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| author | Denys Vlasenko | 2021-06-15 15:07:57 +0200 |
|---|---|---|
| committer | Denys Vlasenko | 2021-11-23 05:31:30 +0100 |
| commit | d326be2850ea2bd78fe2c22d6c45c3b861d82937 (patch) | |
| tree | dc1393b34692db7081d266e70b2fb03a32ac66e8 | |
| parent | bcc5b0e6caca6c7602a6a41faa5f980292e0fbc5 (diff) | |
| download | busybox-d326be2850ea2bd78fe2c22d6c45c3b861d82937.zip busybox-d326be2850ea2bd78fe2c22d6c45c3b861d82937.tar.gz | |
unlzma: fix a case where we could read before beginning of buffer
Testcase:
21 01 01 00 00 00 00 00 e7 01 01 01 ef 00 df b6
00 17 02 10 11 0f ff 00 16 00 00
Unfortunately, the bug is not reliably causing a segfault,
the behavior depends on what's in memory before the buffer.
function old new delta
unpack_lzma_stream 2762 2768 +6
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>
(cherry picked from commit 04f052c56ded5ab6a904e3a264a73dc0412b2e78)
| -rw-r--r-- | archival/libarchive/decompress_unlzma.c | 5 | ||||
| -rwxr-xr-x | testsuite/unlzma.tests | 17 | ||||
| -rw-r--r-- | testsuite/unlzma_issue_3.lzma | bin | 0 -> 27 bytes |
3 files changed, 17 insertions, 5 deletions
diff --git a/archival/libarchive/decompress_unlzma.c b/archival/libarchive/decompress_unlzma.c index 0744f23..fb5aac8 100644 --- a/archival/libarchive/decompress_unlzma.c +++ b/archival/libarchive/decompress_unlzma.c @@ -290,8 +290,11 @@ unpack_lzma_stream(transformer_state_t *xstate) uint32_t pos; pos = buffer_pos - rep0; - if ((int32_t)pos < 0) + if ((int32_t)pos < 0) { pos += header.dict_size; + if ((int32_t)pos < 0) + goto bad; + } match_byte = buffer[pos]; do { int bit; diff --git a/testsuite/unlzma.tests b/testsuite/unlzma.tests index 0e98afe..fcc6e94 100755 --- a/testsuite/unlzma.tests +++ b/testsuite/unlzma.tests @@ -8,14 +8,23 @@ # Damaged encrypted streams testing "unlzma (bad archive 1)" \ - "unlzma <unlzma_issue_1.lzma >/dev/null; echo \$?" \ -"1 + "unlzma <unlzma_issue_1.lzma 2>&1 >/dev/null; echo \$?" \ +"unlzma: corrupted data +1 " "" "" # Damaged encrypted streams testing "unlzma (bad archive 2)" \ - "unlzma <unlzma_issue_2.lzma >/dev/null; echo \$?" \ -"1 + "unlzma <unlzma_issue_2.lzma 2>&1 >/dev/null; echo \$?" \ +"unlzma: corrupted data +1 +" "" "" + +# Damaged encrypted streams +testing "unlzma (bad archive 3)" \ + "unlzma <unlzma_issue_3.lzma 2>&1 >/dev/null; echo \$?" \ +"unlzma: corrupted data +1 " "" "" exit $FAILCOUNT diff --git a/testsuite/unlzma_issue_3.lzma b/testsuite/unlzma_issue_3.lzma Binary files differnew file mode 100644 index 0000000..cc60f29 --- /dev/null +++ b/testsuite/unlzma_issue_3.lzma |