GHSA-2pxw-r47w-4p8c

### Impact An attacker can use crafted requests to bypass metadata bucket name checking and put an object into any bucket while processing `PostPolicyBucket`. To carry out this attack, the attacker requires credentials with `arn:aws:s3:::*` permission, as well as enabled Console API access.

### Patches ``` commit 67f4ba154a27a1b06e48bfabda38355a010dfca5 Author: Aditya Manthramurthy <donatello@users.noreply.github.com> Date: Sun Mar 19 21:15:20 2023 -0700

fix: post policy request security bypass (#16849) ```

### Workarounds Browser API access must be enabled turning off `MINIO_BROWSER=off` allows for this workaround.

### References The vulnerable code: ```go // minio/cmd/generic-handlers.go func setRequestValidityHandler(h http.Handler) http.Handler { return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) { // ... // For all other requests reject access to reserved buckets bucketName, _ := request2BucketObjectName(r) if isMinioReservedBucket(bucketName) || isMinioMetaBucket(bucketName) { if !guessIsRPCReq(r) && !guessIsBrowserReq(r) && !guessIsHealthCheckReq(r) && !guessIsMetricsReq(r) && !isAdminReq(r) && !isKMSReq(r) { if ok { tc.FuncName = "handler.ValidRequest" tc.ResponseRecorder.LogErrBody = true } writeErrorResponse(r.Context(), w, errorCodes.ToAPIErr(ErrAllAccessDisabled), r.URL) return } } // ... ```