Johannes Schindelin <johannes.schindelin@xxxxxx> writes:
> So far, we assumed that the buffer is NUL terminated, but this is not
> a safe assumption, now that we opened the fsck_object() API to pass a
> buffer directly.
>
> So let's make sure that there is at least an empty line in the buffer.
> That way, our checks would fail if the empty line was encountered
> prematurely, and consequently we can get away with the current string
> comparisons even with non-NUL-terminated buffers are passed to
> fsck_object().
>
> Signed-off-by: Johannes Schindelin <johannes.schindelin@xxxxxx>
> ---
Heh, I probably should have read this one before commenting on 2/6.
It makes me feel somewhat uneasy to insist that there must be a
blank line in the commit object, even though from the very first
implementation of "commit-tree" I think we have always had a blank
there at the end of the header, even when you feed nothing as the
message to it.
I think the new check is OK, but the message should be s/empty
line/end of header/ or something. It is not like we require an
empty line in the log message proper.
> fsck.c | 23 +++++++++++++++++++++++
> 1 file changed, 23 insertions(+)
>
> diff --git a/fsck.c b/fsck.c
> index dd77628..db6aaa4 100644
> --- a/fsck.c
> +++ b/fsck.c
> @@ -237,6 +237,26 @@ static int fsck_tree(struct tree *item, int strict, fsck_error error_func)
> return retval;
> }
>
> +static int must_have_empty_line(const void *data, unsigned long size,
> + struct object *obj, fsck_error error_func)
> +{
> + const char *buffer = (const char *)data;
> + int i;
> +
> + for (i = 0; i < size; i++) {
> + switch (buffer[i]) {
> + case '\0':
> + return error_func(obj, FSCK_ERROR,
> + "invalid message: NUL at offset %d", i);
> + case '\n':
> + if (i + 1 < size && buffer[i + 1] == '\n')
> + return 0;
> + }
> + }
> +
> + return error_func(obj, FSCK_ERROR, "invalid buffer: missing empty line");
> +}
> +
> static int fsck_ident(const char **ident, struct object *obj, fsck_error error_func)
> {
> char *end;
> @@ -284,6 +304,9 @@ static int fsck_commit_buffer(struct commit *commit, const char *buffer,
> unsigned parent_count, parent_line_count = 0;
> int err;
>
> + if (must_have_empty_line(buffer, size, &commit->object, error_func))
> + return -1;
> +
> if (!skip_prefix(buffer, "tree ", &buffer))
> return error_func(&commit->object, FSCK_ERROR, "invalid format - expected 'tree' line");
> if (get_sha1_hex(buffer, tree_sha1) || buffer[40] != '\n')
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