diff options
| author | Patrick Steinhardt <ps@pks.im> | 2017-05-22 12:53:44 +0200 |
|---|---|---|
| committer | Patrick Steinhardt <ps@pks.im> | 2017-06-06 09:33:53 +0200 |
| commit | 8a5e7aaecf7ce48dfab805debfc92458ab1112c5 (patch) | |
| tree | 8ee94a40b5dd461ff31ae001697cd6b3df545570 | |
| parent | dd0aa811dd329f5040c70f7aac514b3757eb2453 (diff) | |
| download | libgit2-8a5e7aaecf7ce48dfab805debfc92458ab1112c5.tar.gz | |
varint: fix computation for remaining buffer space
When encoding varints to a buffer, we want to remain sure that the
required buffer space does not exceed what is actually available. Our
current check does not do the right thing, though, in that it does not
honor that our `pos` variable counts the position down instead of up. As
such, we will require too much memory for small varints and not enough
memory for big varints.
Fix the issue by correctly calculating the required size as
`(sizeof(varint) - pos)`. Add a test which failed before.
| -rw-r--r-- | src/varint.c | 2 | ||||
| -rw-r--r-- | tests/core/encoding.c | 3 |
2 files changed, 4 insertions, 1 deletions
diff --git a/src/varint.c b/src/varint.c index 2f868607c..beac8c709 100644 --- a/src/varint.c +++ b/src/varint.c @@ -36,7 +36,7 @@ int git_encode_varint(unsigned char *buf, size_t bufsize, uintmax_t value) while (value >>= 7) varint[--pos] = 128 | (--value & 127); if (buf) { - if (bufsize < pos) + if (bufsize < (sizeof(varint) - pos)) return -1; memcpy(buf, varint + pos, sizeof(varint) - pos); } diff --git a/tests/core/encoding.c b/tests/core/encoding.c index 7d91720f4..a677afe2e 100644 --- a/tests/core/encoding.c +++ b/tests/core/encoding.c @@ -29,6 +29,9 @@ void test_core_encoding__encode(void) cl_assert(git_encode_varint(buf, 100, 65) == 1); cl_assert(buf[0] == 'A'); + cl_assert(git_encode_varint(buf, 1, 1) == 1); + cl_assert(!memcmp(buf, "\x01", 1)); + cl_assert(git_encode_varint(buf, 100, 267869656) == 4); cl_assert(!memcmp(buf, "\xfe\xdc\xbaX", 4)); |