From 44d2aec6e8795ac22b9121b3d2ecf43589e8ecd2 Mon Sep 17 00:00:00 2001
From: Andrzej Hunt <andrzej@ahunt.org>
Date: Sun, 26 Sep 2021 15:58:33 +0000
Subject: [PATCH] connect: also update offset for features without values
parse_feature_value() takes an offset, and uses it to seek past the
point in features_list that we've already seen. However if the feature
being searched for does not specify a value, the offset is not
updated. Therefore if we call parse_feature_value() in a loop on a
value-less feature, we'll keep on parsing the same feature over and over
again. This usually isn't an issue: there's no point in using
next_server_feature_value() to search for repeated instances of the same
capability unless that capability typically specifies a value - but a
broken server could send a response that omits the value for a feature
even when we are expecting a value.
Therefore we add an offset update calculation for the no-value case,
which helps ensure that loops using next_server_feature_value() will
always terminate.
next_server_feature_value(), and the offset calculation, were first
added in 2.28 in 2c6a403d96 (connect: add function to parse multiple
v1 capability values, 2020-05-25).
Thanks to Peff for authoring the test.
Co-authored-by: Jeff King <peff@peff.net>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Andrzej Hunt <andrzej@ahunt.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
---
connect.c | 2 ++
t/t5704-protocol-violations.sh | 15 +++++++++++++++
2 files changed, 17 insertions(+)
diff --git a/connect.c b/connect.c
index 70b13389ba..71e8757e24 100644
--- a/connect.c
+++ b/connect.c
@@ -555,6 +555,8 @@ const char *parse_feature_value(const char *feature_list, const char *feature, i
if (!*value || isspace(*value)) {
if (lenp)
*lenp = 0;
+ if (offset)
+ *offset = found + len - feature_list;
return value;
}
/* feature with a value (e.g., "agent=git/1.2.3") */
diff --git a/t/t5704-protocol-violations.sh b/t/t5704-protocol-violations.sh
index 5c941949b9..bc393d7c31 100755
--- a/t/t5704-protocol-violations.sh
+++ b/t/t5704-protocol-violations.sh
@@ -32,4 +32,19 @@ test_expect_success 'extra delim packet in v2 fetch args' '
test_i18ngrep "expected flush after fetch arguments" err
'
+test_expect_success 'bogus symref in v0 capabilities' '
+ test_commit foo &&
+ oid=$(git rev-parse HEAD) &&
+ dst=refs/heads/foo &&
+ {
+ printf "%s HEAD\0symref object-format=%s symref=HEAD:%s\n" \
+ "$oid" "$GIT_DEFAULT_HASH" "$dst" |
+ test-tool pkt-line pack-raw-stdin &&
+ printf "0000"
+ } >input &&
+ git ls-remote --symref --upload-pack="cat input; read junk;:" . >actual &&
+ printf "ref: %s\tHEAD\n%s\tHEAD\n" "$dst" "$oid" >expect &&
+ test_cmp expect actual
+'
+
test_done