"""A 45-second video for Fil-BIND: BIND 9 compiled with Fil-C. Render with ./render.sh, which writes ../fil-bind.mp4 and ../poster.png. It is 16:9 at 1920x1080 so that it plays full width on the page and on Twitter. As in the frame-coloring explainer, captions are a few words each and the pictures carry the argument; the page has the details and the sources. """ import os from manim import * PAPER = "#ffffff" INK = "#111111" MUTED = "#667078" FAINT = "#c9cdd1" ACC = "#9a3248" # corruption, the attacker's win AMB = "#d98a1c" # the neighbouring secret BLU = "#2f6fb3" # the pointer GRN = "#3d7a3d" # Fil-C SLOWDOWN = os.environ.get("FILBIND_SLOWDOWN", "5–6") config.background_color = PAPER config.pixel_width = 1920 config.pixel_height = 1080 config.frame_height = 8 config.frame_width = 8 * 16 / 9 TPL = TexTemplate( tex_compiler="xelatex", output_format=".xdv", documentclass=r"\documentclass[preview]{standalone}", ) TPL.add_to_preamble( r"\usepackage{fontspec}" "\n" r"\setmainfont{PublicSans}[Path=" + os.environ["PUBLIC_SANS"] + r"/, Extension=.otf," r" UprightFont=*-Regular, BoldFont=*-Bold]" "\n" r"\setmonofont{DejaVu Sans Mono}[Scale=MatchLowercase]" ) def T(s, size=30, color=INK, bold=False): return Tex(r"\textbf{" + s + "}" if bold else s, tex_template=TPL, font_size=size, color=color) def M(s, size=28, color=INK): return Tex(r"\texttt{" + s + "}", tex_template=TPL, font_size=size, color=color) def cell(color=MUTED, fill=None): return Square(0.62, color=color, stroke_width=2, fill_color=fill or PAPER, fill_opacity=1 if fill else 0) def pointer(color=BLU): tri = Triangle(color=color, fill_opacity=1, stroke_width=0).scale(0.16).rotate(PI) return VGroup(tri, T("p", 26, color, bold=True).next_to(tri, UP, 0.06)) def stop(text="Fil-C panic"): oct_ = RegularPolygon(8, color=ACC, fill_color=ACC, fill_opacity=1, stroke_width=0).scale(0.42).rotate(PI / 8) return VGroup(oct_, T("STOP", 18, PAPER, bold=True).move_to(oct_), T(text, 26, GRN, bold=True).next_to(oct_, RIGHT, 0.2)) class Explainer(Scene): cap = None def caption(self, s, color=INK, size=54): c = VGroup(*[T(line, size, color, bold=True) for line in s.split("\n")]).arrange(DOWN, buff=0.15) c.to_edge(UP, buff=0.5) if self.cap is None: self.play(FadeIn(c, shift=DOWN * 0.2), run_time=0.5) else: self.play(FadeOut(self.cap, shift=UP * 0.2), FadeIn(c, shift=UP * 0.2), run_time=0.5) self.cap = c def clear_all(self): self.play(*[FadeOut(m) for m in self.mobjects], run_time=0.5) self.cap = None def lanes(self): top = T("BIND", 34, MUTED, bold=True).move_to([-5.6, 0.9, 0]) bot = T("Fil-BIND", 34, GRN, bold=True).move_to([-5.6, -1.9, 0]) rule = DashedLine([-6.6, -0.5, 0], [6.6, -0.5, 0], color=FAINT, stroke_width=2) return top, bot, rule def construct(self): # 1. The news. cve = T("CVE-2026-94300", 120, ACC, bold=True) sub = T("BIND \\textperiodcentered{} memory corruption \\textperiodcentered{} potential remote code execution", 36, INK).next_to(cve, DOWN, 0.45) when = T("ISC advisory, 21 October 2026", 28, MUTED).next_to(sub, DOWN, 