kernel-wide: fix missing validations on __get/__put/__copy_to/__copy_from_user()

I found the following pattern that leads in to interesting findings:

  grep -r "ret.*|=.*__put_user" *
  grep -r "ret.*|=.*__get_user" *
  grep -r "ret.*|=.*__copy" *

The __put_user() calls in compat_ioctl.c, ptrace compat, signal compat,
since those appear in compat code, we could probably expect the kernel
addresses not to be reachable in the lower 32-bit range, so I think they
might not be exploitable.

For the "__get_user" cases, I don't think those are exploitable: the worse
that can happen is that the kernel will copy kernel memory into in-kernel
buffers, and will fail immediately afterward.

The alpha csum_partial_copy_from_user() seems to be missing the
access_ok() check entirely.  The fix is inspired from x86.  This could
lead to information leak on alpha.  I also noticed that many architectures
map csum_partial_copy_from_user() to csum_partial_copy_generic(), but I
wonder if the latter is performing the access checks on every
architectures.

Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Richard Henderson <rth@twiddle.net>
Cc: Ivan Kokshaysky <ink@jurassic.park.msu.ru>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/arch/alpha/lib/csum_partial_copy.c b/arch/alpha/lib/csum_partial_copy.c
index 40736da..ffb19b7 100644 (file)
--- a/arch/alpha/lib/csum_partial_copy.c
+++ b/arch/alpha/lib/csum_partial_copy.c
@@ -338,6 +338,11 @@ csum_partial_copy_from_user(const void __user *src, void *dst, int len,
        unsigned long doff = 7 & (unsigned long) dst;
 
        if (len) {
+               if (!access_ok(VERIFY_READ, src, len)) {
+                       *errp = -EFAULT;
+                       memset(dst, 0, len);
+                       return sum;
+               }
                if (!doff) {
                        if (!soff)
                                checksum = csum_partial_cfu_aligned(

diff --git a/arch/sparc/kernel/sys_sparc32.c b/arch/sparc/kernel/sys_sparc32.c
index 3d0ddbc..7136885 100644 (file)
--- a/arch/sparc/kernel/sys_sparc32.c
+++ b/arch/sparc/kernel/sys_sparc32.c
@@ -169,10 +169,10 @@ COMPAT_SYSCALL_DEFINE5(rt_sigaction, int, sig,
                new_ka.ka_restorer = restorer;
                ret = get_user(u_handler, &act->sa_handler);
                new_ka.sa.sa_handler =  compat_ptr(u_handler);
-               ret |= __copy_from_user(&set32, &act->sa_mask, sizeof(compat_sigset_t));
+               ret |= copy_from_user(&set32, &act->sa_mask, sizeof(compat_sigset_t));
                sigset_from_compat(&new_ka.sa.sa_mask, &set32);
-               ret |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
-               ret |= __get_user(u_restorer, &act->sa_restorer);
+               ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
+               ret |= get_user(u_restorer, &act->sa_restorer);
                new_ka.sa.sa_restorer = compat_ptr(u_restorer);
                 if (ret)
                        return -EFAULT;
@@ -183,9 +183,9 @@ COMPAT_SYSCALL_DEFINE5(rt_sigaction, int, sig,
        if (!ret && oact) {
                sigset_to_compat(&set32, &old_ka.sa.sa_mask);
                ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), &oact->sa_handler);
-               ret |= __copy_to_user(&oact->sa_mask, &set32, sizeof(compat_sigset_t));
-               ret |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
-               ret |= __put_user(ptr_to_compat(old_ka.sa.sa_restorer), &oact->sa_restorer);
+               ret |= copy_to_user(&oact->sa_mask, &set32, sizeof(compat_sigset_t));
+               ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+               ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer), &oact->sa_restorer);
                if (ret)
                        ret = -EFAULT;
         }

