[FFmpeg-devel] [PATCH] libavformat/vorbiscomment.c:rm warning ‘%03d’ directive output may be truncated (PR #20366)

[FFmpeg-devel] [PATCH] libavformat/vorbiscomment.c:rm warning ‘%03d’ directive output may be truncated (PR #20366)

[caifan via ffmpeg-devel]

PR #20366 opened by caifan
URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20366
Patch URL: https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/20366.patch

warning: ‘%03d’ directive output may be truncated writing between 3 and 10 bytes into a region of size 4 [-Wformat-truncation=]
warning: ‘%02d’ directive output may be truncated writing between 2 and 3 bytes into a region of size between 1 and 7 [-Wformat-truncation=]

Signed-off-by: caifan3 <caifan3@xiaomi.com>


From 08b5aaad4c7ff709c0691c78675a3de681347193 Mon Sep 17 00:00:00 2001
From: caifan3 <caifan3@xiaomi.com>
Date: Fri, 29 Aug 2025 16:21:40 +0800
Subject: [PATCH] =?UTF-8?q?libavformat/vorbiscomment.c:rm=20warning=20?=
 =?UTF-8?q?=E2=80=98%03d=E2=80=99=20directive=20output=20may=20be=20trunca?=
 =?UTF-8?q?ted?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

warning: ‘%03d’ directive output may be truncated writing between 3 and 10 bytes into a region of size 4 [-Wformat-truncation=]
warning: ‘%02d’ directive output may be truncated writing between 2 and 3 bytes into a region of size between 1 and 7 [-Wformat-truncation=]

Signed-off-by: caifan3 <caifan3@xiaomi.com>
---
 libavformat/vorbiscomment.c | 14 +++++++++++---
 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/libavformat/vorbiscomment.c b/libavformat/vorbiscomment.c
index abe12fd586..1fc2066785 100644
--- a/libavformat/vorbiscomment.c
+++ b/libavformat/vorbiscomment.c
@@ -93,15 +93,23 @@ int ff_vorbiscomment_write(AVIOContext *pb, const AVDictionary *m,
             AVChapter *chp = chapters[i];
             char chapter_time[13];
             char chapter_number[4];
-            int h, m, s, ms;
+            int h, m, s, ms, ret;
 
             s  = av_rescale(chp->start, chp->time_base.num, chp->time_base.den);
             h  = s / 3600;
             m  = (s / 60) % 60;
             ms = av_rescale_q(chp->start, chp->time_base, av_make_q(   1, 1000)) % 1000;
             s  = s % 60;
-            snprintf(chapter_number, sizeof(chapter_number), "%03d", i);
-            snprintf(chapter_time, sizeof(chapter_time), "%02d:%02d:%02d.%03d", h, m, s, ms);
+            ret = snprintf(chapter_number, sizeof(chapter_number), "%03d", i);
+            if (ret < 0 || ret >= sizeof(chapter_number)) {
+                av_log(NULL, AV_LOG_ERROR, "Chapter number %d too large to format\n", i);
+                return AVERROR(EINVAL);
+            }
+            ret = snprintf(chapter_time, sizeof(chapter_time), "%02d:%02d:%02d.%03d", h, m, s, ms);
+            if (ret < 0 || ret >= sizeof(chapter_time)) {
+                av_log(NULL, AV_LOG_ERROR, "Chapter time %02d:%02d:%02d.%03d too large to format\n", h, m, s, ms);
+                return AVERROR(EINVAL);
+            }
             avio_wl32(pb, 10 + 1 + 12);
             avio_write(pb, "CHAPTER", 7);
             avio_write(pb, chapter_number, 3);
-- 
2.49.1

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