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
--- a/arch/alpha/lib/csum_partial_copy.c
+++ b/arch/alpha/lib/csum_partial_copy.c
@@ -338,6 +338,11 @@
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
--- a/arch/sparc/kernel/sys_sparc32.c
+++ b/arch/sparc/kernel/sys_sparc32.c
@@ -169,10 +169,10 @@
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 @@
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
--- a/block/compat_ioctl.c
+++ b/block/compat_ioctl.c
@@ -70,7 +70,7 @@
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
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -3394,7 +3394,7 @@
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 @@
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
--- a/net/socket.c
+++ b/net/socket.c
@@ -3072,12 +3072,12 @@
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 @@
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 @@
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;
