diff options
| -rw-r--r-- | src/common/compat.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/src/common/compat.c b/src/common/compat.c index 9758751122..d3bc2f5fec 100644 --- a/src/common/compat.c +++ b/src/common/compat.c @@ -558,10 +558,17 @@ tor_vasprintf(char **strp, const char *fmt, va_list args) int len, r; va_list tmp_args; va_copy(tmp_args, args); - /* vsnprintf() was properly checked but tor_vsnprintf() available so - * why not use it? */ - len = tor_vsnprintf(buf, sizeof(buf), fmt, tmp_args); + /* Use vsnprintf to retrieve needed length. tor_vsnprintf() is not an option + * here because it will simply return -1 if buf is not large enough to hold the + * complete string. + */ + len = vsnprintf(buf, sizeof(buf), fmt, tmp_args); va_end(tmp_args); + buf[sizeof(buf) - 1] = '\0'; + if (len < 0) { + *strp = NULL; + return -1; + } if (len < (int)sizeof(buf)) { *strp = tor_strdup(buf); return len; |