phar: cap decompression output against declared uncompressed_filesize#44
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phar: cap decompression output against declared uncompressed_filesize#44
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phar_open_entry_fp() decompressed entries by streaming compressed_filesize bytes through a filter into a tmpfile, then checked output size after the full copy. A crafted phar whose compressed data expanded beyond uncompressed_filesize could write large amounts to disk before the check ran. Replace the single php_stream_copy_to_stream_ex() call with an 8 KiB chunked loop that flushes the decompression filter and checks running output size after each chunk. Abort when output exceeds uncompressed_filesize.
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Promoted to php#21806. |
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Prevents decompression amplification in
phar_open_entry_fp().The function decompressed entries by streaming
compressed_filesizebytes through a filter into a tmpfile, then checked the output size after the full copy. A crafted phar whose compressed data expanded beyonduncompressed_filesizecould write large amounts to disk before the check ran.Replaces the single
php_stream_copy_to_stream_ex()call with an 8 KiB chunked loop that flushes the decompression filter and checks the running output size after each chunk. Aborts when output exceedsuncompressed_filesize.