[FFmpeg-devel] [PATCH 2/2] libavcodec/mpeg4videodec: Convert sprite_offset to 64bit
Michael Niedermayer
michael at niedermayer.cc
Wed May 3 06:21:51 EEST 2017
This avoids intermediates from overflowing (the final values are checked)
Fixes: runtime error: signed integer overflow: -167712 + -2147352576 cannot be represented in type 'int'
Fixes: 1298/clusterfuzz-testcase-minimized-5955580877340672
Found-by: continuous fuzzing process https://github.com/google/oss-fuzz/tree/master/targets/ffmpeg
Signed-off-by: Michael Niedermayer <michael at niedermayer.cc>
---
libavcodec/mpeg4videodec.c | 102 ++++++++++++++++++++++-----------------------
1 file changed, 50 insertions(+), 52 deletions(-)
diff --git a/libavcodec/mpeg4videodec.c b/libavcodec/mpeg4videodec.c
index 791a07bbbb..39f177f8d0 100644
--- a/libavcodec/mpeg4videodec.c
+++ b/libavcodec/mpeg4videodec.c
@@ -178,6 +178,7 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
int min_ab, i, w2, h2, w3, h3;
int sprite_ref[4][2];
int virtual_ref[2][2];
+ int64_t sprite_offset[2][2];
// only true for rectangle shapes
const int vop_ref[4][2] = { { 0, 0 }, { s->width, 0 },
@@ -257,10 +258,10 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
switch (ctx->num_sprite_warping_points) {
case 0:
- s->sprite_offset[0][0] =
- s->sprite_offset[0][1] =
- s->sprite_offset[1][0] =
- s->sprite_offset[1][1] = 0;
+ sprite_offset[0][0] =
+ sprite_offset[0][1] =
+ sprite_offset[1][0] =
+ sprite_offset[1][1] = 0;
s->sprite_delta[0][0] = a;
s->sprite_delta[0][1] =
s->sprite_delta[1][0] = 0;
@@ -269,11 +270,11 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
ctx->sprite_shift[1] = 0;
break;
case 1: // GMC only
- s->sprite_offset[0][0] = sprite_ref[0][0] - a * vop_ref[0][0];
- s->sprite_offset[0][1] = sprite_ref[0][1] - a * vop_ref[0][1];
- s->sprite_offset[1][0] = ((sprite_ref[0][0] >> 1) | (sprite_ref[0][0] & 1)) -
+ sprite_offset[0][0] = sprite_ref[0][0] - a * vop_ref[0][0];
+ sprite_offset[0][1] = sprite_ref[0][1] - a * vop_ref[0][1];
+ sprite_offset[1][0] = ((sprite_ref[0][0] >> 1) | (sprite_ref[0][0] & 1)) -
a * (vop_ref[0][0] / 2);
- s->sprite_offset[1][1] = ((sprite_ref[0][1] >> 1) | (sprite_ref[0][1] & 1)) -
+ sprite_offset[1][1] = ((sprite_ref[0][1] >> 1) | (sprite_ref[0][1] & 1)) -
a * (vop_ref[0][1] / 2);
s->sprite_delta[0][0] = a;
s->sprite_delta[0][1] =
@@ -283,22 +284,22 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
ctx->sprite_shift[1] = 0;
break;
case 2:
- s->sprite_offset[0][0] = (sprite_ref[0][0] * (1 << alpha + rho)) +
+ sprite_offset[0][0] = (sprite_ref[0][0] * (1 << alpha + rho)) +
(-r * sprite_ref[0][0] + virtual_ref[0][0]) *
(-vop_ref[0][0]) +
(r * sprite_ref[0][1] - virtual_ref[0][1]) *
(-vop_ref[0][1]) + (1 << (alpha + rho - 1));
- s->sprite_offset[0][1] = (sprite_ref[0][1] * (1 << alpha + rho)) +
+ sprite_offset[0][1] = (sprite_ref[0][1] * (1 << alpha + rho)) +
(-r * sprite_ref[0][1] + virtual_ref[0][1]) *
(-vop_ref[0][0]) +
(-r * sprite_ref[0][0] + virtual_ref[0][0]) *
(-vop_ref[0][1]) + (1 << (alpha + rho - 1));
- s->sprite_offset[1][0] = ((-r * sprite_ref[0][0] + virtual_ref[0][0]) *
+ sprite_offset[1][0] = ((-r * sprite_ref[0][0] + virtual_ref[0][0]) *
(-2 * vop_ref[0][0] + 1) +
(r * sprite_ref[0][1] - virtual_ref[0][1]) *
(-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
