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qapi: Do not cast function pointers

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Using -fsanitize=undefined with Clang v18 causes an error if function
pointers are casted:

 qapi/qapi-clone-visitor.c:188:5: runtime error: call to function visit_type_SocketAddress through pointer to incorrect function type 'bool (*)(struct Visitor *, const char *, void **, struct Error **)'
 /tmp/qemu-ubsan/qapi/qapi-visit-sockets.c:487: note: visit_type_SocketAddress defined here
     #0 0x5642aa2f7f3b in qapi_clone qapi/qapi-clone-visitor.c:188:5
     #1 0x5642aa2c8ce5 in qio_channel_socket_listen_async io/channel-socket.c:285:18
     #2 0x5642aa2b8903 in test_io_channel_setup_async tests/unit/test-io-channel-socket.c:116:5
     #3 0x5642aa2b8204 in test_io_channel tests/unit/test-io-channel-socket.c:179:9
     #4 0x5642aa2b8129 in test_io_channel_ipv4 tests/unit/test-io-channel-socket.c:323:5
     ...

It also prevents enabling the strict mode of CFI which is currently
disabled with -fsanitize-cfi-icall-generalize-pointers.

The problematic casts are necessary to pass visit_type_T() and
visit_type_T_members() as callbacks to qapi_clone() and qapi_clone_members(),
respectively. Open-code these two functions to avoid the callbacks, and
thus the type casts.

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2346
Signed-off-by: Akihiko Odaki <akihiko.odaki@daynix.com>
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Message-ID: <20240524-xkb-v4-3-2de564e5c859@daynix.com>
[thuth: Improve commit message according to Markus' suggestions]
Signed-off-by: Thomas Huth <thuth@redhat.com>
This commit is contained in:
Akihiko Odaki 2024-05-24 14:35:49 +09:00 committed by Thomas Huth
parent a3b3ad72e8
commit b04091393e
2 changed files with 28 additions and 39 deletions
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37
include/qapi/clone-visitor.h
View File

@ -11,6 +11,7 @@
#ifndef QAPI_CLONE_VISITOR_H
#define QAPI_CLONE_VISITOR_H
#include "qapi/error.h"
#include "qapi/visitor.h"
/*
@ -20,11 +21,8 @@
*/
typedef struct QapiCloneVisitor QapiCloneVisitor;
void *qapi_clone(const void *src, bool (*visit_type)(Visitor *, const char *,
void **, Error **));
void qapi_clone_members(void *dst, const void *src, size_t sz,
bool (*visit_type_members)(Visitor *, void *,
Error **));
Visitor *qapi_clone_visitor_new(void);
Visitor *qapi_clone_members_visitor_new(void);
/*
* Deep-clone QAPI object @src of the given @type, and return the result.
@ -32,10 +30,18 @@ void qapi_clone_members(void *dst, const void *src, size_t sz,
* Not usable on QAPI scalars (integers, strings, enums), nor on a
* QAPI object that references the 'any' type. Safe when @src is NULL.
*/
#define QAPI_CLONE(type, src) \
((type *)qapi_clone(src, \
(bool (*)(Visitor *, const char *, void **, \
Error **))visit_type_ ## type))
#define QAPI_CLONE(type, src) \
({ \
Visitor *v_; \
type *dst_ = (type *) (src); /* Cast away const */ \
\
if (dst_) { \
v_ = qapi_clone_visitor_new(); \
visit_type_ ## type(v_, NULL, &dst_, &error_abort); \
visit_free(v_); \
} \
dst_; \
})
/*
* Copy deep clones of @type members from @src to @dst.
@ -43,9 +49,14 @@ void qapi_clone_members(void *dst, const void *src, size_t sz,
* Not usable on QAPI scalars (integers, strings, enums), nor on a
* QAPI object that references the 'any' type.
*/
#define QAPI_CLONE_MEMBERS(type, dst, src) \
qapi_clone_members(dst, src, sizeof(type), \
(bool (*)(Visitor *, void *, \
Error **))visit_type_ ## type ## _members)
#define QAPI_CLONE_MEMBERS(type, dst, src) \
({ \
Visitor *v_; \
\
v_ = qapi_clone_members_visitor_new(); \
*(type *)(dst) = *(src); \
visit_type_ ## type ## _members(v_, (type *)(dst), &error_abort); \
visit_free(v_); \
})
#endif

30
qapi/qapi-clone-visitor.c
View File

@ -149,7 +149,7 @@ static void qapi_clone_free(Visitor *v)
g_free(v);
}
static Visitor *qapi_clone_visitor_new(void)
Visitor *qapi_clone_visitor_new(void)
{
QapiCloneVisitor *v;
@ -174,31 +174,9 @@ static Visitor *qapi_clone_visitor_new(void)
return &v->visitor;
}
void *qapi_clone(const void *src, bool (*visit_type)(Visitor *, const char *,
void **, Error **))
Visitor *qapi_clone_members_visitor_new(void)
{
Visitor *v;
void *dst = (void *) src; /* Cast away const */
if (!src) {
return NULL;
}
v = qapi_clone_visitor_new();
visit_type(v, NULL, &dst, &error_abort);
visit_free(v);
return dst;
}
void qapi_clone_members(void *dst, const void *src, size_t sz,
bool (*visit_type_members)(Visitor *, void *,
Error **))
{
Visitor *v;
v = qapi_clone_visitor_new();
memcpy(dst, src, sz);
Visitor *v = qapi_clone_visitor_new();
to_qcv(v)->depth++;
visit_type_members(v, dst, &error_abort);
visit_free(v);
return v;
}