From 265deeab8913599823b475cabab10b9261e384f9 Mon Sep 17 00:00:00 2001 From: Akihiko Odaki Date: Wed, 29 May 2024 12:54:54 +0200 Subject: [PATCH] qapi: Do not cast function pointers 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 Reviewed-by: Markus Armbruster Message-ID: <20240524-xkb-v4-3-2de564e5c859@daynix.com> [thuth: Improve commit message according to Markus' suggestions] Signed-off-by: Thomas Huth Message-Id: <20240529105454.1149225-23-thuth@redhat.com> --- include/qapi/clone-visitor.h | 37 +++++++++++++++++++++++------------- qapi/qapi-clone-visitor.c | 30 ++++------------------------- 2 files changed, 28 insertions(+), 39 deletions(-) diff --git a/include/qapi/clone-visitor.h b/include/qapi/clone-visitor.h index adf9a788e232..ebc182b034d7 100644 --- a/include/qapi/clone-visitor.h +++ b/include/qapi/clone-visitor.h @@ -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 diff --git a/qapi/qapi-clone-visitor.c b/qapi/qapi-clone-visitor.c index c45c5caa3b89..bbf953698f38 100644 --- a/qapi/qapi-clone-visitor.c +++ b/qapi/qapi-clone-visitor.c @@ -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; }