sprite_ref[0][0] - 16 * w2 + (1 << (alpha + rho + 1)));
- s->sprite_offset[1][1] = ((-r * sprite_ref[0][1] + virtual_ref[0][1]) *
+ sprite_offset[1][1] = ((-r * sprite_ref[0][1] + virtual_ref[0][1]) *
(-2 * vop_ref[0][0] + 1) +
(-r * sprite_ref[0][0] + virtual_ref[0][0]) *
(-2 * vop_ref[0][1] + 1) + 2 * w2 * r *
@@ -315,30 +316,22 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
min_ab = FFMIN(alpha, beta);
w3 = w2 >> min_ab;
h3 = h2 >> min_ab;
- s->sprite_offset[0][0] = (sprite_ref[0][0] * (1<<(alpha + beta + rho - min_ab))) +
- (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
- h3 * (-vop_ref[0][0]) +
- (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
- w3 * (-vop_ref[0][1]) +
- (1 << (alpha + beta + rho - min_ab - 1));
- s->sprite_offset[0][1] = (sprite_ref[0][1] * (1 << (alpha + beta + rho - min_ab))) +
- (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
- h3 * (-vop_ref[0][0]) +
- (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
- w3 * (-vop_ref[0][1]) +
- (1 << (alpha + beta + rho - min_ab - 1));
- s->sprite_offset[1][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) *
- h3 * (-2 * vop_ref[0][0] + 1) +
- (-r * sprite_ref[0][0] + virtual_ref[1][0]) *
- w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
- r * sprite_ref[0][0] - 16 * w2 * h3 +
- (1 << (alpha + beta + rho - min_ab + 1));
- s->sprite_offset[1][1] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) *
- h3 * (-2 * vop_ref[0][0] + 1) +
- (-r * sprite_ref[0][1] + virtual_ref[1][1]) *
- w3 * (-2 * vop_ref[0][1] + 1) + 2 * w2 * h3 *
- r * sprite_ref[0][1] - 16 * w2 * h3 +
- (1 << (alpha + beta + rho - min_ab + 1));
+ sprite_offset[0][0] = ((int64_t)sprite_ref[0][0] * (1 << (alpha + beta + rho - min_ab))) +
+ ((int64_t)-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3 * (-vop_ref[0][0]) +
+ ((int64_t)-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3 * (-vop_ref[0][1]) +
+ ((int64_t)1 << (alpha + beta + rho - min_ab - 1));
+ sprite_offset[0][1] = ((int64_t)sprite_ref[0][1] * (1 << (alpha + beta + rho - min_ab))) +
+ ((int64_t)-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3 * (-vop_ref[0][0]) +
+ ((int64_t)-r * sprite_ref[0][1] + virtual_ref[1][1]) * w3 * (-vop_ref[0][1]) +
+ ((int64_t)1 << (alpha + beta + rho - min_ab - 1));
+ sprite_offset[1][0] = ((int64_t)-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3 * (-2 * vop_ref[0][0] + 1) +
+ ((int64_t)-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3 * (-2 * vop_ref[0][1] + 1) +
+ (int64_t)2 * w2 * h3 * r * sprite_ref[0][0] - 16 * w2 * h3 +
+ ((int64_t)1 << (alpha + beta + rho - min_ab + 1));
+ sprite_offset[1][1] = ((int64_t)-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3 * (-2 * vop_ref[0][0] + 1) +
+ ((int64_t)-r * sprite_ref[0][1] + virtual_ref[1][1]) * w3 * (-2 * vop_ref[0][1] + 1) +
+ (int64_t)2 * w2 * h3 * r * sprite_ref[0][1] - 16 * w2 * h3 +
+ ((int64_t)1 << (alpha + beta + rho - min_ab + 1));
s->sprite_delta[0][0] = (-r * sprite_ref[0][0] + virtual_ref[0][0]) * h3;
s->sprite_delta[0][1] = (-r * sprite_ref[0][0] + virtual_ref[1][0]) * w3;
s->sprite_delta[1][0] = (-r * sprite_ref[0][1] + virtual_ref[0][1]) * h3;
@@ -353,10 +346,10 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
s->sprite_delta[0][1] == 0 &&
s->sprite_delta[1][0] == 0 &&
s->sprite_delta[1][1] == a << ctx->sprite_shift[0]) {
