TransferManager allocates a lot of memory (50 MiB by default), and it
might leak but I'm not sure about that. In any case it was causing
OOMs in hydra-queue-runner. So allocate only one TransferManager per
S3BinaryCacheStore.
Hopefully fixes https://github.com/NixOS/hydra/issues/586.
This callback is executed on a different thread, so exceptions thrown
from the callback are not caught:
Aug 08 16:25:48 chef hydra-queue-runner[11967]: terminate called after throwing an instance of 'nix::Error'
Aug 08 16:25:48 chef hydra-queue-runner[11967]: what(): AWS error: failed to upload 's3://nix-cache/19dbddlfb0vp68g68y19p9fswrgl0bg7.ls'
Therefore, just check the transfer status after it completes. Also
include the S3 error message in the exception.
This didn't work anymore since decompression was only done in the
non-coroutine case.
Decompressors are now sinks, just like compressors.
Also fixed a bug in bzip2 API handling (we have to handle BZ_RUN_OK
rather than BZ_OK), which we didn't notice because there was a missing
'throw':
if (ret != BZ_OK)
CompressionError("error while compressing bzip2 file");
It adds a new operation, cmdAddToStoreNar, that does the same thing as
the corresponding nix-daemon operation, i.e. call addToStore(). This
replaces cmdImportPaths, which has the major issue that it sends the
NAR first and the store path second, thus requiring us to store the
incoming NAR either in memory or on disk until we decide what to do
with it.
For example, this reduces the memory usage of
$ nix copy --to 'ssh://localhost?remote-store=/tmp/nix' /nix/store/95cwv4q54dc6giaqv6q6p4r02ia2km35-blender-2.79
from 267 MiB to 12 MiB.
Probably fixes#1988.
In EvalState::checkSourcePath, the path is checked against the list of
allowed paths first and later it's checked again *after* resolving
symlinks.
The resolving of the symlinks is done via canonPath, which also strips
out "../" and "./". However after the canonicalisation the error message
pointing out that the path is not allowed prints the symlink target in
the error message.
Even if we'd suppress the message, symlink targets could still be leaked
if the symlink target doesn't exist (in this case the error is thrown in
canonPath).
So instead, we now do canonPath() without symlink resolving first before
even checking against the list of allowed paths and then later do the
symlink resolving and checking the allowed paths again.
The first call to canonPath() should get rid of all the "../" and "./",
so in theory the only way to leak a symlink if the attacker is able to
put a symlink in one of the paths allowed by restricted evaluation mode.
For the latter I don't think this is part of the threat model, because
if the attacker can write to that path, the attack vector is even
larger.
Signed-off-by: aszlig <aszlig@nix.build>
This particular `shell` variable wasn't used, since a new one was
declared in the only side of the `if` branch that used a `shell`
variable.
It could realistically confuse developers thinking it could use `$SHELL`
under some situations.
Samuel Dionne-Riel
Linus Heckemann