a guest Oct 23rd, 2019 71 Never
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- To reproduce this bug the file must be in an OverlayFS mount
- Reproduced on:
- - linux-image-4.4.0-159-generic/xenial-updates,xenial-security,now 4.4.0-159.187 amd64
- - linux-image-4.4.0-165-generic/xenial-updates,xenial-security,now 4.4.0-165.193 amd64
- Install packages `libacl1-dev`, `build-essential`, and `gcc`.
- Included is a C program that reproduces the bug and two scripts. Run them in order.
- - `make-overlay.sh`: creates directories in /tmp and mounts /tmp/overlay as an overlay filesystem
- - `test.sh`: compiles the c program and executes it. additionally attempts to read the file and checks its permissions after the program exits.
- ubuntu@:~/ctr$ ./make-overlay.sh
- ubuntu@:~/ctr$ ./test.sh
- st_mode is 100644
- open failed: -1
- cat: /tmp/overlay/animal: Permission denied
- -rw-r--r-- 1 ubuntu ubuntu 0 Oct 4 19:40 /tmp/overlay/animal
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