Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com> --- Lots of fate tests fail if this assumption is not fulfilled. libavcodec/rl2.c | 10 ++++++---- 1 file changed, 6 insertions(+), 4 deletions(-) diff --git a/libavcodec/rl2.c b/libavcodec/rl2.c index 2464ad59ac..467c4913a4 100644 --- a/libavcodec/rl2.c +++ b/libavcodec/rl2.c @@ -65,7 +65,7 @@ static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, int i; const uint8_t *back_frame = s->back_frame; const uint8_t *in_end = in + size; - const uint8_t *out_end = out + stride * s->avctx->height; + const uint8_t *out_end = out + stride * s->avctx->height - stride_adj; uint8_t *line_end; /** copy start of the background frame */ @@ -100,18 +100,20 @@ static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, *out++ = (val == 0x80) ? *back_frame : val; back_frame++; if (out == line_end) { + if (out == out_end) + return; out += stride_adj; line_end += stride; - if (len >= out_end - out) - return; } } } /** copy the rest from the background frame */ if (s->back_frame) { - while (out < out_end) { + while (1) { memcpy(out, back_frame, line_end - out); + if (line_end == out_end) + break; back_frame += line_end - out; out = line_end + stride_adj; line_end += stride; -- 2.34.1

Don't increment back_frame if it does not correspond to a real buffer. To do this, handle copying from the back frame separately from the "use coded value" codepath; also use memcpy for the former, as the chunks here are typically worth it. Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com> --- libavcodec/rl2.c | 35 ++++++++++++++++++++++++++++------- 1 file changed, 28 insertions(+), 7 deletions(-) diff --git a/libavcodec/rl2.c b/libavcodec/rl2.c index 76982f0426..7938ef1d92 100644 --- a/libavcodec/rl2.c +++ b/libavcodec/rl2.c @@ -69,13 +69,16 @@ static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, uint8_t *line_end; /** copy start of the background frame */ + if (s->back_frame) { for (i = 0; i <= base_y; i++) { - if (s->back_frame) memcpy(out, back_frame, s->avctx->width); out += stride; back_frame += s->avctx->width; } back_frame += base_x - s->avctx->width; + } else { + out += stride * (base_y + 1); + } line_end = out - stride_adj; out += base_x - stride; @@ -89,16 +92,32 @@ static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, len = *in++; if (!len) break; + val &= 0x7F; } - if (s->back_frame) + if (back_frame) { + if (!val) { + do { + size_t copy = FFMIN(line_end - out, len); + memcpy(out, back_frame, copy); + out += copy; + back_frame += copy; + len -= copy; + if (out == line_end) { + if (out == out_end) + return; + out += stride_adj; + line_end += stride; + } + } while (len > 0); + continue; + } + back_frame += len; val |= 0x80; - else - val &= ~0x80; + } while (len--) { - *out++ = (val == 0x80) ? *back_frame : val; - back_frame++; + *out++ = val; if (out == line_end) { if (out == out_end) return; @@ -164,7 +183,9 @@ static av_cold int rl2_decode_init(AVCodecContext *avctx) back_size = avctx->extradata_size - EXTRADATA1_SIZE; if (back_size > 0) { - uint8_t *back_frame = av_mallocz(avctx->width*avctx->height); + /* The 254 are padding to ensure that pointer arithmetic stays within + * the buffer. */ + uint8_t *back_frame = av_mallocz(avctx->width * avctx->height + 254); if (!back_frame) return AVERROR(ENOMEM); rl2_rle_decode(s, avctx->extradata + EXTRADATA1_SIZE, back_size, -- 2.34.1

Andreas Rheinhardt:

This check is intended to be avoid buffer overflows, yet there are four problems with it: 1. It has an in-built off-by-one error: len == out_end - out is perfectly fine and nothing to worry about. This off-by-one error led to the pixel in the lower-right corner not being set properly for the back frame of the sample from the rl2 FATE-test. This pixel is copied to every frame which is the reason for the update to the reference file of said test. With this patch, the output of the decoder matches the output as captured from the reference decoder* (apart from the fact that said reference somehow lacks the top part of the frame (copied over from the background frame)). 2. Given that the stride of the buffer may be different from the width of the video (despite one pixel taking one byte), there is a second check lateron making the first check redundant (if one returns immediately; a simple break at the second check is not sufficient, because it only exits the inner loop). 3. The check is based around the assumption of the stride being positive (it has this in common with the other check which will be fixed in a future commit). 4. Even after fixing the off-by-one error, the check in question is still triggered by all the non-background frames in the FATE sample as well as by A1100100.RL2. In all these cases, they use len == 255 and val == 128. For videos with background frame this just means "copy from the background frame", which would be done anyway lateron.* Yet for videos without it copying it is necessary to avoid leaving uninitialized parts in the video.

