diff --git a/proj/intercept/src/intercept.c b/proj/intercept/src/intercept.c
index 542e304..7a95e40 100644
--- a/proj/intercept/src/intercept.c
+++ b/proj/intercept/src/intercept.c
@@ -1419,7 +1419,7 @@ int sym(sigaction)(int sig, const struct sigaction *restrict act, struct sigacti
             if (sigismember(&act->sa_mask, i) != 1)
                 continue;
             if (maskstr[0] != 0) strcat(maskstr, ",");
-            strcat(maskstr, getsigstr(i));
+            sprintf(maskstr + strlen(maskstr), "%i:%s", i, getsigstr(i));
         }
         if (!verbosity) {
             msg("sigaction(%i:%s, %p:{}, %p)" ret_str, sig, sigstr, act, oact, ret_data);
@@ -1462,7 +1462,7 @@ int sym(sigaction)(int sig, const struct sigaction *restrict act, struct sigacti
             if (sigismember(&oact->sa_mask, i) != 1)
                 continue;
             if (maskstr[0] != 0) strcat(maskstr, ",");
-            strcat(maskstr, getsigstr(i));
+            sprintf(maskstr + strlen(maskstr), "%i:%s", i, getsigstr(i));
         }
         msg("return %i; errno %s; oact={sa_flags: 0x%x:%s, %s: %p, sa_mask: [%s]}", ret, strerrorname_np(errno), oact->sa_flags, flgstr, name, ptr, maskstr);
     } else {
diff --git a/proj/server/src/intercept/__init__.py b/proj/server/src/intercept/__init__.py
index a97ea2d..8664ca5 100644
--- a/proj/server/src/intercept/__init__.py
+++ b/proj/server/src/intercept/__init__.py
@@ -23,7 +23,7 @@ class Flags(NamedTuple):
     flags: list[str]
 
 StructTimeSpec = TypedDict('StructTimeSpec', {'tv_sec': int, 'tv_nsec': int})
-StructSigAction = TypedDict('StructSigAction', {'sa_flags': Flags, 'sa_handler': NotRequired[Pointer], 'sa_sigaction': NotRequired[Pointer], 'sa_mask': list[str]})
+StructSigAction = TypedDict('StructSigAction', {'sa_flags': Flags, 'sa_handler': NotRequired[Pointer], 'sa_sigaction': NotRequired[Pointer], 'sa_mask': list[Constant]})
 StructSockAddr = TypedDict('StructSockAddr', {'sa_family': Constant, 'sa_data': NotRequired[bytes],
                                               'sun_path': NotRequired[bytes],
                                               'sin_addr': NotRequired[bytes], 'sin_port': NotRequired[int],