git-commit-vandalism/t/t5530-upload-pack-error.sh
Daniel Duvall fb3d1a083f upload-pack: allow stateless client EOF just prior to haves
During stateless packfile negotiation where a depth is given, stateless
RPC clients (e.g. git-remote-curl) will send multiple upload-pack
requests with the first containing only the
wants/shallows/deepens/filters and the subsequent containing haves/done.

When upload-pack handles such requests, entering get_common_commits
without checking whether the client has hung up can result in unexpected
EOF during the negotiation loop and a die() with message "fatal: the
remote end hung up unexpectedly".

Real world effects include:

 - A client speaking to git-http-backend via a server that doesn't check
   the exit codes of CGIs (e.g. mod_cgi) doesn't know and doesn't care
   about the fatal. It continues to process the response body as normal.

 - A client speaking to a server that does check the exit code and
   returns an errant HTTP status as a result will fail with the message
   "error: RPC failed; HTTP 500 curl 22 The requested URL returned error:
   500."

 - Admins running servers that surface the failure must workaround it by
   patching code that handles execution of git-http-backend to ignore exit
   codes or take other heuristic approaches.

 - Admins may have to deal with "hung up unexpectedly" log spam related
   to the failures even in cases where the exit code isn't surfaced as an
   HTTP server-side error status.

To avoid these EOF related fatals, have upload-pack gently peek for an
EOF between the sending of shallow/unshallow lines (followed by flush)
and the reading of client haves. If the client has hung up at this
point, exit normally.

Signed-off-by: Daniel Duvall <dan@mutual.io>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2020-10-30 21:18:10 -07:00

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#!/bin/sh
test_description='errors in upload-pack'
. ./test-lib.sh
D=$(pwd)
corrupt_repo () {
object_sha1=$(git rev-parse "$1") &&
ob=$(expr "$object_sha1" : "\(..\)") &&
ject=$(expr "$object_sha1" : "..\(..*\)") &&
rm -f ".git/objects/$ob/$ject"
}
test_expect_success 'setup and corrupt repository' '
echo file >file &&
git add file &&
git rev-parse :file &&
git commit -a -m original &&
test_tick &&
echo changed >file &&
git commit -a -m changed &&
corrupt_repo HEAD:file
'
test_expect_success 'fsck fails' '
test_must_fail git fsck
'
test_expect_success 'upload-pack fails due to error in pack-objects packing' '
head=$(git rev-parse HEAD) &&
hexsz=$(test_oid hexsz) &&
printf "%04xwant %s\n00000009done\n0000" \
$(($hexsz + 10)) $head >input &&
test_must_fail git upload-pack . <input >/dev/null 2>output.err &&
test_i18ngrep "unable to read" output.err &&
test_i18ngrep "pack-objects died" output.err
'
test_expect_success 'corrupt repo differently' '
git hash-object -w file &&
corrupt_repo HEAD^^{tree}
'
test_expect_success 'fsck fails' '
test_must_fail git fsck
'
test_expect_success 'upload-pack fails due to error in rev-list' '
printf "%04xwant %s\n%04xshallow %s00000009done\n0000" \
$(($hexsz + 10)) $(git rev-parse HEAD) \
$(($hexsz + 12)) $(git rev-parse HEAD^) >input &&
test_must_fail git upload-pack . <input >/dev/null 2>output.err &&
grep "bad tree object" output.err
'
test_expect_success 'upload-pack fails due to bad want (no object)' '
printf "%04xwant %s multi_ack_detailed\n00000009done\n0000" \
$(($hexsz + 29)) $(test_oid deadbeef) >input &&
test_must_fail git upload-pack . <input >output 2>output.err &&
grep "not our ref" output.err &&
grep "ERR" output &&
! grep multi_ack_detailed output.err
'
test_expect_success 'upload-pack fails due to bad want (not tip)' '
oid=$(echo an object we have | git hash-object -w --stdin) &&
printf "%04xwant %s multi_ack_detailed\n00000009done\n0000" \
$(($hexsz + 29)) "$oid" >input &&
test_must_fail git upload-pack . <input >output 2>output.err &&
grep "not our ref" output.err &&
grep "ERR" output &&
! grep multi_ack_detailed output.err
'
test_expect_success 'upload-pack fails due to error in pack-objects enumeration' '
printf "%04xwant %s\n00000009done\n0000" \
$((hexsz + 10)) $(git rev-parse HEAD) >input &&
test_must_fail git upload-pack . <input >/dev/null 2>output.err &&
grep "bad tree object" output.err &&
grep "pack-objects died" output.err
'
test_expect_success 'upload-pack tolerates EOF just after stateless client wants' '
test_commit initial &&
head=$(git rev-parse HEAD) &&
{
packetize "want $head" &&
packetize "shallow $head" &&
packetize "deepen 1" &&
printf "0000"
} >request &&
printf "0000" >expect &&
git upload-pack --stateless-rpc . <request >actual &&
test_cmp expect actual
'
test_expect_success 'create empty repository' '
mkdir foo &&
cd foo &&
git init
'
test_expect_success 'fetch fails' '
test_must_fail git fetch .. master
'
test_done