*: Available in https://samples.mplayerhq.hu/game-formats/voyeur-rl2/ **: Due to this, the code that copies the rest from the back frame is no longer executed for any of the samples available on the sample server. Given that these are only the files from the demo version of this game, I don't know whether this code is executed for any file in existence or not.

Signed-off-by: Andreas Rheinhardt <andreas.rheinhardt@outlook.com> --- libavcodec/rl2.c | 5 +- tests/ref/fate/rl2 | 216 ++++++++++++++++++++++----------------------- 2 files changed, 109 insertions(+), 112 deletions(-)

diff --git a/libavcodec/rl2.c b/libavcodec/rl2.c index 5dedb96266..2464ad59ac 100644 --- a/libavcodec/rl2.c +++ b/libavcodec/rl2.c @@ -91,9 +91,6 @@ static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, break; }

- if (len >= out_end - out) - break; - if (s->back_frame) val |= 0x80; else @@ -106,7 +103,7 @@ static void rl2_rle_decode(Rl2Context *s, const uint8_t *in, int size, out += stride_adj; line_end += stride; if (len >= out_end - out) - break; + return; } } } diff --git a/tests/ref/fate/rl2 b/tests/ref/fate/rl2 index 9189822503..a3c6a75d05 100644 --- a/tests/ref/fate/rl2 +++ b/tests/ref/fate/rl2 @@ -3,111 +3,111 @@ #codec_id 0: rawvideo #dimensions 0: 320x200 #sar 0: 0/1 -0, 0, 0, 1, 192000, 0x7112a667 -0, 1, 1, 1, 192000, 0x6936abf3 -0, 2, 2, 1, 192000, 0xb1f08981 -0, 3, 3, 1, 192000, 0x4ce7fece -0, 4, 4, 1, 192000, 0xf04decde -0, 5, 5, 1, 192000, 0x47fef74b -0, 6, 6, 1, 192000, 0x99b42ac2 -0, 7, 7, 1, 192000, 0x3c4c419d -0, 8, 8, 1, 192000, 0x66bf5588 -0, 9, 9, 1, 192000, 0xe1de4725 -0, 10, 10, 1, 192000, 0x348b2af9 -0, 11, 11, 1, 192000, 0x1ce73e83 -0, 12, 12, 1, 192000, 0xcdaa6e02 -0, 13, 13, 1, 192000, 0x370dc2ce -0, 14, 14, 1, 192000, 0x1e1e40fe -0, 15, 15, 1, 192000, 0x491470a4 -0, 16, 16, 1, 192000, 0x88c43e9a -0, 17, 17, 1, 192000, 0x036f3f44 -0, 18, 18, 1, 192000, 0xc8be7e25 -0, 19, 19, 1, 192000, 0xbedb397d -0, 20, 20, 1, 192000, 0x97c410f4 -0, 21, 21, 1, 192000, 0xc2c8225d -0, 22, 22, 1, 192000, 0xe396bccb -0, 23, 23, 1, 192000, 0x7e89c24c -0, 24, 24, 1, 192000, 0xb044954c -0, 25, 25, 1, 192000, 0x335890dd -0, 26, 26, 1, 192000, 0x58a457c0 -0, 27, 27, 1, 192000, 0xeb0f4798 -0, 28, 28, 1, 192000, 0x0bfc39a1 -0, 29, 29, 1, 192000, 0x06a6905a -0, 30, 30, 1, 192000, 0x5300c99b -0, 31, 31, 1, 192000, 0x38f3f845 -0, 32, 32, 1, 192000, 0x6afa3543 -0, 33, 33, 1, 192000, 0x5106a8e0 -0, 34, 34, 1, 192000, 0xc76f0dab -0, 35, 35, 1, 192000, 0x8efa6939 -0, 36, 36, 1, 192000, 0x64ea23d7 -0, 37, 37, 1, 192000, 0x421a2817 -0, 38, 38, 1, 192000, 0xc854fa18 -0, 39, 39, 1, 192000, 0x4a10d59c -0, 40, 40, 1, 192000, 0x72637829 -0, 41, 41, 1, 192000, 0xdbbe2796 -0, 42, 42, 1, 192000, 0xff742e6b -0, 43, 43, 1, 192000, 0xf94b9346 -0, 44, 44, 1, 192000, 0xc90ea53c -0, 45, 45, 1, 192000, 0x177483bb -0, 46, 46, 1, 192000, 0x3510369c -0, 47, 47, 1, 192000, 0x501034bf -0, 48, 48, 1, 192000, 0x315c744b -0, 49, 49, 1, 192000, 0xdb5048ae -0, 50, 50, 1, 192000, 0x09a86221 -0, 51, 51, 1, 192000, 0xb9c9568a -0, 52, 52, 1, 192000, 0x5eee665b -0, 53, 53, 1, 192000, 0xdef85517 -0, 54, 54, 1, 192000, 0x7896b5ad -0, 55, 55, 1, 192000, 0x19fbad39 -0, 56, 56, 1, 192000, 0x63358748 -0, 57, 57, 1, 192000, 0xca0196a3 -0, 58, 58, 1, 192000, 0x0b321da3 -0, 59, 59, 1, 192000, 0xa07af07e -0, 60, 60, 1, 192000, 0x21f9310c -0, 61, 61, 1, 192000, 0x62d59874 -0, 62, 62, 1, 192000, 0x021227b4 -0, 63, 63, 1, 192000, 0x01dac0c2 -0, 64, 64, 1, 192000, 0xf3c33a74 -0, 65, 65, 1, 192000, 0xeebe83b7 -0, 66, 66, 1, 192000, 0x9ec77f97 -0, 67, 67, 1, 192000, 0xc91c2e37 -0, 68, 68, 1, 192000, 0x7b58751d -0, 69, 69, 1, 192000, 0xb178dfbb -0, 70, 70, 1, 192000, 0x2a63b5be -0, 71, 71, 1, 192000, 0x44a407ac -0, 72, 72, 1, 192000, 0x9a8e17dd -0, 73, 73, 1, 192000, 0x5546f4c8 -0, 74, 74, 1, 192000, 0xeda94586 -0, 75, 75, 1, 192000, 0x941dfa6b -0, 76, 76, 1, 192000, 0x9772301d -0, 77, 77, 1, 192000, 0x8be16b16 -0, 78, 78, 1, 192000, 0x26dd4496 -0, 79, 79, 1, 192000, 0x27823797 -0, 80, 80, 1, 192000, 0xacc914f7 -0, 81, 81, 1, 192000, 0xcbb72c9b -0, 82, 82, 1, 192000, 0x4bd3391c -0, 83, 83, 1, 192000, 0x4e6adbfe -0, 84, 84, 1, 192000, 0x7a791c75 -0, 85, 85, 1, 192000, 0xc4f59c94 -0, 86, 86, 1, 192000, 0xc4f59c94 -0, 87, 87, 1, 192000, 0x984a4a0b -0, 88, 88, 1, 192000, 0x3353f31f -0, 89, 89, 1, 192000, 0xa9d4dc5a -0, 90, 90, 1, 192000, 