On 9/3/21 1:16 PM, Daniel P. Berrangé wrote: > On Fri, Sep 03, 2021 at 01:06:36PM +0200, Philippe Mathieu-Daudé wrote: >> 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 e71e8cc0355 >> "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 <[email protected]> >> Signed-off-by: Philippe Mathieu-Daudé <[email protected]> >> --- >> include/glib-compat.h | 36 ++++++++++++++++++++++++++++++++++++ >> 1 file changed, 36 insertions(+) >> >> diff --git a/include/glib-compat.h b/include/glib-compat.h >> index 9e95c888f54..6577d9ab393 100644 >> --- a/include/glib-compat.h >> +++ b/include/glib-compat.h >> @@ -68,6 +68,42 @@ >> * 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 >> +} > > Close, but you missed the final piece of the puzzle > > #define g_memdup2(a) g_memdup2_qemu(a)
Doh :/ > Such that in all following patches you can use the normal "g_memdup2" > API. This means when we later update min glib, we just delete the > compat code here, and the callers don't need updates. Painful rebase in perspective...
