Per https://discourse.gnome.org/t/port-your-module-from-g-memdup-to-g-memdup2-now/5538
The old API took the size of the memory to duplicate as a guint, whereas most memory functions take memory sizes as a gsize. This made it easy to accidentally pass a gsize to g_memdup(). For large values, that would lead to a silent truncation of the size from 64 to 32 bits, and result in a heap area being returned which is significantly smaller than what the caller expects. This can likely be exploited in various modules to cause a heap buffer overflow. Replace g_memdup() by the safer g_memdup2() wrapper. Signed-off-by: Philippe Mathieu-Daudé <phi...@redhat.com> --- qapi/qapi-clone-visitor.c | 16 ++++++++-------- qapi/qapi-visit-core.c | 6 ++++-- 2 files changed, 12 insertions(+), 10 deletions(-) diff --git a/qapi/qapi-clone-visitor.c b/qapi/qapi-clone-visitor.c index c45c5caa3b8..b014119d368 100644 --- a/qapi/qapi-clone-visitor.c +++ b/qapi/qapi-clone-visitor.c @@ -37,7 +37,7 @@ static bool qapi_clone_start_struct(Visitor *v, const char *name, void **obj, return true; } - *obj = g_memdup(*obj, size); + *obj = g_memdup2(*obj, size); qcv->depth++; return true; } @@ -65,8 +65,8 @@ static GenericList *qapi_clone_next_list(Visitor *v, GenericList *tail, QapiCloneVisitor *qcv = to_qcv(v); assert(qcv->depth); - /* Unshare the tail of the list cloned by g_memdup() */ - tail->next = g_memdup(tail->next, size); + /* Unshare the tail of the list cloned by g_memdup2() */ + tail->next = g_memdup2(tail->next, size); return tail->next; } @@ -83,7 +83,7 @@ static bool qapi_clone_type_int64(Visitor *v, const char *name, int64_t *obj, QapiCloneVisitor *qcv = to_qcv(v); assert(qcv->depth); - /* Value was already cloned by g_memdup() */ + /* Value was already cloned by g_memdup2() */ return true; } @@ -93,7 +93,7 @@ static bool qapi_clone_type_uint64(Visitor *v, const char *name, QapiCloneVisitor *qcv = to_qcv(v); assert(qcv->depth); - /* Value was already cloned by g_memdup() */ + /* Value was already cloned by g_memdup2() */ return true; } @@ -103,7 +103,7 @@ static bool qapi_clone_type_bool(Visitor *v, const char *name, bool *obj, QapiCloneVisitor *qcv = to_qcv(v); assert(qcv->depth); - /* Value was already cloned by g_memdup() */ + /* Value was already cloned by g_memdup2() */ return true; } @@ -114,7 +114,7 @@ static bool qapi_clone_type_str(Visitor *v, const char *name, char **obj, assert(qcv->depth); /* - * Pointer was already cloned by g_memdup; create fresh copy. + * Pointer was already cloned by g_memdup2; create fresh copy. * Note that as long as qobject-output-visitor accepts NULL instead of * "", then we must do likewise. However, we want to obey the * input visitor semantics of never producing NULL when the empty @@ -130,7 +130,7 @@ static bool qapi_clone_type_number(Visitor *v, const char *name, double *obj, QapiCloneVisitor *qcv = to_qcv(v); assert(qcv->depth); - /* Value was already cloned by g_memdup() */ + /* Value was already cloned by g_memdup2() */ return true; } diff --git a/qapi/qapi-visit-core.c b/qapi/qapi-visit-core.c index a641adec51e..ebabe63b6ea 100644 --- a/qapi/qapi-visit-core.c +++ b/qapi/qapi-visit-core.c @@ -413,8 +413,10 @@ bool visit_type_enum(Visitor *v, const char *name, int *obj, case VISITOR_OUTPUT: return output_type_enum(v, name, obj, lookup, errp); case VISITOR_CLONE: - /* nothing further to do, scalar value was already copied by - * g_memdup() during visit_start_*() */ + /* + * nothing further to do, scalar value was already copied by + * g_memdup2() during visit_start_*() + */ return true; case VISITOR_DEALLOC: /* nothing to deallocate for a scalar */ -- 2.31.1