This reverts commit 517e1fbeb65f5eade8d14f46ac365db6c75aea9b.
usercopy: Kernel memory exposure attempt detected from SLUB object not in SLUB page?! (offset 0, size 1048)!
kernel BUG at mm/usercopy.c:99
...
usercopy_abort+0x64/0xa0 (unreliable)
__check_heap_object+0x168/0x190
__check_object_size+0x1a0/0x200
dev_ethtool+0x2494/0x2b20
dev_ioctl+0x5d0/0x770
sock_do_ioctl+0xf0/0x1d0
sock_ioctl+0x3ec/0x5a0
__se_sys_ioctl+0xf0/0x160
system_call_exception+0xfc/0x1f0
system_call_common+0xf8/0x200
When run ethtool eth0, the BUG occurred, the code shows below,
data = vzalloc(array_size(gstrings.len, ETH_GSTRING_LEN));
copy_to_user(useraddr, data, gstrings.len * ETH_GSTRING_LEN))
The data is alloced by vmalloc(), virt_addr_valid(ptr) will return true
on PowerPC64, which leads to the panic, add back the is_vmalloc_or_module()
check to fix it.
Fixes: 517e1fbeb65f (mm/usercopy: Drop extra is_vmalloc_or_module() check)
Signed-off-by: Kefeng Wang <wangkefeng.wang@xxxxxxxxxx>
---
mm/usercopy.c | 11 +++++++++++
1 file changed, 11 insertions(+)
diff --git a/mm/usercopy.c b/mm/usercopy.c
index b3de3c4eefba..cfc845403017 100644
--- a/mm/usercopy.c
+++ b/mm/usercopy.c
@@ -225,6 +225,17 @@ static inline void check_heap_object(const void *ptr, unsigned long n,
{
struct page *page;
+ /*
+ * Some architectures (PowerPC64) return true for virt_addr_valid() on
+ * vmalloced addresses. Work around this by checking for vmalloc
+ * first.
+ *
+ * We also need to check for module addresses explicitly since we
+ * may copy static data from modules to userspace
+ */
+ if (is_vmalloc_or_module_addr(ptr))
+ return;
+
if (!virt_addr_valid(ptr))
return;
--
2.26.2
