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| author | Jonathan Nieder <jrnieder@gmail.com> | 2011-05-27 04:07:44 -0500 |
|---|---|---|
| committer | Jonathan Nieder <jrnieder@gmail.com> | 2011-06-15 02:15:22 -0500 |
| commit | fbdd4f6fb477885e4bf81658e02c3542a861c695 (patch) | |
| tree | 4284cbc220ef15c28474e3203448fd60397c68d5 | |
| parent | b747e5675db5e26292c942146a25e1c26440c5f7 (diff) | |
| download | git-fbdd4f6fb477885e4bf81658e02c3542a861c695.tar.gz | |
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>
| -rw-r--r-- | test-svn-fe.c | 2 | ||||
| -rw-r--r-- | vcs-svn/sliding_window.c | 2 | ||||
| -rw-r--r-- | vcs-svn/sliding_window.h | 3 |
3 files changed, 5 insertions, 2 deletions
diff --git a/test-svn-fe.c b/test-svn-fe.c index a0276260eb..332a5f711d 100644 --- a/test-svn-fe.c +++ b/test-svn-fe.c @@ -15,7 +15,7 @@ static int apply_delta(int argc, char *argv[]) { struct line_buffer preimage = LINE_BUFFER_INIT; struct line_buffer delta = LINE_BUFFER_INIT; - struct sliding_view preimage_view = SLIDING_VIEW_INIT(&preimage); + struct sliding_view preimage_view = SLIDING_VIEW_INIT(&preimage, -1); if (argc != 5) usage(test_svnfe_usage); diff --git a/vcs-svn/sliding_window.c b/vcs-svn/sliding_window.c index 1b8d9875ed..1bac7a4c7f 100644 --- a/vcs-svn/sliding_window.c +++ b/vcs-svn/sliding_window.c @@ -54,6 +54,8 @@ int move_window(struct sliding_view *view, off_t off, size_t width) return -1; if (off < view->off || off + width < view->off + view->width) return error("invalid delta: window slides left"); + if (view->max_off >= 0 && view->max_off < off + width) + return error("delta preimage ends early"); file_offset = view->off + view->buf.len; if (off < file_offset) { diff --git a/vcs-svn/sliding_window.h b/vcs-svn/sliding_window.h index ed0bfdd65c..b43a825cba 100644 --- a/vcs-svn/sliding_window.h +++ b/vcs-svn/sliding_window.h @@ -7,10 +7,11 @@ struct sliding_view { struct line_buffer *file; off_t off; size_t width; + off_t max_off; /* -1 means unlimited */ struct strbuf buf; }; -#define SLIDING_VIEW_INIT(input) { (input), 0, 0, STRBUF_INIT } +#define SLIDING_VIEW_INIT(input, len) { (input), 0, 0, (len), STRBUF_INIT } extern int move_window(struct sliding_view *view, off_t off, size_t width); |