utils: fix bad handling of utf-8 parsing (oss-fuzz 26304)

Signed-off-by: davkor <david@adalogics.com>
fluent · Nov 6, 2020 · 73410b3 · 73410b3
1 parent 3a84a8a
commit 73410b3
Showing 1 changed file with 9 additions and 0 deletions.
diff --git a/src/flb_utils.c b/src/flb_utils.c
@@ -647,6 +647,9 @@ int flb_utils_write_str(char *buf, int *off, size_t size,
                 return FLB_FALSE;
             }
             len = snprintf(tmp, sizeof(tmp) - 1, "\\u%.4hhx", (unsigned char) c);
+            if ((available - written) < len) {
+                return FLB_FALSE;
+            }
             encoded_to_buf(p, tmp, len);
             p += len;
         }
@@ -677,6 +680,9 @@ int flb_utils_write_str(char *buf, int *off, size_t size,
             }
             else {
                 len = snprintf(tmp, sizeof(tmp) - 1, "\\u%.4x", codepoint);
+                if ((available - written) < len) {
+                    return FLB_FALSE;
+                }
                 encoded_to_buf(p, tmp, len);
                 p += len;
             }
@@ -708,6 +714,9 @@ int flb_utils_write_str(char *buf, int *off, size_t size,
             }
             else {
                 len = snprintf(tmp, sizeof(tmp) - 1, "\\u%04x", codepoint);
+                if ((available - written) < len) {
+                    return FLB_FALSE;
+                }
                 encoded_to_buf(p, tmp, len);
                 p += len;
             }