Re: [PATCH v2] net/tap-win32: Fix gcc 14 format truncation errors

["Philippe Mathieu-Daudé" <philmd@linaro.org>]

On 8/10/24 17:28, Bernhard Beschow wrote:
> The patch fixes the following errors generated by GCC 14.2:
> 
> ../src/net/tap-win32.c:343:19: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 176 [-Werror=format-truncation=]
>    343 |              "%s\\%s\\Connection",
>        |                   ^~
>    344 |              NETWORK_CONNECTIONS_KEY, enum_name);
>        |                                       ~~~~~~~~~
> 
> ../src/net/tap-win32.c:341:9: note: 'snprintf' output between 92 and 347 bytes into a destination of size 256
>    341 |         snprintf(connection_string,
>        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~
>    342 |              sizeof(connection_string),
>        |              ~~~~~~~~~~~~~~~~~~~~~~~~~~
>    343 |              "%s\\%s\\Connection",
>        |              ~~~~~~~~~~~~~~~~~~~~~
>    344 |              NETWORK_CONNECTIONS_KEY, enum_name);
>        |              ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
> 
> ../src/net/tap-win32.c:242:58: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 178 [-Werror=format-truncation=]
>    242 |         snprintf (unit_string, sizeof(unit_string), "%s\\%s",
>        |                                                          ^~
>    243 |                   ADAPTER_KEY, enum_name);
>        |                                ~~~~~~~~~
> 
> ../src/net/tap-win32.c:242:9: note: 'snprintf' output between 79 and 334 bytes into a destination of size 256
>    242 |         snprintf (unit_string, sizeof(unit_string), "%s\\%s",
>        |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    243 |                   ADAPTER_KEY, enum_name);
>        |                   ~~~~~~~~~~~~~~~~~~~~~~~
> 
> ../src/net/tap-win32.c:620:52: error: '%s' directive output may be truncated writing up to 255 bytes into a region of size 245 [-Werror=format-truncation=]
>    620 |     snprintf (device_path, sizeof(device_path), "%s%s%s",
>        |                                                    ^~
>    621 |               USERMODEDEVICEDIR,
>    622 |               device_guid,
>        |               ~~~~~~~~~~~
> ../src/net/tap-win32.c:620:5: note: 'snprintf' output between 16 and 271 bytes into a destination of size 256
>    620 |     snprintf (device_path, sizeof(device_path), "%s%s%s",
>        |     ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>    621 |               USERMODEDEVICEDIR,
>        |               ~~~~~~~~~~~~~~~~~~
>    622 |               device_guid,
>        |               ~~~~~~~~~~~~
>    623 |               TAPSUFFIX);
>        |               ~~~~~~~~~~
> 
> Signed-off-by: Bernhard Beschow <shentey@gmail.com>
> Resolves: https://gitlab.com/qemu-project/qemu/-/issues/2607
> Cc: qemu-stable@nongnu.org
> 
> --

---

Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>

> 
> This patch was just compile-tested (which fixes my issue). Testing TAP
> networking under Windows apparently requires extra drivers which I don't want to
> install (not my computer). So it would be nice if someone could give this patch
> a test ride. Thanks!
> 
> Changes since v1:
> * Use g_autofree and g_strdup_printf() rather than fixed size arrays (Peter)
> ---
>   net/tap-win32.c | 15 ++++++---------
>   1 file changed, 6 insertions(+), 9 deletions(-)