proxmox-mirrors/libgit2
1
0
Fork 0
mirror of https://git.proxmox.com/git/libgit2 synced 2025-05-02 21:34:15 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

varint: fix computation for remaining buffer space

Browse Source 
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.
This commit is contained in:
Patrick Steinhardt 2017-05-22 12:53:44 +02:00
parent dd0aa811dd
commit 8a5e7aaecf
2 changed files with 4 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/varint.c
View File

@ -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);
}

3
tests/core/encoding.c
View File

@ -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));