From efdc96ace59d676e76434499a399d1d7df7fa093 Mon Sep 17 00:00:00 2001 From: Aaron Boushley Date: Fri, 26 Jul 2019 15:49:36 -0700 Subject: [PATCH] libavfilter/drawtext: avoid undefined behavior with GET_UTF8 Currently the GET_UTF8 usage in drawtext use a continue to skip invalid characters in a string. The macro definition states that using a loop control statement results in undefined behavior since the macro itself uses a loop. This switches drawtext to use a goto statement similar to other usages of GET_UTF8 in other parts of ffmpeg. Signed-off-by: Aaron Boushley --- libavfilter/vf_drawtext.c | 17 ++++++++++++++--- 1 file changed, 14 insertions(+), 3 deletions(-) diff --git a/libavfilter/vf_drawtext.c b/libavfilter/vf_drawtext.c index 8f4badbdb5..fd2ba84d12 100644 --- a/libavfilter/vf_drawtext.c +++ b/libavfilter/vf_drawtext.c @@ -1223,7 +1223,7 @@ static int draw_glyphs(DrawTextContext *s, AVFrame *frame, for (i = 0, p = text; *p; i++) { FT_Bitmap bitmap; Glyph dummy = { 0 }; - GET_UTF8(code, *p++, continue;); + GET_UTF8(code, *p++, goto invalid_drawing;); /* skip new line chars, just go to new line */ if (code == '\n' || code == '\r' || code == '\t') @@ -1248,6 +1248,9 @@ static int draw_glyphs(DrawTextContext *s, AVFrame *frame, bitmap.width, bitmap.rows, bitmap.pixel_mode == FT_PIXEL_MODE_MONO ? 0 : 3, 0, x1, y1); + continue; +invalid_drawing: + av_log(s, AV_LOG_DEBUG, "Invalid UTF8 character while drawing glyphs\n"); } return 0; @@ -1361,7 +1364,7 @@ static int draw_text(AVFilterContext *ctx, AVFrame *frame, /* load and cache glyphs */ for (i = 0, p = text; *p; i++) { - GET_UTF8(code, *p++, continue;); + GET_UTF8(code, *p++, goto invalid_caching;); /* get glyph */ dummy.code = code; @@ -1377,6 +1380,10 @@ static int draw_text(AVFilterContext *ctx, AVFrame *frame, y_max = FFMAX(glyph->bbox.yMax, y_max); x_min = FFMIN(glyph->bbox.xMin, x_min); x_max = FFMAX(glyph->bbox.xMax, x_max); + + continue; +invalid_caching: + av_log(ctx, AV_LOG_DEBUG, "Invalid UTF8 character while caching glyphs\n"); } s->max_glyph_h = y_max - y_min; s->max_glyph_w = x_max - x_min; @@ -1384,7 +1391,7 @@ static int draw_text(AVFilterContext *ctx, AVFrame *frame, /* compute and save position for each glyph */ glyph = NULL; for (i = 0, p = text; *p; i++) { - GET_UTF8(code, *p++, continue;); + GET_UTF8(code, *p++, goto invalid_positioning;); /* skip the \n in the sequence \r\n */ if (prev_code == '\r' && code == '\n') @@ -1417,6 +1424,10 @@ static int draw_text(AVFilterContext *ctx, AVFrame *frame, s->positions[i].y = y - glyph->bitmap_top + y_max; if (code == '\t') x = (x / s->tabsize + 1)*s->tabsize; else x += glyph->advance; + + continue; +invalid_positioning: + av_log(ctx, AV_LOG_DEBUG, "Invalid UTF8 character while positioning glyphs\n"); } max_text_line_w = FFMAX(x, max_text_line_w); -- 2.20.1 (Apple Git-117)