From: Robert Rose <robert.rose@mailbox.org>
Date: Sun, 24 Nov 2024 22:36:53 +0000 (+0100)
Subject: prevent possible segfault when creating seek table
X-Git-Tag: v1.5.7^2~59^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=b683c0dbe278f71e371376847deebd44fdcf392f;p=thirdparty%2Fzstd.git

prevent possible segfault when creating seek table

Add a check whether the seek table of a `ZSTD_seekable` is initialized
before creating a new seek table from it. Return `NULL`, if the check
fails.
---

diff --git a/contrib/seekable_format/zstdseek_decompress.c b/contrib/seekable_format/zstdseek_decompress.c
index 4fefc5f2e..5ee6e0541 100644
--- a/contrib/seekable_format/zstdseek_decompress.c
+++ b/contrib/seekable_format/zstdseek_decompress.c
@@ -252,6 +252,8 @@ size_t ZSTD_seekable_free(ZSTD_seekable* zs)
 
 ZSTD_seekTable* ZSTD_seekTable_create_fromSeekable(const ZSTD_seekable* zs)
 {
+    assert(zs != NULL);
+    if (zs->seekTable.entries == NULL) return NULL;
     ZSTD_seekTable* const st = (ZSTD_seekTable*)malloc(sizeof(ZSTD_seekTable));
     if (st==NULL) return NULL;