0.3) self.play(FadeIn(cve, scale=0.9), run_time=0.8) self.play(FadeIn(sub), FadeIn(when)) self.wait(1.6) self.play(FadeOut(cve), FadeOut(sub), FadeOut(when), run_time=0.5) # 2. Where it sits among this year's advisories. self.caption("37 BIND advisories since March") parts = [(6, "memory corruption", ACC), (11, "assertion exits", MUTED), (12, "resource exhaustion", MUTED), (8, "logic, poisoning", MUTED)] unit, x = 12.0 / 37, -6.0 segs, labs = VGroup(), VGroup() for n, name, color in parts: r = Rectangle(width=n * unit - 0.06, height=1.0, stroke_width=0, fill_color=color, fill_opacity=1 if color == ACC else 0.35) r.move_to([x + n * unit / 2, 0, 0]) segs.add(r) num = T(str(n), 48, PAPER if color == ACC else INK, bold=True).move_to(r) lab = T(name, 26, color if color == ACC else MUTED).next_to(r, DOWN, 0.25) labs.add(VGroup(num, lab)) x += n * unit self.play(LaggedStart(*[GrowFromEdge(s, LEFT) for s in segs], lag_ratio=0.25), run_time=1.2) self.play(LaggedStart(*[FadeIn(l) for l in labs], lag_ratio=0.15), run_time=0.8) self.caption("6 are memory-safety bugs", ACC) self.play(segs[1:].animate.set_fill(opacity=0.12), labs[1:].animate.set_opacity(0.35), Indicate(segs[0], color=ACC, scale_factor=1.05), run_time=0.8) self.wait(1.0) self.clear_all() # 3. Out of bounds: the write lands next door, or stops. self.caption("Write past the end") top, bot, rule = self.lanes() def row(y): buf = VGroup(*[cell() for _ in range(6)]).arrange(RIGHT, buff=0.06) key = VGroup(*[cell(AMB, "#f8e6cb") for _ in range(3)]).arrange(RIGHT, buff=0.06) VGroup(buf, key).arrange(RIGHT, buff=0.06).move_to([0.6, y, 0]) bl = T("buffer", 24, MUTED).next_to(buf, DOWN, 0.15) kl = T("key", 24, AMB, bold=True).next_to(key, DOWN, 0.15) return buf, key, VGroup(bl, kl) b1, k1, l1 = row(0.9) b2, k2, l2 = row(-1.9) bounds = BraceBetweenPoints(b2.get_corner(UL) + UP * 0.12, b2.get_corner(UR) + UP * 0.12, UP, color=GRN) bl = T("p's bounds", 24, GRN, bold=True).next_to(bounds, UP, 0.05) self.play(FadeIn(top), FadeIn(bot), Create(rule), FadeIn(b1), FadeIn(k1), FadeIn(l1), FadeIn(b2), FadeIn(k2), FadeIn(l2), run_time=0.6) p1 = pointer().next_to(b1[0], UP, 0.12) p2 = pointer().next_to(b2[0], UP, 0.12) self.play(FadeIn(p1), FadeIn(p2), GrowFromCenter(bounds), FadeIn(bl), run_time=0.5) self.play(FadeOut(bounds), FadeOut(bl), run_time=0.3) for i in range(6): self.play(p1.animate.next_to(b1[i], UP, 0.12), p2.animate.next_to(b2[i], UP, 0.12), b1[i].animate.set_fill(BLU, 0.5), b2[i].animate.set_fill(BLU, 0.5), run_time=0.22) self.play(p1.animate.next_to(k1[0], UP, 0.12), p2.animate.next_to(k2[0], UP, 0.12), run_time=0.3) hit = T("key overwritten", 30, ACC, bold=True).next_to(k1, RIGHT, 0.35) st = stop().next_to(k2, RIGHT, 0.35) self.play(k1[0].animate.set_fill(ACC, 1).set_stroke(ACC), FadeIn(hit), Indicate(k2[0], color=ACC), FadeIn(st, scale=0.8), run_time=0.7) self.wait(1.4) self.clear_all() # 4. Use after free: the pointer reads the next occupant, or stops. self.caption("Use after free") top, bot, rule = self.lanes() def obj(y, name, color): box = RoundedRectangle(corner_radius=0.12, width=2.8, height=1.0, color=color, stroke_width=3, fill_color=color, fill_opacity=0.15).move_to([0.6, y, 