Check for overflow

1 files changed, 6 insertions, 0 deletions

diff --git a/tr8as.c b/tr8as.c
index 0237683..5e57b81 100644
--- a/tr8as.c
+++ b/tr8as.c
@@ -719,6 +719,9 @@ static uint8_t parse_db(As *as, char **c)
         else if (!new_ref(as, word, 0xff, as->addr))
             return 0;
 
+        if (as->addr + 1 > UINT16_MAX)
+            return error_l("Memory overflow", &as->loc, "output is more than 65535 bytes");
+
         as->out[as->addr++] = imm & 0xff;
         if (as->addr > as->size)
             as->size = as->addr;
@@ -754,6 +757,9 @@ static uint8_t parse_dw(As *as, char **c)
                 && !new_ref(as, word, 0xffff, as->addr))
             return 0;
 
+        if (as->addr + 2 > UINT16_MAX)
+            return error_l("Memory overflow", &as->loc, "output is more than 65535 bytes");
+
         as->out[as->addr++] = imm & 0xff;
         as->out[as->addr++] = imm >> 8;
         if (as->addr > as->size)