Re: [patch 058/209] audit: rework execve audit
On Fri, Jul 27, 2007 at 04:13:10PM -0400, Steve Grubb wrote:
> + len = strnlen_user(p, MAX_ARG_PAGES*PAGE_SIZE);
> + /*
> + * We just created this mm, if we can't find the strings
> + * we just copied into it something is _very_ wrong. Similar
> + * for strings that are too long, we should not have created
> + * any.
> + */
> + if (!len || len > MAX_ARG_STRLEN) {
> + WARN_ON(1);
> + send_sig(SIGKILL, current, 0);
> + }
Which is right here ^^^
Any ideas?
Empty string in the middle of argv? Quite legal...
; cat foo.c
#include <stdio.h>
main(int argc, char **argv)
{
while (argc--) {
printf("<%d:%s>", strlen(*argv), *argv);
argv++;
}
printf("\n");
return 0;
}
; gcc foo.c
; ./a.out a b
<7:./a.out><1:a><1:b>
; ./a.out a "" b
<7:./a.out><1:a><0:><1:b>
;
IOW, it's trivial to arrange - len can be 0 just fine...