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glib-compat: Introduce g_memdup2() wrapper

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When experimenting raising GLIB_VERSION_MIN_REQUIRED to 2.68
(Fedora 34 provides GLib 2.68.1) we get:

  hw/virtio/virtio-crypto.c:245:24: error: 'g_memdup' is deprecated: Use 'g_memdup2' instead [-Werror,-Wdeprecated-declarations]
  ...

g_memdup() has been updated by g_memdup2() to fix eventual security
issues (size argument is 32-bit and could be truncated / wrapping).
GLib recommends to copy their static inline version of g_memdup2():
https://discourse.gnome.org/t/port-your-module-from-g-memdup-to-g-memdup2-now/5538

Our glib-compat.h provides a comment explaining how to deal with
these deprecated declarations (see commit e71e8cc035
"glib: enforce the minimum required version and warn about old APIs").

Following this comment suggestion, implement the g_memdup2_qemu()
wrapper to g_memdup2(), and use the safer equivalent inlined when
we are using pre-2.68 GLib.

Reported-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Message-Id: <20210903174510.751630-3-philmd@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
This commit is contained in:
Philippe Mathieu-Daudé 2021-09-03 19:44:44 +02:00 committed by Laurent Vivier
parent 036ef344b6
commit 2c674fada7
1 changed files with 37 additions and 0 deletions
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37
include/glib-compat.h
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@ -68,6 +68,43 @@
* without generating warnings.
*/
/*
* g_memdup2_qemu:
* @mem: (nullable): the memory to copy.
* @byte_size: the number of bytes to copy.
*
* Allocates @byte_size bytes of memory, and copies @byte_size bytes into it
* from @mem. If @mem is %NULL it returns %NULL.
*
* This replaces g_memdup(), which was prone to integer overflows when
* converting the argument from a #gsize to a #guint.
*
* This static inline version is a backport of the new public API from
* GLib 2.68, kept internal to GLib for backport to older stable releases.
* See https://gitlab.gnome.org/GNOME/glib/-/issues/2319.
*
* Returns: (nullable): a pointer to the newly-allocated copy of the memory,
* or %NULL if @mem is %NULL.
*/
static inline gpointer g_memdup2_qemu(gconstpointer mem, gsize byte_size)
{
#if GLIB_CHECK_VERSION(2, 68, 0)
return g_memdup2(mem, byte_size);
#else
gpointer new_mem;
if (mem && byte_size != 0) {
new_mem = g_malloc(byte_size);
memcpy(new_mem, mem, byte_size);
} else {
new_mem = NULL;
}
return new_mem;
#endif
}
#define g_memdup2(m, s) g_memdup2_qemu(m, s)
#if defined(G_OS_UNIX)
/*
* Note: The fallback implementation is not MT-safe, and it returns a copy of