BR 3392576: don't segfault on a bad %pragma limit

Don't segfault on a bad %pragma limit. Instead treat a NULL pointer as
an empty string.

Reported-by: Ren Kimura <rkx1209dev@gmail.com>
Signed-off-by: H. Peter Anvin (Intel) <hpa@zytor.com>

1 files changed, 6 insertions, 1 deletions

diff --git a/asm/nasm.c b/asm/nasm.c
index c84d6750..65116ab3 100644
--- a/asm/nasm.c
+++ b/asm/nasm.c
@@ -212,6 +212,11 @@ nasm_set_limit(const char *limit, const char *valstr)
     bool rn_error;
     int errlevel;
 
+    if (!limit)
+        limit = "";
+    if (!valstr)
+        valstr = "";
+
     for (i = 0; i <= LIMIT_MAX; i++) {
         if (!nasm_stricmp(limit, limit_info[i].name))
             break;
@@ -234,7 +239,7 @@ nasm_set_limit(const char *limit, const char *valstr)
                 errlevel = ERR_WARNING|WARN_OTHER|ERR_USAGE;
             else
                 errlevel = ERR_WARNING|WARN_PRAGMA_BAD;
-            nasm_error(errlevel, "invalid limit value: `%s'", limit);
+            nasm_error(errlevel, "invalid limit value: `%s'", valstr);
             return DIRR_ERROR;
         }
         if (val > LIMIT_MAX_VAL)