diff --git a/block/compat_ioctl.c b/block/compat_ioctl.c
index 7e5d474..fbd5a67 100644 (file)
--- a/block/compat_ioctl.c
+++ b/block/compat_ioctl.c
@@ -70,7 +70,7 @@ static int compat_hdio_getgeo(struct gendisk *disk, struct block_device *bdev,
                return ret;
 
        ret = copy_to_user(ugeo, &geo, 4);
-       ret |= __put_user(geo.start, &ugeo->start);
+       ret |= put_user(geo.start, &ugeo->start);
        if (ret)
                ret = -EFAULT;
 

diff --git a/kernel/signal.c b/kernel/signal.c
index 50e4107..ded28b9 100644 (file)
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3394,7 +3394,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
                new_ka.sa.sa_restorer = compat_ptr(restorer);
 #endif
                ret |= copy_from_user(&mask, &act->sa_mask, sizeof(mask));
-               ret |= __get_user(new_ka.sa.sa_flags, &act->sa_flags);
+               ret |= get_user(new_ka.sa.sa_flags, &act->sa_flags);
                if (ret)
                        return -EFAULT;
                sigset_from_compat(&new_ka.sa.sa_mask, &mask);
@@ -3406,7 +3406,7 @@ COMPAT_SYSCALL_DEFINE4(rt_sigaction, int, sig,
                ret = put_user(ptr_to_compat(old_ka.sa.sa_handler), 
                               &oact->sa_handler);
                ret |= copy_to_user(&oact->sa_mask, &mask, sizeof(mask));
-               ret |= __put_user(old_ka.sa.sa_flags, &oact->sa_flags);
+               ret |= put_user(old_ka.sa.sa_flags, &oact->sa_flags);
 #ifdef __ARCH_HAS_SA_RESTORER
                ret |= put_user(ptr_to_compat(old_ka.sa.sa_restorer),
                                &oact->sa_restorer);

diff --git a/net/socket.c b/net/socket.c
index b2d7c62..0ceaa5c 100644 (file)
--- a/net/socket.c
+++ b/net/socket.c
@@ -3072,12 +3072,12 @@ static int compat_sioc_ifmap(struct net *net, unsigned int cmd,
 
        uifmap32 = &uifr32->ifr_ifru.ifru_map;
        err = copy_from_user(&ifr, uifr32, sizeof(ifr.ifr_name));
-       err |= __get_user(ifr.ifr_map.mem_start, &uifmap32->mem_start);
-       err |= __get_user(ifr.ifr_map.mem_end, &uifmap32->mem_end);
-       err |= __get_user(ifr.ifr_map.base_addr, &uifmap32->base_addr);
-       err |= __get_user(ifr.ifr_map.irq, &uifmap32->irq);
-       err |= __get_user(ifr.ifr_map.dma, &uifmap32->dma);
-       err |= __get_user(ifr.ifr_map.port, &uifmap32->port);
+       err |= get_user(ifr.ifr_map.mem_start, &uifmap32->mem_start);
+       err |= get_user(ifr.ifr_map.mem_end, &uifmap32->mem_end);
+       err |= get_user(ifr.ifr_map.base_addr, &uifmap32->base_addr);
+       err |= get_user(ifr.ifr_map.irq, &uifmap32->irq);
+       err |= get_user(ifr.ifr_map.dma, &uifmap32->dma);
+       err |= get_user(ifr.ifr_map.port, &uifmap32->port);
        if (err)
                return -EFAULT;
 
