Commit 90fc00a6 authored by Clément Bœsch's avatar Clément Bœsch

avformat/subtitles: add a next line jumper and use it.

This fixes a bunch of possible overread in avformat with the idiom p +=
strcspn(p, "\n") + 1 (strcspn() can focus on the trailing '\0' if no
'\n' is found, so the +1 leads to an overread).

Note on lavf/matroskaenc: no extra subtitles.o Makefile dependency is
added because only the header is required for ff_subtitles_next_line().

Note on lavf/mpsubdec: code gets slightly complex to avoid an infinite
loop in the probing since there is no more forced increment.
parent cfcd55db
......@@ -63,7 +63,7 @@ static int jacosub_probe(AVProbeData *p)
return AVPROBE_SCORE_EXTENSION + 1;
return 0;
}
ptr += strcspn(ptr, "\n") + 1;
ptr += ff_subtitles_next_line(ptr);
}
return 0;
}
......
......@@ -28,6 +28,7 @@
#include "isom.h"
#include "matroska.h"
#include "riff.h"
#include "subtitles.h"
#include "wv.h"
#include "libavutil/avstring.h"
......@@ -1363,7 +1364,7 @@ static int srt_get_duration(uint8_t **buf)
s_hsec += 1000*s_sec; e_hsec += 1000*e_sec;
duration = e_hsec - s_hsec;
}
*buf += strcspn(*buf, "\n") + 1;
*buf += ff_subtitles_next_line(*buf);
}
return duration;
}
......
......@@ -47,7 +47,7 @@ static int microdvd_probe(AVProbeData *p)
sscanf(ptr, "{%*d}{%*d}%c", &c) != 1 &&
sscanf(ptr, "{DEFAULT}{}%c", &c) != 1)
return 0;
ptr += strcspn(ptr, "\n") + 1;
ptr += ff_subtitles_next_line(ptr);
}
return AVPROBE_SCORE_MAX;
}
......
......@@ -43,7 +43,7 @@ static int mpl2_probe(AVProbeData *p)
if (sscanf(ptr, "[%"SCNd64"][%"SCNd64"]%c", &start, &end, &c) != 3 &&
sscanf(ptr, "[%"SCNd64"][]%c", &start, &c) != 2)
return 0;
ptr += strcspn(ptr, "\n") + 1;
ptr += ff_subtitles_next_line(ptr);
if (ptr >= ptr_end)
return 0;
}
......
......@@ -37,11 +37,16 @@ static int mpsub_probe(AVProbeData *p)
const char *ptr_end = p->buf + p->buf_size;
while (ptr < ptr_end) {
int inc;
if (!memcmp(ptr, "FORMAT=TIME", 11))
return AVPROBE_SCORE_EXTENSION;
if (!memcmp(ptr, "FORMAT=", 7))
return AVPROBE_SCORE_EXTENSION / 3;
ptr += strcspn(ptr, "\n") + 1;
inc = ff_subtitles_next_line(ptr);
if (!inc)
break;
ptr += inc;
}
return 0;
}
......
......@@ -44,7 +44,7 @@ static int srt_probe(AVProbeData *p)
&& sscanf(ptr, "%*d:%*2d:%*2d%*1[,.]%*3d --> %*d:%*2d:%*2d%*1[,.]%3d", &v) == 1)
return AVPROBE_SCORE_MAX;
num = atoi(ptr);
ptr += strcspn(ptr, "\n") + 1;
ptr += ff_subtitles_next_line(ptr);
}
return 0;
}
......@@ -65,12 +65,10 @@ static int64_t get_pts(const char **buf, int *duration,
int64_t start = (hh1*3600LL + mm1*60LL + ss1) * 1000LL + ms1;
int64_t end = (hh2*3600LL + mm2*60LL + ss2) * 1000LL + ms2;
*duration = end - start;
*buf += strcspn(*buf, "\n");
*buf += !!**buf;
*buf += ff_subtitles_next_line(*buf);
return start;
}
*buf += strcspn(*buf, "\n");
*buf += !!**buf;
*buf += ff_subtitles_next_line(*buf);
}
return AV_NOPTS_VALUE;
}
......
......@@ -96,4 +96,14 @@ const char *ff_smil_get_attr_ptr(const char *s, const char *attr);
*/
void ff_subtitles_read_chunk(AVIOContext *pb, AVBPrint *buf);
/**
* Get the number of characters to increment to jump to the next line, or to
* the end of the string.
*/
static av_always_inline int ff_subtitles_next_line(const char *ptr)
{
int n = strcspn(ptr, "\n");
return n + !!*ptr;
}
#endif /* AVFORMAT_SUBTITLES_H */
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