vcs-svn: cap number of bytes read from sliding view
Introduce a "max_off" field in struct sliding_view, roughly representing a maximum number of bytes that can be read from "file". If it is set to a nonnegative integer, a call to move_window() attempting to put the right endpoint beyond that offset will return an error instead. The idea is to use this when applying Subversion-format deltas to prevent reads past the end of the preimage (which has known length). Without such a check, corrupt deltas would cause svn-fe to block indefinitely when data in the input pipe is exhausted. Inspired-by: Ramkumar Ramachandra <artagnon@gmail.com> Signed-off-by: Jonathan Nieder <jrnieder@gmail.com>
Jonathan Nieder committed
May 27, 2011 at 04:07 UTC
fbdd4f6fb477885e4bf81658e02c3542a861c695
3 files changed
+5
-2
test-svn-fe.c
+1
-1
@@ -15,7 +15,7 @@ static int apply_delta(int argc, char *argv[])
15
{
16
struct line_buffer preimage = LINE_BUFFER_INIT;
17
struct line_buffer delta = LINE_BUFFER_INIT;
18
- struct sliding_view preimage_view = SLIDING_VIEW_INIT(&preimage);
18
+ struct sliding_view preimage_view = SLIDING_VIEW_INIT(&preimage, -1);
19
20
if (argc != 5)
21
usage(test_svnfe_usage);
vcs-svn/sliding_window.c
+2
@@ -54,6 +54,8 @@ int move_window(struct sliding_view *view, off_t off, size_t width)
54
return -1;
55
if (off < view->off || off + width < view->off + view->width)
56
return error("invalid delta: window slides left");
57
+ if (view->max_off >= 0 && view->max_off < off + width)
58
+ return error("delta preimage ends early");
59
60
file_offset = view->off + view->buf.len;
61
if (off < file_offset) {
vcs-svn/sliding_window.h
+2
-1
@@ -7,10 +7,11 @@ struct sliding_view {
7
struct line_buffer *file;
8
off_t off;
9
size_t width;
10
+ off_t max_off; /* -1 means unlimited */
11
struct strbuf buf;
12
};
13
13
-#define SLIDING_VIEW_INIT(input) { (input), 0, 0, STRBUF_INIT }
14
+#define SLIDING_VIEW_INIT(input, len) { (input), 0, 0, (len), STRBUF_INIT }
15
16
extern int move_window(struct sliding_view *view, off_t off, size_t width);
17