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Bug 5456

Summary: Invalid memcpy inside SDL_GestureDelTouch
Product: SDL Reporter: Yuki Okumura <mjt>
Component: eventsAssignee: Sam Lantinga <slouken>
Status: RESOLVED FIXED QA Contact: Sam Lantinga <slouken>
Severity: normal    
Priority: P2 CC: sylvain.becker
Version: HG 2.1   
Hardware: Other   
OS: Android (All)   
Attachments: src/events/SDL_gesture.c: Patch proposal

Description Yuki Okumura 2021-01-10 13:11:34 UTC 
Created attachment 4655 [details]
src/events/SDL_gesture.c: Patch proposal

(Reported as: https://github.com/spurious/SDL-mirror/pull/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.
Comment 1 Sylvain 2021-01-10 21:22:46 UTC 
Thanks, added in :
https://hg.libsdl.org/SDL/rev/17d911637a65

slightly differently: checking: (i != SDL_numGestureTouches)