@@ -3088,12 +3088,12 @@ static int compat_sioc_ifmap(struct net *net, unsigned int cmd,
 
        if (cmd == SIOCGIFMAP && !err) {
                err = copy_to_user(uifr32, &ifr, sizeof(ifr.ifr_name));
-               err |= __put_user(ifr.ifr_map.mem_start, &uifmap32->mem_start);
-               err |= __put_user(ifr.ifr_map.mem_end, &uifmap32->mem_end);
-               err |= __put_user(ifr.ifr_map.base_addr, &uifmap32->base_addr);
-               err |= __put_user(ifr.ifr_map.irq, &uifmap32->irq);
-               err |= __put_user(ifr.ifr_map.dma, &uifmap32->dma);
-               err |= __put_user(ifr.ifr_map.port, &uifmap32->port);
+               err |= put_user(ifr.ifr_map.mem_start, &uifmap32->mem_start);
+               err |= put_user(ifr.ifr_map.mem_end, &uifmap32->mem_end);
+               err |= put_user(ifr.ifr_map.base_addr, &uifmap32->base_addr);
+               err |= put_user(ifr.ifr_map.irq, &uifmap32->irq);
+               err |= put_user(ifr.ifr_map.dma, &uifmap32->dma);
+               err |= put_user(ifr.ifr_map.port, &uifmap32->port);
                if (err)
                        err = -EFAULT;
        }
@@ -3167,25 +3167,25 @@ static int routing_ioctl(struct net *net, struct socket *sock,
                struct in6_rtmsg32 __user *ur6 = argp;
                ret = copy_from_user(&r6.rtmsg_dst, &(ur6->rtmsg_dst),
                        3 * sizeof(struct in6_addr));
-               ret |= __get_user(r6.rtmsg_type, &(ur6->rtmsg_type));
-               ret |= __get_user(r6.rtmsg_dst_len, &(ur6->rtmsg_dst_len));
-               ret |= __get_user(r6.rtmsg_src_len, &(ur6->rtmsg_src_len));
-               ret |= __get_user(r6.rtmsg_metric, &(ur6->rtmsg_metric));
-               ret |= __get_user(r6.rtmsg_info, &(ur6->rtmsg_info));
-               ret |= __get_user(r6.rtmsg_flags, &(ur6->rtmsg_flags));
-               ret |= __get_user(r6.rtmsg_ifindex, &(ur6->rtmsg_ifindex));
+               ret |= get_user(r6.rtmsg_type, &(ur6->rtmsg_type));
+               ret |= get_user(r6.rtmsg_dst_len, &(ur6->rtmsg_dst_len));
+               ret |= get_user(r6.rtmsg_src_len, &(ur6->rtmsg_src_len));
+               ret |= get_user(r6.rtmsg_metric, &(ur6->rtmsg_metric));
+               ret |= get_user(r6.rtmsg_info, &(ur6->rtmsg_info));
+               ret |= get_user(r6.rtmsg_flags, &(ur6->rtmsg_flags));
+               ret |= get_user(r6.rtmsg_ifindex, &(ur6->rtmsg_ifindex));
 
                r = (void *) &r6;
        } else { /* ipv4 */
                struct rtentry32 __user *ur4 = argp;
                ret = copy_from_user(&r4.rt_dst, &(ur4->rt_dst),
                                        3 * sizeof(struct sockaddr));
-               ret |= __get_user(r4.rt_flags, &(ur4->rt_flags));
-               ret |= __get_user(r4.rt_metric, &(ur4->rt_metric));
-               ret |= __get_user(r4.rt_mtu, &(ur4->rt_mtu));
-               ret |= __get_user(r4.rt_window, &(ur4->rt_window));
-               ret |= __get_user(r4.rt_irtt, &(ur4->rt_irtt));
-               ret |= __get_user(rtdev, &(ur4->rt_dev));
+               ret |= get_user(r4.rt_flags, &(ur4->rt_flags));
+               ret |= get_user(r4.rt_metric, &(ur4->rt_metric));
+               ret |= get_user(r4.rt_mtu, &(ur4->rt_mtu));
+               ret |= get_user(r4.rt_window, &(ur4->rt_window));
+               ret |= get_user(r4.rt_irtt, &(ur4->rt_irtt));
+               ret |= get_user(rtdev, &(ur4->rt_dev));
                if (rtdev) {
                        ret |= copy_from_user(devname, compat_ptr(rtdev), 15);
                        r4.rt_dev = (char __user __force *)devname;