0xb33425d0 -0, 91, 91, 1, 192000, 0x546d768a -0, 92, 92, 1, 192000, 0xfefbe5c9 -0, 93, 93, 1, 192000, 0xbd6be61d -0, 94, 94, 1, 192000, 0xf5792731 -0, 95, 95, 1, 192000, 0xccde0582 -0, 96, 96, 1, 192000, 0x857d58ee -0, 97, 97, 1, 192000, 0xe914ce48 -0, 98, 98, 1, 192000, 0x1f736298 -0, 99, 99, 1, 192000, 0xec0b4846 -0, 100, 100, 1, 192000, 0xe1422624 -0, 101, 101, 1, 192000, 0x56e2b0e0 -0, 102, 102, 1, 192000, 0xc4190640 -0, 103, 103, 1, 192000, 0x7c461977 -0, 104, 104, 1, 192000, 0x34b1d5e8 -0, 105, 105, 1, 192000, 0xbdc70f7a -0, 106, 106, 1, 192000, 0xb466cd8d -0, 107, 107, 1, 192000, 0x0e86a04c +0, 0, 0, 1, 192000, 0x7324a772 +0, 1, 1, 1, 192000, 0x6b48acfe +0, 2, 2, 1, 192000, 0xb4028a8c +0, 3, 3, 1, 192000, 0x4ef9ffd9 +0, 4, 4, 1, 192000, 0xf25fede9 +0, 5, 5, 1, 192000, 0x4a10f856 +0, 6, 6, 1, 192000, 0x9bc62bcd +0, 7, 7, 1, 192000, 0x3e5e42a8 +0, 8, 8, 1, 192000, 0x68d15693 +0, 9, 9, 1, 192000, 0xe3f04830 +0, 10, 10, 1, 192000, 0x369d2c04 +0, 11, 11, 1, 192000, 0x1ef93f8e +0, 12, 12, 1, 192000, 0xcfbc6f0d +0, 13, 13, 1, 192000, 0x391fc3d9 +0, 14, 14, 1, 192000, 0x20304209 +0, 15, 15, 1, 192000, 0x4b2671af +0, 16, 16, 1, 192000, 0x8ad63fa5 +0, 17, 17, 1, 192000, 0x0581404f +0, 18, 18, 1, 192000, 0xcad07f30 +0, 19, 19, 1, 192000, 0xc0ed3a88 +0, 20, 20, 1, 192000, 0x99d611ff +0, 21, 21, 1, 192000, 0xc4da2368 +0, 22, 22, 1, 192000, 0xe5a8bdd6 +0, 23, 23, 1, 192000, 0x809bc357 +0, 24, 24, 1, 192000, 0xb2569657 +0, 25, 25, 1, 192000, 0x356a91e8 +0, 26, 26, 1, 192000, 0x5ab658cb +0, 27, 27, 1, 192000, 0xed2148a3 +0, 28, 28, 1, 192000, 0x0e0e3aac +0, 29, 29, 1, 192000, 0x08b89165 +0, 30, 30, 1, 192000, 0x5512caa6 +0, 31, 31, 1, 192000, 0x3b05f950 +0, 32, 32, 1, 192000, 0x6d0c364e +0, 33, 33, 1, 192000, 0x5318a9eb +0, 34, 34, 1, 192000, 0xc9810eb6 +0, 35, 35, 1, 192000, 0x910c6a44 +0, 36, 36, 1, 192000, 0x66fc24e2 +0, 37, 37, 1, 192000, 0x442c2922 +0, 38, 38, 1, 192000, 0xca66fb23 +0, 39, 39, 1, 192000, 0x4c22d6a7 +0, 40, 40, 1, 192000, 0x74757934 +0, 41, 41, 1, 192000, 0xddd028a1 +0, 42, 42, 1, 192000, 0x01952f76 +0, 43, 43, 1, 192000, 0xfb5d9451 +0, 44, 44, 1, 192000, 0xcb20a647 +0, 45, 45, 1, 192000, 0x198684c6 +0, 46, 46, 1, 192000, 