- s->sprite_offset[0][0] >>= ctx->sprite_shift[0];
- s->sprite_offset[0][1] >>= ctx->sprite_shift[0];
- s->sprite_offset[1][0] >>= ctx->sprite_shift[1];
- s->sprite_offset[1][1] >>= ctx->sprite_shift[1];
+ sprite_offset[0][0] >>= ctx->sprite_shift[0];
+ sprite_offset[0][1] >>= ctx->sprite_shift[0];
+ sprite_offset[1][0] >>= ctx->sprite_shift[1];
+ sprite_offset[1][1] >>= ctx->sprite_shift[1];
s->sprite_delta[0][0] = a;
s->sprite_delta[0][1] = 0;
s->sprite_delta[1][0] = 0;
@@ -369,18 +362,18 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
int shift_c = 16 - ctx->sprite_shift[1];
if (shift_c < 0 || shift_y < 0 ||
- FFABS(s->sprite_offset[0][0]) >= INT_MAX >> shift_y ||
- FFABS(s->sprite_offset[1][0]) >= INT_MAX >> shift_c ||
- FFABS(s->sprite_offset[0][1]) >= INT_MAX >> shift_y ||
- FFABS(s->sprite_offset[1][1]) >= INT_MAX >> shift_c
+ FFABS(sprite_offset[0][0]) >= INT_MAX >> shift_y ||
+ FFABS(sprite_offset[1][0]) >= INT_MAX >> shift_c ||
+ FFABS(sprite_offset[0][1]) >= INT_MAX >> shift_y ||
+ FFABS(sprite_offset[1][1]) >= INT_MAX >> shift_c
) {
avpriv_request_sample(s->avctx, "Too large sprite shift or offset");
goto overflow;
}
for (i = 0; i < 2; i++) {
- s->sprite_offset[0][i] *= 1 << shift_y;
- s->sprite_offset[1][i] *= 1 << shift_c;
+ sprite_offset[0][i] *= 1 << shift_y;
+ sprite_offset[1][i] *= 1 << shift_c;
s->sprite_delta[0][i] *= 1 << shift_y;
s->sprite_delta[1][i] *= 1 << shift_y;
ctx->sprite_shift[i] = 16;
@@ -392,16 +385,16 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
s->sprite_delta[i][1] - a * (1LL<<16)
};
- if (llabs(s->sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL)) >= INT_MAX ||
- llabs(s->sprite_offset[0][i] + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX ||
- llabs(s->sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL) + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX ||
+ if (llabs(sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL)) >= INT_MAX ||
+ llabs(sprite_offset[0][i] + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX ||
+ llabs(sprite_offset[0][i] + s->sprite_delta[i][0] * (w+16LL) + s->sprite_delta[i][1] * (h+16LL)) >= INT_MAX ||
llabs(s->sprite_delta[i][0] * (w+16LL)) >= INT_MAX ||
llabs(s->sprite_delta[i][1] * (w+16LL)) >= INT_MAX ||
llabs(sd[0]) >= INT_MAX ||
llabs(sd[1]) >= INT_MAX ||
- llabs(s->sprite_offset[0][i] + sd[0] * (w+16LL)) >= INT_MAX ||
- llabs(s->sprite_offset[0][i] + sd[1] * (h+16LL)) >= INT_MAX ||
- llabs(s->sprite_offset[0][i] + sd[0] * (w+16LL) + sd[1] * (h+16LL)) >= INT_MAX
+ llabs(sprite_offset[0][i] + sd[0] * (w+16LL)) >= INT_MAX ||
+ llabs(sprite_offset[0][i] + sd[1] * (h+16LL)) >= INT_MAX ||
+ llabs(sprite_offset[0][i] + sd[0] * (w+16LL) + sd[1] * (h+16LL)) >= INT_MAX
) {
avpriv_request_sample(s->avctx, "Overflow on sprite points");
goto overflow;
@@ -410,6 +403,11 @@ static int mpeg4_decode_sprite_trajectory(Mpeg4DecContext *ctx, GetBitContext *g
s->real_sprite_warping_points = ctx->num_sprite_warping_points;
}
+ s->sprite_offset[0][0] = sprite_offset[0][0];
+ s->sprite_offset[0][1] = sprite_offset[0][1];
+ s->sprite_offset[1][0] = sprite_offset[1][0];
+ s->sprite_offset[1][1] = sprite_offset[1][1];
+
return 0;
overflow:
memset(s->sprite_offset, 0, sizeof(s->sprite_offset));
--
2.11.0
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