It works for me. I suspect you might not have compiled sb-md5 from clean, and due to that bug I fixed in 2.26.9 which required a substantial refactoring, ASDF can now see that file was not up-to-date, when it couldn't see it earlier. Can you recompile this contrib from clean, either in place (by getting proper access rights) or in another directly from which you reinstall afterwards?
What does "compile from clean" mean? What's a way to *not* compile from clean?
Good question. When you build SBCL from source, update it then build again, does it remove the fasls in the contrib before to build them, or does it rely on ASDF for only compiling what's needed? In the latter case, this will may produce an "unclean" installation. Then, because sb-md5.asd was recently updated, and ASDF now (since 2.26.21) sees that as requiring .fasls to be updated (in case the dependencies have changed in a crucial way). If you clean.sh then make.sh your SBCL, it should all work.
Another explanation would be if the installation process of SBCL does not preserve timestamps, in which case ASDF will be very unhappy about it, which it wouldn't have been before if all fasl's happened to have been written at the same time as their lisp source file or before. I believe the tar and untar'ing by which things are installed preserves the timestamps, though (and was designed precisely for this purpose to be fulfilled portably without relying on GNU install).
FYI, here's a simplified way to reproduce it. From the ASDF source directory, with the latest checkout:
sbcl --non-interactive --no-userinit --load asdf.lisp --eval "(require :sb-md5)"
This lands in the debugger with the permissions error on three different SBCL installations of mine. Am I doing something wrong?
Note that indeed, one of my installations had to be recompiled that way, so whichever explanatino there is, I suppose the problem is pervasive with SBCL.
I don't know what to say, except: "if you've been installing SBCL from updated source, you might have to recompile some contrib".
—♯ƒ • François-René ÐVB Rideau •Reflection&Cybernethics• http://fare.tunes.org If all values are relative, then cannibalism is a matter of taste. — Leo Strauss