0x372237a7 +0, 47, 47, 1, 192000, 0x522235ca +0, 48, 48, 1, 192000, 0x336e7556 +0, 49, 49, 1, 192000, 0xdd6249b9 +0, 50, 50, 1, 192000, 0x0bba632c +0, 51, 51, 1, 192000, 0xbbdb5795 +0, 52, 52, 1, 192000, 0x61006766 +0, 53, 53, 1, 192000, 0xe10a5622 +0, 54, 54, 1, 192000, 0x7aa8b6b8 +0, 55, 55, 1, 192000, 0x1c0dae44 +0, 56, 56, 1, 192000, 0x65478853 +0, 57, 57, 1, 192000, 0xcc1397ae +0, 58, 58, 1, 192000, 0x0d441eae +0, 59, 59, 1, 192000, 0xa28cf189 +0, 60, 60, 1, 192000, 0x240b3217 +0, 61, 61, 1, 192000, 0x64e7997f +0, 62, 62, 1, 192000, 0x042428bf +0, 63, 63, 1, 192000, 0x03ecc1cd +0, 64, 64, 1, 192000, 0xf5d53b7f +0, 65, 65, 1, 192000, 0xf0d084c2 +0, 66, 66, 1, 192000, 0xa0d980a2 +0, 67, 67, 1, 192000, 0xcb2e2f42 +0, 68, 68, 1, 192000, 0x7d6a7628 +0, 69, 69, 1, 192000, 0xb38ae0c6 +0, 70, 70, 1, 192000, 0x2c75b6c9 +0, 71, 71, 1, 192000, 0x46b608b7 +0, 72, 72, 1, 192000, 0x9ca018e8 +0, 73, 73, 1, 192000, 0x5758f5d3 +0, 74, 74, 1, 192000, 0xefbb4691 +0, 75, 75, 1, 192000, 0x962ffb76 +0, 76, 76, 1, 192000, 0x99843128 +0, 77, 77, 1, 192000, 0x8df36c21 +0, 78, 78, 1, 192000, 0x28ef45a1 +0, 79, 79, 1, 192000, 0x299438a2 +0, 80, 80, 1, 192000, 0xaedb1602 +0, 81, 81, 1, 192000, 0xcdc92da6 +0, 82, 82, 1, 192000, 0x4de53a27 +0, 83, 83, 1, 192000, 0x507cdd09 +0, 84, 84, 1, 192000, 0x7c8b1d80 +0, 85, 85, 1, 192000, 0xc7079d9f +0, 86, 86, 1, 192000, 0xc7079d9f +0, 87, 87, 1, 192000, 0x9a5c4b16 +0, 88, 88, 1, 192000, 0x3565f42a +0, 89, 89, 1, 192000, 0xabe6dd65 +0, 90, 90, 1, 192000, 0xb54626db +0, 91, 91, 1, 192000, 0x567f7795 +0, 92, 92, 1, 192000, 0x011ce6d4 +0, 93, 93, 1, 192000, 0xbf7de728 +0, 94, 94, 1, 192000, 0xf78b283c +0, 95, 95, 1, 192000, 0xcef0068d +0, 96, 96, 1, 192000, 0x878f59f9 +0, 97, 97, 1, 192000, 0xeb26cf53 +0, 98, 98, 1, 192000, 0x218563a3 +0, 99, 99, 1, 192000, 0xee1d4951 +0, 100, 100, 1, 192000, 0xe354272f +0, 101, 101, 1, 192000, 0x58f4b1eb +0, 102, 102, 1, 192000, 0xc62b074b +0, 103, 103, 1, 192000, 0x7e581a82 +0, 104, 104, 1, 192000, 0x36c3d6f3 +0, 105, 105, 1, 192000, 0xbfd91085 +0, 106, 106, 1, 192000, 0xb678ce98 +0, 107, 107, 1, 192000, 0x1098a157

Will apply this patchset tonight unless there are objections. - Andreas