From 88311f46cdfc719d26bb99d3b47944eb92ceae02 Mon Sep 17 00:00:00 2001 From: Ondrej Dubaj Date: Tue, 30 Apr 2019 11:50:33 +0200 Subject: [PATCH] Avoid a double-free when a window size of 0 is specified new_size can be 0 with a malicious or corrupted RAR archive. realloc(area, 0) is equivalent to free(area), so the region would be free()d here and the free()d again in the cleanup function. Found with a setup running AFL, afl-rb, and qsym. --- libarchive/archive_read_support_format_rar.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/libarchive/archive_read_support_format_rar.c b/libarchive/archive_read_support_format_rar.c index c4a8278..3f88eef 100644 --- a/libarchive/archive_read_support_format_rar.c +++ b/libarchive/archive_read_support_format_rar.c @@ -2317,6 +2317,11 @@ parse_codes(struct archive_read *a) new_size = DICTIONARY_MAX_SIZE; else new_size = rar_fls((unsigned int)rar->unp_size) << 1; + if (new_size == 0) { + archive_set_error(&a->archive, ARCHIVE_ERRNO_FILE_FORMAT, + "Zero window size is invalid."); + return (ARCHIVE_FATAL); + } new_window = realloc(rar->lzss.window, new_size); if (new_window == NULL) { archive_set_error(&a->archive, ENOMEM, -- 2.17.1