[ Upstream commit e1be43d9b5d0d1310dbd90185a8e5c7145dde40f ]
In order to perform more open-coded replacements of common allocation
size arithmetic, the kernel needs saturating (SIZE_MAX) helpers for
multiplication, addition, and subtraction. For example, it is common in
allocators, especially on realloc, to add to an existing size:
p = krealloc(map->patch,
sizeof(struct reg_sequence) * (map->patch_regs + num_regs),
GFP_KERNEL);
There is no existing saturating replacement for this calculation, and
just leaving the addition open coded inside array_size() could
potentially overflow as well. For example, an overflow in an expression
for a size_t argument might wrap to zero:
array_size(anything, something_at_size_max + 1) == 0
Introduce size_mul(), size_add(), and size_sub() helpers that
implicitly promote arguments to size_t and saturated calculations for
use in allocations. With these helpers it is also possible to redefine
array_size(), array3_size(), flex_array_size(), and struct_size() in
terms of the new helpers.
As with the check_*_overflow() helpers, the new helpers use __must_check,
though what is really desired is a way to make sure that assignment is
only to a size_t lvalue. Without this, it's still possible to introduce
overflow/underflow via type conversion (i.e. from size_t to int).
Enforcing this will currently need to be left to static analysis or
future use of -Wconversion.
Additionally update the overflow unit tests to force runtime evaluation
for the pathological cases.
Cc: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Cc: Nathan Chancellor <nathan@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Nick Desaulniers <ndesaulniers@google.com>
Cc: Leon Romanovsky <leon@kernel.org>
Cc: Keith Busch <kbusch@kernel.org>
Cc: Len Baker <len.baker@gmx.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Stable-dep-of: d692873cbe86 ("gve: Use size_add() in call to struct_size()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
commit 3bb2a01caa813d3a1845d378bbe4169ef280d394 upstream.
In kobject_get_path(), if kobj->name is changed between calls
get_kobj_path_length() and fill_kobj_path() and the length becomes
longer, then fill_kobj_path() will have an out-of-bounds bug.
The actual current problem occurs when the ixgbe probe.
In ixgbe_mii_bus_init(), if the length of netdev->dev.kobj.name
length becomes longer, out-of-bounds will occur.
cpu0 cpu1
ixgbe_probe
register_netdev(netdev)
netdev_register_kobject
device_add
kobject_uevent // Sending ADD events
systemd-udevd // rename netdev
dev_change_name
device_rename
kobject_rename
ixgbe_mii_bus_init |
mdiobus_register |
__mdiobus_register |
device_register |
device_add |
kobject_uevent |
kobject_get_path |
len = get_kobj_path_length // old name |
path = kzalloc(len, gfp_mask); |
kobj->name = name;
/* name length becomes
* longer
*/
fill_kobj_path /* kobj path length is
* longer than path,
* resulting in out of
* bounds when filling path
*/
This is the kasan report:
==================================================================
BUG: KASAN: slab-out-of-bounds in fill_kobj_path+0x50/0xc0
Write of size 7 at addr ff1100090573d1fd by task kworker/28:1/673
Workqueue: events work_for_cpu_fn
Call Trace:
<TASK>
dump_stack_lvl+0x34/0x48
print_address_description.constprop.0+0x86/0x1e7
print_report+0x36/0x4f
kasan_report+0xad/0x130
kasan_check_range+0x35/0x1c0
memcpy+0x39/0x60
fill_kobj_path+0x50/0xc0
kobject_get_path+0x5a/0xc0
kobject_uevent_env+0x140/0x460
device_add+0x5c7/0x910
__mdiobus_register+0x14e/0x490
ixgbe_probe.cold+0x441/0x574 [ixgbe]
local_pci_probe+0x78/0xc0
work_for_cpu_fn+0x26/0x40
process_one_work+0x3b6/0x6a0
worker_thread+0x368/0x520
kthread+0x165/0x1a0
ret_from_fork+0x1f/0x30
This reproducer triggers that bug:
while:
do
rmmod ixgbe
sleep 0.5
modprobe ixgbe
sleep 0.5
When calling fill_kobj_path() to fill path, if the name length of
kobj becomes longer, return failure and retry. This fixes the problem.
Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2")
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Link: https://lore.kernel.org/r/20221220012143.52141-1-wanghai38@huawei.com
Signed-off-by: Oleksandr Tymoshenko <ovt@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
