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authorDenys Vlasenko2021-06-15 15:07:57 +0200
committerDenys Vlasenko2021-11-23 05:31:30 +0100
commitd326be2850ea2bd78fe2c22d6c45c3b861d82937 (patch)
treedc1393b34692db7081d266e70b2fb03a32ac66e8
parentbcc5b0e6caca6c7602a6a41faa5f980292e0fbc5 (diff)
downloadbusybox-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.c5
-rwxr-xr-xtestsuite/unlzma.tests17
-rw-r--r--testsuite/unlzma_issue_3.lzmabin0 -> 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
new file mode 100644
index 0000000..cc60f29
--- /dev/null
+++ b/testsuite/unlzma_issue_3.lzma
Binary files differ