[PATCH] selinux: fix byte order and alignment issues in policydb.c

[Ondrej Mosnacek <omosnace@xxxxxxxxxx>]

Add missing LE conversions to the Infiniband-related range checks. These
were causing a failure to load any policy with an ibendportcon rule on
BE systems.

Also, the temporary buffers are only guaranteed to be aligned for 32-bit
access so use (get/put)_unaligned_be64() for 64-bit accesses.

Finally, do not use the 'nodebuf' (u32) buffer where 'buf' (__le32)
should be used instead.

Tested internally on a ppc64 machine with a RHEL 7 kernel with this
patch applied.

Cc: Daniel Jurgens <danielj@xxxxxxxxxxxx>
Cc: Eli Cohen <eli@xxxxxxxxxxxx>
Cc: James Morris <james.l.morris@xxxxxxxxxx>
Cc: Doug Ledford <dledford@xxxxxxxxxx>
Cc: <stable@xxxxxxxxxxxxxxx> # 4.13+
Fixes: a806f7a1616f ("selinux: Create policydb version for Infiniband support")
Signed-off-by: Ondrej Mosnacek <omosnace@xxxxxxxxxx>
---
 security/selinux/ss/policydb.c | 28 +++++++++++++++-------------
 1 file changed, 15 insertions(+), 13 deletions(-)

diff --git a/security/selinux/ss/policydb.c b/security/selinux/ss/policydb.c
index f4eadd3f7350..2b310e8f2923 100644
--- a/security/selinux/ss/policydb.c
+++ b/security/selinux/ss/policydb.c
@@ -37,6 +37,7 @@
 #include <linux/errno.h>
 #include <linux/audit.h>
 #include <linux/flex_array.h>
+#include <asm/unaligned.h>
 #include "security.h"
 
 #include "policydb.h"
@@ -2108,7 +2109,7 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
 {
 	int i, j, rc;
 	u32 nel, len;
-	__le32 buf[3];
+	__le32 buf[4];
 	struct ocontext *l, *c;
 	u32 nodebuf[8];
 
@@ -2218,20 +2219,20 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
 				break;
 			}
 			case OCON_IBPKEY:
-				rc = next_entry(nodebuf, fp, sizeof(u32) * 4);
+				rc = next_entry(buf, fp, sizeof(u32) * 4);
 				if (rc)
 					goto out;
 
-				c->u.ibpkey.subnet_prefix = be64_to_cpu(*((__be64 *)nodebuf));
+				c->u.ibpkey.subnet_prefix = get_unaligned_be64(buf);
 
-				if (nodebuf[2] > 0xffff ||
-				    nodebuf[3] > 0xffff) {
+				if (le32_to_cpu(buf[2]) > 0xffff ||
+				    le32_to_cpu(buf[3]) > 0xffff) {
 					rc = -EINVAL;
 					goto out;
 				}
 
-				c->u.ibpkey.low_pkey = le32_to_cpu(nodebuf[2]);
-				c->u.ibpkey.high_pkey = le32_to_cpu(nodebuf[3]);
+				c->u.ibpkey.low_pkey = le32_to_cpu(buf[2]);
+				c->u.ibpkey.high_pkey = le32_to_cpu(buf[3]);
 
 				rc = context_read_and_validate(&c->context[0],
 							       p,
@@ -2249,7 +2250,8 @@ static int ocontext_read(struct policydb *p, struct policydb_compat_info *info,
 				if (rc)
 					goto out;
 
-				if (buf[1] > 0xff || buf[1] == 0) {
+				if (le32_to_cpu(buf[1]) > 0xff ||
+				    le32_to_cpu(buf[1]) == 0) {
 					rc = -EINVAL;
 					goto out;
 				}
@@ -3105,7 +3107,7 @@ static int ocontext_write(struct policydb *p, struct policydb_compat_info *info,
 {
 	unsigned int i, j, rc;
 	size_t nel, len;
-	__le32 buf[3];
+	__le32 buf[4];
 	u32 nodebuf[8];
 	struct ocontext *c;
 	for (i = 0; i < info->ocon_num; i++) {
@@ -3192,12 +3194,12 @@ static int ocontext_write(struct policydb *p, struct policydb_compat_info *info,
 					return rc;
 				break;
 			case OCON_IBPKEY:
-				*((__be64 *)nodebuf) = cpu_to_be64(c->u.ibpkey.subnet_prefix);
+				put_unaligned_be64(c->u.ibpkey.subnet_prefix, buf);
 
-				nodebuf[2] = cpu_to_le32(c->u.ibpkey.low_pkey);
-				nodebuf[3] = cpu_to_le32(c->u.ibpkey.high_pkey);
+				buf[2] = cpu_to_le32(c->u.ibpkey.low_pkey);
+				buf[3] = cpu_to_le32(c->u.ibpkey.high_pkey);
 
-				rc = put_entry(nodebuf, sizeof(u32), 4, fp);
+				rc = put_entry(buf, sizeof(u32), 4, fp);
 				if (rc)
 					return rc;
 				rc = context_write(p, &c->context[0], fp);
-- 
2.17.1