Re: kern_tame.c: fix strncmp call

[Alexander Hall]

On 08/24/15 00:29, patrick keshishian wrote:

On 8/23/15, Caspar Schutijser <cas...@schutijser.com> wrote:

Patch below.

Thanks,
Caspar Schutijser


Index: sys/kern/kern_tame.c
===================================================================
RCS file: /cvs/src/sys/kern/kern_tame.c,v
retrieving revision 1.25
diff -u -p -r1.25 kern_tame.c
--- sys/kern/kern_tame.c        23 Aug 2015 19:32:20 -0000      1.25
+++ sys/kern/kern_tame.c        23 Aug 2015 21:22:38 -0000
@@ -423,7 +423,7 @@ tame_namei(struct proc *p, char *origpat
         */
        if ((p->p_p->ps_tame & _TM_TMPPATH) &&
            (p->p_tame_syscall == SYS_unlink) &&
-           strncmp(path, "/tmp/", sizeof("/tmp") - 1) == 0) {
+           strncmp(path, "/tmp/", sizeof("/tmp/") - 1) == 0) {

you are confusing sizeof() with strlen(). former counts the byte
required for the terminating NUL.

Yes, but you're missing the following "- 1", methinks...

I think the diff is correct.

/Alexander

$ cat >/tmp/a.c
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char *argv[])
{
        printf("sizeof(\"/tmp\")=%zu\n", sizeof("/tmp"));
        exit(0);
}
$ cc  /tmp/a.c -o /tmp/a
$ /tmp/a
sizeof("/tmp")=5

--patrick

                return (0);
        }