[OVERFLOW] in arch/mips/au1000/common/power.c

[OVERFLOW] in arch/mips/au1000/common/power.c

[Stefan Esser]

Hi,

sorry for the possible double posting, but my other mail seems
to be lost...

The following code seems very fishy ;)

static int pm_do_freq(ctl_table * ctl, int write, struct file *file,
                      void *buffer, size_t * len)
{
        int retval = 0, i;
        unsigned long val, pll;
#define TMPBUFLEN 64
#define MAX_CPU_FREQ 396
        char buf[8], *p;

	...

        spin_lock_irqsave(&pm_lock, flags);
        if (!write) {
                *len = 0;
        } else {
                /* Parse the new frequency */
                if (*len > TMPBUFLEN - 1) {
                        spin_unlock_irqrestore(&pm_lock, flags);
                        return -EFAULT;
                }
                if (copy_from_user(buf, buffer, *len)) {
                        spin_unlock_irqrestore(&pm_lock, flags);
                        return -EFAULT;
                }
                buf[*len] = 0;
                p = buf;

Earth to linux kernel. Earth to linux kernel. Your buffer is only 8
bytes big and not TMPBUFLEN - 1

Looks like a 56 byte stackoverflow to me ;)

Stefan Esser

-- 

--------------------------------------------------------------------------
 Stefan Esser                                        s.esser@e-matters.de
 e-matters Security                         http://security.e-matters.de/

 GPG-Key                gpg --keyserver pgp.mit.edu --recv-key 0xCF6CAE69 
 Key fingerprint       B418 B290 ACC0 C8E5 8292  8B72 D6B0 7704 CF6C AE69
--------------------------------------------------------------------------
 Did I help you? Consider a gift:            http://wishlist.suspekt.org/
--------------------------------------------------------------------------