Fix overflow in memcpy

[npes87184]

In function ‘memcpy’,                             
    inlined from ‘control_msg_serialize.constprop’ at ../app/src/control_msg.c:77:5,
    inlined from ‘run_controller’ at ../app/src/controller.c:69:12:
/usr/include/x86_64-linux-gnu/bits/string_fortified.h:34:10: warning: ‘__builtin___memcpy_chk’ writing 262138 bytes into a region of
 size 262130 overflows the destination [-Wstringop-overflow=]
   return __builtin___memcpy_chk (__dest, __src, __len, __bos0 (__dest));
          ^

When serialize CONTROL_MSG_TYPE_SET_CLIPBOARD event, it did not consider the size of sequence which is 8 bytes. So that the buffer size is not enough for memcpy.

[rom1v]

LGTM 👍

How did you detect it in practice? It may occur only on very specific text size...

[npes87184]

It was detected by compiler. 😉

[rom1v]

Which compiler? I tested with both gcc and clang, I don't get this warning. Any specific options?

[rom1v]

Merged:

• daa06ab
• d80bc25

I added a unit test: ae90ef2

[npes87184]

Which compiler? I tested with both gcc and clang, I don't get this warning. Any specific options?

I use gcc.

The Meson build system
Version: 0.55.3
Source dir: /home/yclin/scrcpy
Build dir: /home/yclin/scrcpy/x
Build type: native build
Project name: scrcpy
Project version: 1.21
C compiler for the host machine: cc (gcc 7.5.0 "cc (Ubuntu 7.5.0-3ubuntu1~18.04) 7.5.0")
C linker for the host machine: cc ld.bfd 2.30
Host machine cpu family: x86_64
Host machine cpu: x86_64
Found pkg-config: /usr/bin/pkg-config (0.29.1)
Run-time dependency libavformat found: YES 57.83.100
Run-time dependency libavcodec found: YES 57.107.100
Run-time dependency libavutil found: YES 55.78.100
Run-time dependency sdl2 found: YES 2.0.17
Run-time dependency libavdevice found: YES 57.10.100
Run-time dependency libusb-1.0 found: YES 1.0.21
Checking for function "strdup" : YES 
Checking for function "asprintf" : YES 
Checking for function "vasprintf" : YES 
Header <sys/socket.h> has symbol "SOCK_CLOEXEC" : YES 
Configuring config.h using configuration
Program ./scripts/build-wrapper.sh found: YES
Build targets in project: 3

Found ninja-1.8.2 at /usr/bin/ninja

The detection option is -Wstringop-overflow=.

Would it relate to the meson?