diff options
| author | Denton Liu <liu.denton@gmail.com> | 2020-05-19 13:54:00 +0300 |
|---|---|---|
| committer | Junio C Hamano <gitster@pobox.com> | 2020-05-25 02:26:00 +0300 |
| commit | b0df0c16ead4c5512d506dcbbdf31194d992803c (patch) | |
| tree | c2a5f0b8bfb8fd410c5b3b1217202d8f91e3df39 /builtin/fetch-pack.c | |
| parent | 0181b600a6deb66a346dbcbe8300cf9e2467ebbb (diff) | |
stateless-connect: send response end packet
Currently, remote-curl acts as a proxy and blindly forwards packets
between an HTTP server and fetch-pack. In the case of a stateless RPC
connection where the connection is terminated before the transaction is
complete, remote-curl will blindly forward the packets before waiting on
more input from fetch-pack. Meanwhile, fetch-pack will read the
transaction and continue reading, expecting more input to continue the
transaction. This results in a deadlock between the two processes.
This can be seen in the following command which does not terminate:
$ git -c protocol.version=2 clone https://github.com/git/git.git --shallow-since=20151012
Cloning into 'git'...
whereas the v1 version does terminate as expected:
$ git -c protocol.version=1 clone https://github.com/git/git.git --shallow-since=20151012
Cloning into 'git'...
fatal: the remote end hung up unexpectedly
Instead of blindly forwarding packets, make remote-curl insert a
response end packet after proxying the responses from the remote server
when using stateless_connect(). On the RPC client side, ensure that each
response ends as described.
A separate control packet is chosen because we need to be able to
differentiate between what the remote server sends and remote-curl's
control packets. By ensuring in the remote-curl code that a server
cannot send response end packets, we prevent a malicious server from
being able to perform a denial of service attack in which they spoof a
response end packet and cause the described deadlock to happen.
Reported-by: Force Charlie <charlieio@outlook.com>
Helped-by: Jeff King <peff@peff.net>
Signed-off-by: Denton Liu <liu.denton@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
Diffstat (limited to 'builtin/fetch-pack.c')
| -rw-r--r-- | builtin/fetch-pack.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/builtin/fetch-pack.c b/builtin/fetch-pack.c index 4771100072..94b0c89b82 100644 --- a/builtin/fetch-pack.c +++ b/builtin/fetch-pack.c @@ -224,7 +224,7 @@ int cmd_fetch_pack(int argc, const char **argv, const char *prefix) version = discover_version(&reader); switch (version) { case protocol_v2: - get_remote_refs(fd[1], &reader, &ref, 0, NULL, NULL); + get_remote_refs(fd[1], &reader, &ref, 0, NULL, NULL, args.stateless_rpc); break; case protocol_v1: case protocol_v0: |