Re: CPPCheck found 24 high risk bugs in Git v.1.8.3.4

From: Andreas Schwab <schwab@linux-m68k.org>
Date: Aug 20, 2013, 18:44 UTC
Message-ID: <87eh9op5gq.fsf@igel.home>
In-Reply-To: <CABPQNSZidMv4MEW+SqVm94pX4szw9QW8LFWsvBTOXYH7ezzycw@mail.gmail.com>

Erik Faye-Lund <kusmabite@gmail.com> writes:

Show 17 quoted lines

> diff --git a/compat/win32/syslog.c b/compat/win32/syslog.c
> index d015e43..0641f4e 100644
> --- a/compat/win32/syslog.c
> +++ b/compat/win32/syslog.c
> @@ -43,11 +43,14 @@ void syslog(int priority, const char *fmt, ...)
>   va_end(ap);
>
>   while ((pos = strstr(str, "%1")) != NULL) {
> - str = realloc(str, ++str_len + 1);
> - if (!str) {
> + char *tmp = realloc(str, ++str_len + 1);
> + if (!tmp) {
>   warning("realloc failed: '%s'", strerror(errno));
> + free(str);
>   return;
>   }
> + pos = tmp + (pos - str);

Pedantically, this is undefined (uses of both pos and str may trap after realloc has freed the original pointer), it is better to calculate the difference before calling realloc.

Andreas.

-- 
Andreas Schwab, schwab@linux-m68k.org
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