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Code Issues Releases Activity

dxv: Check to make sure we don't overrun buffers on corrupt inputs

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Signed-off-by: Martin Storsjö <martin@martin.st>
This commit is contained in:
Martin Storsjö 2016-07-28 13:45:24 +03:00
parent e328178da9
commit 7ebdffc353
1 changed files with 11 additions and 3 deletions
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14
libavcodec/dxv.c
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@ -125,7 +125,7 @@ static int dxv_decompress_dxt1(AVCodecContext *avctx)
AV_WL32(ctx->tex_data + 4, bytestream2_get_le32(gbc)); AV_WL32(ctx->tex_data + 4, bytestream2_get_le32(gbc));
/* Process input until the whole texture has been filled */ /* Process input until the whole texture has been filled */
while (pos < ctx->tex_size / 4) { while (pos + 2 <= ctx->tex_size / 4) {
CHECKPOINT(2); CHECKPOINT(2);
/* Copy two elements from a previous offset or from the input buffer */ /* Copy two elements from a previous offset or from the input buffer */
@ -178,7 +178,7 @@ static int dxv_decompress_dxt5(AVCodecContext *avctx)
AV_WL32(ctx->tex_data + 12, bytestream2_get_le32(gbc)); AV_WL32(ctx->tex_data + 12, bytestream2_get_le32(gbc));
/* Process input until the whole texture has been filled */ /* Process input until the whole texture has been filled */
while (pos < ctx->tex_size / 4) { while (pos + 2 <= ctx->tex_size / 4) {
if (run) { if (run) {
run--; run--;
@ -207,7 +207,7 @@ static int dxv_decompress_dxt5(AVCodecContext *avctx)
check += probe; check += probe;
} while (probe == 0xFFFF); } while (probe == 0xFFFF);
} }
while (check && pos < ctx->tex_size / 4) { while (check && pos + 4 <= ctx->tex_size / 4) {
prev = AV_RL32(ctx->tex_data + 4 * (pos - 4)); prev = AV_RL32(ctx->tex_data + 4 * (pos - 4));
AV_WL32(ctx->tex_data + 4 * pos, prev); AV_WL32(ctx->tex_data + 4 * pos, prev);
pos++; pos++;
@ -252,6 +252,8 @@ static int dxv_decompress_dxt5(AVCodecContext *avctx)
case 2: case 2:
/* Copy two dwords from a previous index */ /* Copy two dwords from a previous index */
idx = 8 + bytestream2_get_le16(gbc); idx = 8 + bytestream2_get_le16(gbc);
if (idx > pos || (unsigned int)(pos - idx) + 2 > ctx->tex_size / 4)
return AVERROR_INVALIDDATA;
prev = AV_RL32(ctx->tex_data + 4 * (pos - idx)); prev = AV_RL32(ctx->tex_data + 4 * (pos - idx));
AV_WL32(ctx->tex_data + 4 * pos, prev); AV_WL32(ctx->tex_data + 4 * pos, prev);
pos++; pos++;
@ -274,9 +276,13 @@ static int dxv_decompress_dxt5(AVCodecContext *avctx)
} }
CHECKPOINT(4); CHECKPOINT(4);
if (pos + 2 > ctx->tex_size / 4)
return AVERROR_INVALIDDATA;
/* Copy two elements from a previous offset or from the input buffer */ /* Copy two elements from a previous offset or from the input buffer */
if (op) { if (op) {
if (idx > pos || (unsigned int)(pos - idx) + 2 > ctx->tex_size / 4)
return AVERROR_INVALIDDATA;
prev = AV_RL32(ctx->tex_data + 4 * (pos - idx)); prev = AV_RL32(ctx->tex_data + 4 * (pos - idx));
AV_WL32(ctx->tex_data + 4 * pos, prev); AV_WL32(ctx->tex_data + 4 * pos, prev);
pos++; pos++;
@ -287,6 +293,8 @@ static int dxv_decompress_dxt5(AVCodecContext *avctx)
} else { } else {
CHECKPOINT(4); CHECKPOINT(4);
if (op && (idx > pos || (unsigned int)(pos - idx) + 2 > ctx->tex_size / 4))
return AVERROR_INVALIDDATA;
if (op) if (op)
prev = AV_RL32(ctx->tex_data + 4 * (pos - idx)); prev = AV_RL32(ctx->tex_data + 4 * (pos - idx));
else else