CVE: CVE-2018-1000877 Upstream-Status: Backport Signed-off-by: Ross Burton From 021efa522ad729ff0f5806c4ce53e4a6cc1daa31 Mon Sep 17 00:00:00 2001 From: Daniel Axtens Date: Tue, 20 Nov 2018 17:56:29 +1100 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 23452222..6f419c27 100644 --- a/libarchive/archive_read_support_format_rar.c +++ b/libarchive/archive_read_support_format_rar.c @@ -2300,6 +2300,11 @@ 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, -- 2.20.0