From 7623b22d1d59c78033425a2448613837bcd203a2 Mon Sep 17 00:00:00 2001 From: Lasse Collin Date: Thu, 8 Dec 2022 17:30:09 +0200 Subject: [PATCH] liblzma: Check for unexpected NULL pointers in block_header_decode(). The API docs gave an impression that such checks are done but they actually weren't done. In practice it made little difference since the calling code has a bug if these are NULL. Thanks to Jia Tan for the original patch that checked for block->filters == NULL. --- src/liblzma/common/block_header_decoder.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/src/liblzma/common/block_header_decoder.c b/src/liblzma/common/block_header_decoder.c index 2e1135dd..060479b4 100644 --- a/src/liblzma/common/block_header_decoder.c +++ b/src/liblzma/common/block_header_decoder.c @@ -39,6 +39,10 @@ lzma_block_header_decode(lzma_block *block, // are invalid or over 63 bits, or if the header is too small // to contain the claimed information. + // Catch unexpected NULL pointers. + if (block == NULL || block->filters == NULL || in == NULL) + return LZMA_PROG_ERROR; + // Initialize the filter options array. This way the caller can // safely free() the options even if an error occurs in this function. for (size_t i = 0; i <= LZMA_FILTERS_MAX; ++i) {