0]) return VGroup(box, T(name, 32, color, bold=True).move_to(box)) q1, q2 = obj(0.9, "query", BLU), obj(-1.9, "query", BLU) def side_pointer(): tri = Triangle(color=BLU, fill_opacity=1, stroke_width=0).scale(0.16).rotate(-PI / 2) return VGroup(T("p", 26, BLU, bold=True), tri).arrange(RIGHT, buff=0.08) p1 = side_pointer().next_to(q1, LEFT, 0.3) p2 = side_pointer().next_to(q2, LEFT, 0.3) self.play(FadeIn(top), FadeIn(bot), Create(rule), FadeIn(q1), FadeIn(q2), FadeIn(p1), FadeIn(p2), run_time=0.6) fr = M("free(query)", 30, MUTED).move_to([4.6, -0.5, 0]) self.play(FadeIn(fr), run_time=0.3) key1 = obj(0.9, "TSIG key", AMB) freed = DashedVMobject(q2[0].copy().set_fill(opacity=0).set_stroke(FAINT), num_dashes=30) fl = T("freed", 30, MUTED).move_to(q2) self.play(ReplacementTransform(q1, key1), FadeOut(q2[0]), FadeOut(q2[1]), Create(freed), FadeIn(fl), run_time=0.8) self.caption("Then reuse it") leak = T("reads the key", 30, ACC, bold=True).next_to(key1, RIGHT, 0.35) st = stop().next_to(freed, RIGHT, 0.35) self.play(p1.animate.shift(RIGHT * 0.25), p2.animate.shift(RIGHT * 0.25), run_time=0.3) self.play(Indicate(key1, color=ACC), FadeIn(leak), FadeIn(st, scale=0.8), run_time=0.7) self.wait(1.4) self.clear_all() # 5. What that buys, and what it does not. self.caption("Worst case: a crash", GRN) rce = T("remote code execution", 64, ACC, bold=True).move_to([0, 0.6, 0]) self.play(FadeIn(rce)) strike = Line(rce.get_left(), rce.get_right(), color=INK, stroke_width=6) dos = T("denial of service", 64, GRN, bold=True).move_to([0, -0.9, 0]) self.play(Create(strike), run_time=0.4) self.play(FadeIn(dos, shift=UP * 0.2)) self.wait(0.8) self.caption("Not a fix for the other 31", MUTED, 46) same = T("assertion exits still exit \\textperiodcentered{} floods still flood \\textperiodcentered{}" " poisoning still poisons", 30, MUTED).move_to([0, -2.4, 0]) self.play(FadeIn(same)) self.wait(1.6) self.clear_all() # 6. It runs. self.caption("BIND 9.20.30 on Fil-C") items = [ "BIND's unit tests pass", "DNSSEC-validating resolver", "AXFR, nsupdate, rndc", "image laid out like ISC's", f"about {SLOWDOWN}× slower", ] rows = VGroup() for i, s in enumerate(items): mark = T(r"{\fontspec{DejaVu Sans}" + ("✓" if i < 4 else "–") + "}", 40, GRN if i < 4 else MUTED, bold=True) rows.add(VGroup(mark, T(s, 40, INK if i < 4 else MUTED)).arrange(RIGHT, buff=0.35)) rows.arrange(DOWN, aligned_edge=LEFT, buff=0.35).move_to([0, -0.4, 0]) self.play(LaggedStart(*[FadeIn(r, shift=RIGHT * 0.2) for r in rows], lag_ratio=0.3), run_time=2.0) self.wait(1.4) self.clear_all() # 7. Where to get it. name = T("Fil-BIND", 120, GRN, bold=True).move_to([0, 1.3, 0]) tag = T("a research build of BIND 9 in memory-safe C", 36, MUTED).next_to(name, DOWN, 0.35) pull = M("docker pull ghcr.io/mbrock/filnix-bind:9.20.30", 32, INK).move_to([0, -1.2, 0]) url = T("mbrock.github.io/filnix/fil-bind", 34, ACC, bold=True).move_to([0, -2.4, 0]) self.play(FadeIn(name, scale=0.9), run_time=0.7) self.play(FadeIn(tag)) self.play(FadeIn(pull), FadeIn(url)) self.wait(3.0)