From d47be9dea453b824aa16992eab34edc2e7921f51 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sat, 25 Jan 2025 11:55:20 +0100
Subject: [PATCH 1/3] fix UBSan failures for LZMA objects

---
 Modules/_lzmamodule.c | 17 +++++++++++------
 1 file changed, 11 insertions(+), 6 deletions(-)

diff --git a/Modules/_lzmamodule.c b/Modules/_lzmamodule.c
index 97f3a8f03da9a8..ece6f5fa286b0a 100644
--- a/Modules/_lzmamodule.c
+++ b/Modules/_lzmamodule.c
@@ -126,6 +126,9 @@ typedef struct {
     PyThread_type_lock lock;
 } Decompressor;
 
+#define _Compressor_CAST(op)    ((Compressor *)(op))
+#define _Decompressor_CAST(op)  ((Decompressor *)(op))
+
 /* Helper functions. */
 
 static int
@@ -857,14 +860,15 @@ Compressor_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 }
 
 static void
-Compressor_dealloc(Compressor *self)
+Compressor_dealloc(PyObject *op)
 {
+    Compressor *self = _Compressor_CAST(op);
     lzma_end(&self->lzs);
     if (self->lock != NULL) {
         PyThread_free_lock(self->lock);
     }
     PyTypeObject *tp = Py_TYPE(self);
-    tp->tp_free((PyObject *)self);
+    tp->tp_free(self);
     Py_DECREF(tp);
 }
 
@@ -875,7 +879,7 @@ static PyMethodDef Compressor_methods[] = {
 };
 
 static int
-Compressor_traverse(Compressor *self, visitproc visit, void *arg)
+Compressor_traverse(PyObject *self, visitproc visit, void *arg)
 {
     Py_VISIT(Py_TYPE(self));
     return 0;
@@ -1304,8 +1308,9 @@ _lzma_LZMADecompressor_impl(PyTypeObject *type, int format,
 }
 
 static void
-Decompressor_dealloc(Decompressor *self)
+Decompressor_dealloc(PyObject *op)
 {
+    Decompressor *self = _Decompressor_CAST(op);
     if(self->input_buffer != NULL)
         PyMem_Free(self->input_buffer);
 
@@ -1315,12 +1320,12 @@ Decompressor_dealloc(Decompressor *self)
         PyThread_free_lock(self->lock);
     }
     PyTypeObject *tp = Py_TYPE(self);
-    tp->tp_free((PyObject *)self);
+    tp->tp_free(self);
     Py_DECREF(tp);
 }
 
 static int
-Decompressor_traverse(Decompressor *self, visitproc visit, void *arg)
+Decompressor_traverse(PyObject *self, visitproc visit, void *arg)
 {
     Py_VISIT(Py_TYPE(self));
     return 0;

From f9fc53d67870dbb0369be8b913dfe0c5aa26d7a7 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sat, 25 Jan 2025 11:55:41 +0100
Subject: [PATCH 2/3] suppress unused return values

---
 Modules/_lzmamodule.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Modules/_lzmamodule.c b/Modules/_lzmamodule.c
index ece6f5fa286b0a..4a595bb1cbacaa 100644
--- a/Modules/_lzmamodule.c
+++ b/Modules/_lzmamodule.c
@@ -1638,7 +1638,7 @@ lzma_clear(PyObject *module)
 static void
 lzma_free(void *module)
 {
-    lzma_clear((PyObject *)module);
+    (void)lzma_clear((PyObject *)module);
 }
 
 static PyModuleDef _lzmamodule = {

From 9a206254a76bb0ba336cc25c86d45cb16626642e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?B=C3=A9n=C3=A9dikt=20Tran?=
 <10796600+picnixz@users.noreply.github.com>
Date: Sat, 8 Feb 2025 10:11:40 +0100
Subject: [PATCH 3/3] Do not use `_` + capital letter in new code as it is also
 UB.

---
 Modules/_lzmamodule.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/Modules/_lzmamodule.c b/Modules/_lzmamodule.c
index 4a595bb1cbacaa..0058e2eec2ef16 100644
--- a/Modules/_lzmamodule.c
+++ b/Modules/_lzmamodule.c
@@ -126,8 +126,8 @@ typedef struct {
     PyThread_type_lock lock;
 } Decompressor;
 
-#define _Compressor_CAST(op)    ((Compressor *)(op))
-#define _Decompressor_CAST(op)  ((Decompressor *)(op))
+#define Compressor_CAST(op)     ((Compressor *)(op))
+#define Decompressor_CAST(op)   ((Decompressor *)(op))
 
 /* Helper functions. */
 
@@ -862,7 +862,7 @@ Compressor_new(PyTypeObject *type, PyObject *args, PyObject *kwargs)
 static void
 Compressor_dealloc(PyObject *op)
 {
-    Compressor *self = _Compressor_CAST(op);
+    Compressor *self = Compressor_CAST(op);
     lzma_end(&self->lzs);
     if (self->lock != NULL) {
         PyThread_free_lock(self->lock);
@@ -1310,7 +1310,7 @@ _lzma_LZMADecompressor_impl(PyTypeObject *type, int format,
 static void
 Decompressor_dealloc(PyObject *op)
 {
-    Decompressor *self = _Decompressor_CAST(op);
+    Decompressor *self = Decompressor_CAST(op);
     if(self->input_buffer != NULL)
         PyMem_Free(self->input_buffer);