[FFmpeg-devel] [PATCH] ffserver: fix incorrect strlcpy usage

[Ganesh Ajjanagadde]

Somewhat ironic that this "safe" interface is actually being used
unsafely here. This fixes the usage preventing potential null pointer
dereference, where the old code was doubly broken: ctime can return
NULL, and ctime can return an arbitrarily long buffer.

Signed-off-by: Ganesh Ajjanagadde <gajjanagadde at gmail.com>
---
 ffserver.c | 9 ++++++---
 1 file changed, 6 insertions(+), 3 deletions(-)

diff --git a/ffserver.c b/ffserver.c
index 526cbfc..108523e 100644
--- a/ffserver.c
+++ b/ffserver.c
@@ -305,15 +305,18 @@ static void ffm_set_write_index(AVFormatContext *s, int64_t pos,
     ffm->file_size = file_size;
 }
 
-static char *ctime1(char *buf2, int buf_size)
+static char *ctime1(char *buf2, size_t buf_size)
 {
     time_t ti;
     char *p;
 
     ti = time(NULL);
     p = ctime(&ti);
-    av_strlcpy(buf2, p, buf_size);
-    p = buf2 + strlen(p) - 1;
+    if (!p) {
+        *buf2 = '\0';
+        return buf2;
+    }
+    p = buf2 + av_strlcpy(buf2, p, buf_size) - 1;
     if (*p == '\n')
         *p = '\0';
     return buf2;
-- 
2.6.2