Invalid memcpy inside SDL_GestureDelTouch

[SDLBugzilla]

This bug report was migrated from our old Bugzilla tracker.

These attachments are available in the static archive:

• src/events/SDL_gesture.c: Patch proposal (faced89ea2f204dc28430558f5e754d7def7145f.patch, text/plain, 2021-01-10 13:11:34 +0000, 920 bytes)

Reported in version: HG 2.1
Reported for operating system, platform: Android (All), Other

Comments on the original bug report:

On 2021-01-10 13:11:34 +0000, Yuki Okumura wrote:

Created attachment 4655
src/events/SDL_gesture.c: Patch proposal

(Reported as: spurious/SDL-mirror#14 )

In function SDL_GestureDelTouch(), when deleting the final entry it might do overlapping memcpy because it might do:

SDL_memcpy(&SDL_gestureTouch[0], &SDL_gestureTouch[0], sizeof(SDL_gestureTouch[i]));

memcpy should not be used for overlapping region, but anyway, it does not need to be done.

Attached is @dmikushin's patch that adds check and skip memcpy when removing the final entry.

On 2021-01-10 21:22:46 +0000, Sylvain wrote:

Thanks, added in :
https://hg.libsdl.org/SDL/rev/17d911637a65

slightly differently: checking: (i != SDL_numGestureTouches)