| From fe791386ebc270219ca00406c9fdadc5130b64ee Mon Sep 17 00:00:00 2001 |
| From: Samuel Sapalski <samuel.sapalski@nokia.com> |
| Date: Wed, 3 Mar 2021 16:31:22 +0100 |
| Subject: [PATCH] decompress_gunzip: Fix DoS if gzip is corrupt |
| |
| On certain corrupt gzip files, huft_build will set the error bit on |
| the result pointer. If afterwards abort_unzip is called huft_free |
| might run into a segmentation fault or an invalid pointer to |
| free(p). |
| |
| In order to mitigate this, we check in huft_free if the error bit |
| is set and clear it before the linked list is freed. |
| |
| Signed-off-by: Samuel Sapalski <samuel.sapalski@nokia.com> |
| Signed-off-by: Peter Kaestle <peter.kaestle@nokia.com> |
| Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com> |
| |
| Upstream-Status: Backport |
| CVE: CVE-2021-28831 |
| Signed-off-by: Chen Qi <Qi.Chen@windriver.com> |
| --- |
| archival/libarchive/decompress_gunzip.c | 12 ++++++++++-- |
| 1 file changed, 10 insertions(+), 2 deletions(-) |
| |
| diff --git a/archival/libarchive/decompress_gunzip.c b/archival/libarchive/decompress_gunzip.c |
| index eb3b64930..e93cd5005 100644 |
| --- a/archival/libarchive/decompress_gunzip.c |
| +++ b/archival/libarchive/decompress_gunzip.c |
| @@ -220,10 +220,20 @@ static const uint8_t border[] ALIGN1 = { |
| * each table. |
| * t: table to free |
| */ |
| +#define BAD_HUFT(p) ((uintptr_t)(p) & 1) |
| +#define ERR_RET ((huft_t*)(uintptr_t)1) |
| static void huft_free(huft_t *p) |
| { |
| huft_t *q; |
| |
| + /* |
| + * If 'p' has the error bit set we have to clear it, otherwise we might run |
| + * into a segmentation fault or an invalid pointer to free(p) |
| + */ |
| + if (BAD_HUFT(p)) { |
| + p = (huft_t*)((uintptr_t)(p) ^ (uintptr_t)(ERR_RET)); |
| + } |
| + |
| /* Go through linked list, freeing from the malloced (t[-1]) address. */ |
| while (p) { |
| q = (--p)->v.t; |
| @@ -289,8 +299,6 @@ static unsigned fill_bitbuffer(STATE_PARAM unsigned bitbuffer, unsigned *current |
| * or a valid pointer to a Huffman table, ORed with 0x1 if incompete table |
| * is given: "fixed inflate" decoder feeds us such data. |
| */ |
| -#define BAD_HUFT(p) ((uintptr_t)(p) & 1) |
| -#define ERR_RET ((huft_t*)(uintptr_t)1) |
| static huft_t* huft_build(const unsigned *b, const unsigned n, |
| const unsigned s, const struct cp_ext *cp_ext, |
| unsigned *m) |