issue: 4583806 Coverity var_deref_op and var_deref_model fixes

Fix Coverity-reported null pointer dereference warnings by adding
explicit null checks and Coverity suppression comments to document
intentional pointer dereferencing after validation, eliminating false
positives.

Changes:
- Refactored SYSCALL macro to use statement expression with explicit
  if/else for clearer control flow to Coverity static analyzer
- Added suppression comment for dbrec pointer which is guaranteed valid
  after successful xlio_ib_mlx5dv_init_obj() call
- Added suppression comment for p_iov pointer which is validated before
  reaching OS transmit fallback path

Updated files:
- src/core/sock/sock-redirect.h
- src/core/ib/mlx5/ib_mlx5.cpp
- libxlio/src/core/ib/mlx5/ib_mlx5.cpp
- src/core/sock/sockinfo_udp.cpp
- libxlio/src/core/sock/sockinfo_udp.cpp

Signed-off-by: Omri Ritblat <[email protected]>

Author: OmriRitblat

src/core/config/descriptor_providers/schema_analyzer.cpp

@@ -218,10 +218,13 @@ constraint_config schema_analyzer::analyze_constraint_config()
         for_each_oneof_option(one_of_field, [&](json_object *option) {
             json_object *type_field =
                 json_utils::get_field(option, config_strings::schema::JSON_TYPE);
-            std::string type_str = json_object_get_string(type_field);
-            if (type_str == config_strings::schema_types::JSON_TYPE_INTEGER) {
-                extract_constraints_from_json(option, config);
-            }
+                const char *type_cstr = json_object_get_string(type_field);
+                if (type_cstr) {
+                    std::string type_str = type_cstr;
+                    if (type_str == config_strings::schema_types::JSON_TYPE_INTEGER) {
+                        extract_constraints_from_json(option, config);
+                    }
+                }
         });
     }
 

src/core/ib/mlx5/ib_mlx5.cpp

@@ -38,6 +38,7 @@ int xlio_ib_mlx5_get_qp_tx(xlio_ib_mlx5_qp_t *mlx5_qp)
 
     VALGRIND_MAKE_MEM_DEFINED(&dqp, sizeof(dqp));
     mlx5_qp->qpn = mlx5_qp->qp->qp_num;
+    /* coverity[var_deref_op] dbrec is guaranteed to be valid after successful xlio_ib_mlx5dv_init_obj */
     mlx5_qp->sq.dbrec = &dqp.dbrec[MLX5_SND_DBR];
     mlx5_qp->sq.buf = dqp.sq.buf;
     mlx5_qp->sq.wqe_cnt = dqp.sq.wqe_cnt;

src/core/sock/sockinfo_udp.cpp

@@ -2187,7 +2187,12 @@ ssize_t sockinfo_udp::tx(xlio_tx_call_attr_t &tx_arg)
 
 tx_packet_to_os:
     // Calling OS transmit
-    ret = tx_os(tx_arg.opcode, p_iov, sz_iov, __flags, __dst, __dstlen);
+    if (unlikely(!p_iov)) {
+        errno = EINVAL;
+        ret = -1;
+    } else {
+        ret = tx_os(tx_arg.opcode, p_iov, sz_iov, __flags, __dst, __dstlen);
+    }
 
 tx_packet_to_os_stats:
     save_stats_tx_os(ret);