[PATCH v2] libsepol: add missing ibendport port validity check

[Ondrej Mosnacek <omosnace@redhat.com>]

The kernel checks if the port is in the range 1-255 when loading an
ibenportcon rule. Add the same check to libsepol.

Fixes: 118c0cd1038e ("libsepol: Add ibendport ocontext handling")
Signed-off-by: Ondrej Mosnacek <omosnace@redhat.com>
---
 libsepol/src/policydb.c | 11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)

Changes in v2:
 - use UINT8_MAX as the limit for ibendport.port value to emphasize that
   it is an 8-bit value

diff --git a/libsepol/src/policydb.c b/libsepol/src/policydb.c
index db6765ba..96176d80 100644
--- a/libsepol/src/policydb.c
+++ b/libsepol/src/policydb.c
@@ -2854,7 +2854,9 @@ static int ocontext_read_selinux(struct policydb_compat_info *info,
 					return -1;
 				break;
 			}
-			case OCON_IBENDPORT:
+			case OCON_IBENDPORT: {
+				uint32_t port;
+
 				rc = next_entry(buf, fp, sizeof(uint32_t) * 2);
 				if (rc < 0)
 					return -1;
@@ -2862,6 +2864,10 @@ static int ocontext_read_selinux(struct policydb_compat_info *info,
 				if (len == 0 || len > IB_DEVICE_NAME_MAX - 1)
 					return -1;
 
+				port = le32_to_cpu(buf[1]);
+				if (port > UINT8_MAX || port == 0)
+					return -1;
+
 				c->u.ibendport.dev_name = malloc(len + 1);
 				if (!c->u.ibendport.dev_name)
 					return -1;
@@ -2869,11 +2875,12 @@ static int ocontext_read_selinux(struct policydb_compat_info *info,
 				if (rc < 0)
 					return -1;
 				c->u.ibendport.dev_name[len] = 0;
-				c->u.ibendport.port = le32_to_cpu(buf[1]);
+				c->u.ibendport.port = port;
 				if (context_read_and_validate
 				    (&c->context[0], p, fp))
 					return -1;
 				break;
+			}
 			case OCON_PORT:
 				rc = next_entry(buf, fp, sizeof(uint32_t) * 3);
 				if (rc < 0)
-- 
2.17.2