1 From f25d254dfd4243698c31a4f3153d4ac72aa9e9bd Mon Sep 17 00:00:00 2001
2 From: Samuel Sapalski <samuel.sapalski@nokia.com>
3 Date: Wed, 3 Mar 2021 16:31:22 +0100
4 Subject: decompress_gunzip: Fix DoS if gzip is corrupt
6 On certain corrupt gzip files, huft_build will set the error bit on
7 the result pointer. If afterwards abort_unzip is called huft_free
8 might run into a segmentation fault or an invalid pointer to
11 In order to mitigate this, we check in huft_free if the error bit
12 is set and clear it before the linked list is freed.
14 Signed-off-by: Samuel Sapalski <samuel.sapalski@nokia.com>
15 Signed-off-by: Peter Kaestle <peter.kaestle@nokia.com>
16 Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
18 archival/libarchive/decompress_gunzip.c | 12 ++++++++++--
19 1 file changed, 10 insertions(+), 2 deletions(-)
21 --- a/archival/libarchive/decompress_gunzip.c
22 +++ b/archival/libarchive/decompress_gunzip.c
23 @@ -220,10 +220,20 @@ static const uint8_t border[] ALIGN1 = {
27 +#define BAD_HUFT(p) ((uintptr_t)(p) & 1)
28 +#define ERR_RET ((huft_t*)(uintptr_t)1)
29 static void huft_free(huft_t *p)
34 + * If 'p' has the error bit set we have to clear it, otherwise we might run
35 + * into a segmentation fault or an invalid pointer to free(p)
38 + p = (huft_t*)((uintptr_t)(p) ^ (uintptr_t)(ERR_RET));
41 /* Go through linked list, freeing from the malloced (t[-1]) address. */
44 @@ -289,8 +299,6 @@ static unsigned fill_bitbuffer(STATE_PAR
45 * or a valid pointer to a Huffman table, ORed with 0x1 if incompete table
46 * is given: "fixed inflate" decoder feeds us such data.
48 -#define BAD_HUFT(p) ((uintptr_t)(p) & 1)
49 -#define ERR_RET ((huft_t*)(uintptr_t)1)
50 static huft_t* huft_build(const unsigned *b, const unsigned n,
51 const unsigned s, const struct cp_ext *cp_ext,