https://github.com/python/cpython/commit/0154405350c272833bd51f68138223655e142a37
commit: 0154405350c272833bd51f68138223655e142a37
branch: main
author: Radislav Chugunov <[email protected]>
committer: serhiy-storchaka <[email protected]>
date: 2024-01-17T13:15:44Z
summary:
gh-104282: Fix null pointer dereference in `lzma._decode_filter_properties`
(GH-104283)
files:
A Misc/NEWS.d/next/Library/2023-05-08-09-30-00.gh-issue-104282.h4c6Eb.rst
M Lib/test/test_lzma.py
M Modules/_lzmamodule.c
diff --git a/Lib/test/test_lzma.py b/Lib/test/test_lzma.py
index 13b200912f6abd..65e6488c5d7b10 100644
--- a/Lib/test/test_lzma.py
+++ b/Lib/test/test_lzma.py
@@ -1401,6 +1401,14 @@ def test__decode_filter_properties(self):
self.assertEqual(filterspec["lc"], 3)
self.assertEqual(filterspec["dict_size"], 8 << 20)
+ # see gh-104282
+ filters = [lzma.FILTER_X86, lzma.FILTER_POWERPC,
+ lzma.FILTER_IA64, lzma.FILTER_ARM,
+ lzma.FILTER_ARMTHUMB, lzma.FILTER_SPARC]
+ for f in filters:
+ filterspec = lzma._decode_filter_properties(f, b"")
+ self.assertEqual(filterspec, {"id": f})
+
def test_filter_properties_roundtrip(self):
spec1 = lzma._decode_filter_properties(
lzma.FILTER_LZMA1, b"]\x00\x00\x80\x00")
diff --git
a/Misc/NEWS.d/next/Library/2023-05-08-09-30-00.gh-issue-104282.h4c6Eb.rst
b/Misc/NEWS.d/next/Library/2023-05-08-09-30-00.gh-issue-104282.h4c6Eb.rst
new file mode 100644
index 00000000000000..569ce66a5b9d5f
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2023-05-08-09-30-00.gh-issue-104282.h4c6Eb.rst
@@ -0,0 +1,3 @@
+Fix null pointer dereference in :func:`lzma._decode_filter_properties`
+due to improper handling of BCJ filters with properties of zero length.
+Patch by Radislav Chugunov.
diff --git a/Modules/_lzmamodule.c b/Modules/_lzmamodule.c
index eb90c308d16d19..f6bfbfa62687b8 100644
--- a/Modules/_lzmamodule.c
+++ b/Modules/_lzmamodule.c
@@ -492,7 +492,9 @@ build_filter_spec(const lzma_filter *f)
case LZMA_FILTER_ARMTHUMB:
case LZMA_FILTER_SPARC: {
lzma_options_bcj *options = f->options;
- ADD_FIELD(options, start_offset);
+ if (options) {
+ ADD_FIELD(options, start_offset);
+ }
break;
}
default:
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