi_def,
 
 	if (secattr->flags & NETLBL_SECATTR_MLS_CAT) {
 		ret_val = cipso_v4_map_cat_rbm_hton(doi_def,
-						    secattr->mls_cat,
-						    secattr->mls_cat_len,
+						    secattr,
 						    &buffer[4],
 						    buffer_len - 4);
 		if (ret_val < 0)
@@ -1067,31 +1048,20 @@ static int cipso_v4_parsetag_rbm(const struct cipso_v4_doi *doi_def,
 	secattr->flags |= NETLBL_SECATTR_MLS_LVL;
 
 	if (tag_len > 4) {
-		switch (doi_def->type) {
-		case CIPSO_V4_MAP_PASS:
-			secattr->mls_cat_len = tag_len - 4;
-			break;
-		case CIPSO_V4_MAP_STD:
-			secattr->mls_cat_len =
-				doi_def->map.std->cat.local_size;
-			break;
-		}
-		secattr->mls_cat = kzalloc(secattr->mls_cat_len, GFP_ATOMIC);
+		secattr->mls_cat = netlbl_secattr_catmap_alloc(GFP_ATOMIC);
 		if (secattr->mls_cat == NULL)
 			return -ENOMEM;
 
 		ret_val = cipso_v4_map_cat_rbm_ntoh(doi_def,
 						    &tag[4],
 						    tag_len - 4,
-						    secattr->mls_cat,
-						    secattr->mls_cat_len);
-		if (ret_val < 0) {
-			kfree(secattr->mls_cat);
+						    secattr);
+		if (ret_val != 0) {
+			netlbl_secattr_catmap_free(secattr->mls_cat);
 			return ret_val;
-		} else if (ret_val > 0) {
-			secattr->mls_cat_len = ret_val;
-			secattr->flags |= NETLBL_SECATTR_MLS_CAT;
 		}
+
+		secattr->flags |= NETLBL_SECATTR_MLS_CAT;
 	}
 
 	return 0;