[PATCH 3/3] receive-pack: allow a maximum input size to be specified
- From
Christian Couder <christian.couder@gmail.com>
- Date
- Aug 16, 2016, 08:17 UTC
- Message-ID
- <20160816081701.29949-4-chriscool@tuxfamily.org>
- In-Reply-To
- <20160816081701.29949-1-chriscool@tuxfamily.org>
From: Jeff King <peff@peff.net>
Receive-pack feeds its input to either index-pack or unpack-objects, which will happily accept as many bytes as a sender is willing to provide. Let's allow an arbitrary cutoff point where we will stop writing bytes to disk.
Cleaning up what has already been written to disk is a related problem that is not addressed by this patch.
The problem is that git-gc can clean up tmp_pack_* files after their grace time expired, but that may not be enough if someone tries to "git push" in a loop.
A simple fix is to call register_tempfile() in open_pack_file(), and just have index-pack clean up the file on its way out.
But there are harder cases. For instance, if somebody pushes a 500MB file, and there is a pre-receive hook that says "too big; I won't accept this". And then they push in a loop, the incoming pack has already been accepted into the repository by the time the pre-receive hook runs. It's not possible to just delete it, because we don't know if other simultaneous processes have started to depend on the objects.
Signed-off-by: Jeff King <peff@peff.net> Signed-off-by: Christian Couder <chriscool@tuxfamily.org> --- Documentation/config.txt | 5 +++++ Documentation/git-receive-pack.txt | 3 +++ builtin/receive-pack.c | 12 +++++++++++ t/t5546-push-limits.sh | 42 ++++++++++++++++++++++++++++++++++++++ 4 files changed, 62 insertions(+) create mode 100755 t/t5546-push-limits.sh
diff --git a/Documentation/config.txt b/Documentation/config.txt index 0bcb679..f5b6061 100644 --- a/Documentation/config.txt +++ b/Documentation/config.txt @@ -2517,6 +2517,11 @@ receive.unpackLimit:: especially on slow filesystems. If not set, the value of `transfer.unpackLimit` is used instead. +receive.maxsize:: + If the size of a pack file is larger than this limit, then + git-receive-pack will error out, instead of accepting the pack + file. If not set or set to 0, then the size is unlimited. + receive.denyDeletes:: If set to true, git-receive-pack will deny a ref update that deletes the ref. Use this to prevent such a ref deletion via a push. diff --git a/Documentation/git-receive-pack.txt b/Documentation/git-receive-pack.txt index 000ee8d..0ccd5fb 100644 --- a/Documentation/git-receive-pack.txt +++ b/Documentation/git-receive-pack.txt @@ -33,6 +33,9 @@ post-update hooks found in the Documentation/howto directory. option, which tells it if updates to a ref should be denied if they are not fast-forwards. +A number of other receive.* config options are available to tweak +its behavior, see linkgit:git-config[1]. + OPTIONS ------- <directory>:: diff --git a/builtin/receive-pack.c b/builtin/receive-pack.c index 92e1213..8c2943d 100644 --- a/builtin/receive-pack.c +++ b/builtin/receive-pack.c @@ -46,6 +46,7 @@ static int transfer_unpack_limit = -1; static int advertise_atomic_push = 1; static int advertise_push_options; static int unpack_limit = 100; +static off_t max_input_size; static int report_status; static int use_sideband; static int use_atomic; @@ -212,6 +213,11 @@ static int receive_pack_config(const char *var, const char *value, void *cb) return 0; } + if (strcmp(var, "receive.maxsize") == 0) { + max_input_size = git_config_int64(var, value); + return 0; + } + return git_default_config(var, value, cb); } @@ -1650,6 +1656,9 @@ static const char *unpack(int err_fd, struct shallow_info *si) if (fsck_objects) argv_array_pushf(&child.args, "--strict%s", fsck_msg_types.buf); + if (max_input_size) + argv_array_pushf(&child.args, "--max-input-size=%"PRIuMAX, + (uintmax_t)max_input_size); child.no_stdout = 1; child.err = err_fd; child.git_cmd = 1; @@ -1678,6 +1687,9 @@ static const char *unpack(int err_fd, struct shallow_info *si) fsck_msg_types.buf); if (!reject_thin) argv_array_push(&child.args, "--fix-thin"); + if (max_input_size) + argv_array_pushf(&child.args, "--max-input-size=%"PRIuMAX, + (uintmax_t)max_input_size); child.out = -1; child.err = err_fd; child.git_cmd = 1; diff --git a/t/t5546-push-limits.sh b/t/t5546-push-limits.sh new file mode 100755 index 0000000..b38d508 --- /dev/null +++ b/t/t5546-push-limits.sh @@ -0,0 +1,42 @@ +#!/bin/sh + +test_description='check input limits for pushing' +. ./test-lib.sh + +test_expect_success 'create remote repository' ' + git init --bare dest +' + +# Let's run tests with different unpack limits: 1 and 10 +# When the limit is 1, `git receive-pack` will call `git index-pack`. +# When the limit is 10, `git receive-pack` will call `git unpack-objects`. + +while read unpacklimit filesize filename +do + + test_expect_success "create known-size ($filesize bytes) commit '$filename'" ' + test-genrandom foo "$filesize" >"$filename" && + git add "$filename" && + test_commit "$filename" + ' + + test_expect_success "set unpacklimit to $unpacklimit" ' + git --git-dir=dest config receive.unpacklimit "$unpacklimit" + ' + + test_expect_success 'setting receive.maxsize to 512 rejects push' ' + git --git-dir=dest config receive.maxsize 512 && + test_must_fail git push dest HEAD + ' + + test_expect_success 'bumping limit to 4k allows push' ' + git --git-dir=dest config receive.maxsize 4k && + git push dest HEAD + ' + +done <<\EOF +1 1024 one-k-file +10 2048 two-k-file +EOF + +test_done
-- 2.10.0.rc0.3.g8535b4c