Fix an out-of-bounds access

Issue seen on CheriBSD running on a Morello board (core dump when running the test suite).
InterNetNews · Nov 2, 2023 · 080646a · 080646a
1 parent 88d493e
commit 080646a
Showing 1 changed file with 2 additions and 1 deletion.
diff --git a/lib/headers.c b/lib/headers.c
@@ -47,6 +47,7 @@ bool
 IsValidHeaderBody(const char *p)
 {
     bool emptycontentline = true;
+    const char *start = p;
 
     /* Not NULL and not empty. */
     if (p == NULL || *p == '\0')
@@ -73,7 +74,7 @@ IsValidHeaderBody(const char *p)
              * re-initialize emptycontentline to true. */
             emptycontentline = true;
             continue;
-        } else if (p[-1] == '\r') {
+        } else if (p > start && p[-1] == '\r') {
             /* Case of CR not followed by LF (handled at the previous
              * if statement). */
             return false;