On 12/10/19 1:45 pm, Andrew Gregory wrote:
system() runs the provided command via a shell, which is subject to command injection. Even though pacman already provides a mechanism to sign and verify the databases containing the urls, certain distributions have yet to get their act together and start signing databases, leaving them vulnerable to MITM attacks. Replacing the system call with an almost equivalent exec call removes the possibility of a shell-injection attack for those users.
Signed-off-by: Andrew Gregory
<snip>
@@ -230,17 +300,26 @@ static int download_with_xfercommand(const char *url, const char *localpath, unlink(destfile); }
- tempcmd = strdup(config->xfercommand); - /* replace all occurrences of %o with fn.part */ - if(strstr(tempcmd, "%o")) { - usepart = 1; - parsedcmd = strreplace(tempcmd, "%o", tempfile); - free(tempcmd); - tempcmd = parsedcmd; + if((argv = calloc(config->xfercommand_argc + 1, sizeof(char*))) == NULL) {
need to free this at the end.