xzlib: Fix harmless unsigned integer overflow

2025-10-24 13:33:01 +03:00 · 2023-12-19 19:47:07 +01:00
parent 1ef3566362
commit e62b0dbde5
1 changed files with 5 additions and 1 deletions
--- a/xzlib.c
+++ b/xzlib.c
@@ -321,8 +321,12 @@ is_format_lzma(xz_statep state)
     * If someone complains, this will be reconsidered.
     */
    if (dict_size != UINT32_MAX) {
-        uint32_t d = dict_size - 1;
+        uint32_t d;

+        if (dict_size == 0)
+            return 0;
+
+        d = dict_size - 1;
        d |= d >> 2;
        d |= d >> 3;
        d |= d >> 4;