fix(lfs): reject unknown SSH LFS sub-verbs to prevent auth bypass (#38008) (#38015)

This commit is contained in:
Giteabot
2026-06-06 13:07:06 -07:00
committed by GitHub
parent 603c8ece00
commit 8f4b7ebbf6
2 changed files with 70 additions and 9 deletions
+14 -9
View File
@@ -113,23 +113,25 @@ func handleCliResponseExtra(extra private.ResponseExtra) error {
return nil
}
func getAccessMode(verb, lfsVerb string) perm.AccessMode {
// getAccessMode maps an SSH git/LFS verb to the access mode it requires, with
// ok=false for an unrecognised verb. Callers MUST reject the request when ok is
// false: AccessModeNone would otherwise pass the `userMode < mode` permission
// check in routers/private/serv.go and grant access.
func getAccessMode(verb, lfsVerb string) (mode perm.AccessMode, ok bool) {
switch verb {
case git.CmdVerbUploadPack, git.CmdVerbUploadArchive:
return perm.AccessModeRead
return perm.AccessModeRead, true
case git.CmdVerbReceivePack:
return perm.AccessModeWrite
return perm.AccessModeWrite, true
case git.CmdVerbLfsAuthenticate, git.CmdVerbLfsTransfer:
switch lfsVerb {
case git.CmdSubVerbLfsUpload:
return perm.AccessModeWrite
return perm.AccessModeWrite, true
case git.CmdSubVerbLfsDownload:
return perm.AccessModeRead
return perm.AccessModeRead, true
}
}
// should be unreachable
setting.PanicInDevOrTesting("unknown verb: %s %s", verb, lfsVerb)
return perm.AccessModeNone
return perm.AccessModeNone, false
}
func runServ(ctx context.Context, c *cli.Command) error {
@@ -247,7 +249,10 @@ func runServ(ctx context.Context, c *cli.Command) error {
}
}
requestedMode := getAccessMode(verb, lfsVerb)
requestedMode, ok := getAccessMode(verb, lfsVerb)
if !ok {
return fail(ctx, "Unknown git command", "Unknown git command %s %s", verb, lfsVerb)
}
results, extra := private.ServCommand(ctx, keyID, username, reponame, requestedMode, verb, lfsVerb)
if extra.HasError() {