Merge pull request #1944 from tcatm/fix-vlog

log: avoid buffer overflow in vlog
This commit is contained in:
Michael Stapelberg 2015-09-21 14:48:30 +02:00
commit ee5db875c2
1 changed files with 9 additions and 0 deletions

View File

@ -246,6 +246,15 @@ static void vlog(const bool print, const char *fmt, va_list args) {
len += vsnprintf(message + len, sizeof(message) - len, fmt, args); len += vsnprintf(message + len, sizeof(message) - len, fmt, args);
if (len >= sizeof(message)) { if (len >= sizeof(message)) {
fprintf(stderr, "BUG: single log message > 4k\n"); fprintf(stderr, "BUG: single log message > 4k\n");
/* vsnprintf returns the number of bytes that *would have been written*,
* not the actual amount written. Thus, limit len to sizeof(message) to avoid
* memory corruption and outputting garbage later. */
len = sizeof(message);
/* Punch in a newline so the next log message is not dangling at
* the end of the truncated message. */
message[len - 2] = '\n';
} }
/* If there is no space for the current message in the ringbuffer, we /* If there is no space for the current message in the ringbuffer, we