From: Andrew Morton <akpm@linux-foundation.org>
To: akpm@linux-foundation.org, alex.bou9@gmail.com,
gustavoars@kernel.org, ira.weiny@intel.com, jhubbard@nvidia.com,
jingxiangfeng@huawei.com, jrdr.linux@gmail.com,
keescook@chromium.org, linux-mm@kvack.org, lkp@intel.com,
mm-commits@vger.kernel.org, mporter@kernel.crashing.org,
torvalds@linux-foundation.org
Subject: [patch 2/9] rapidio: avoid bogus __alloc_size warning
Date: Thu, 09 Sep 2021 20:10:22 -0700 [thread overview]
Message-ID: <20210910031022.kmBJ5voRH%akpm@linux-foundation.org> (raw)
In-Reply-To: <20210909200948.090d4e213ca34b5ad1325a7e@linux-foundation.org>
From: Kees Cook <keescook@chromium.org>
Subject: rapidio: avoid bogus __alloc_size warning
GCC 9.3 (but not later) incorrectly evaluates the arguments to
check_copy_size(), getting seemingly confused by the size being returned
from array_size(). Instead, perform the calculation once, which both
makes the code more readable and avoids the bug in GCC.
In file included from arch/x86/include/asm/preempt.h:7,
from include/linux/preempt.h:78,
from include/linux/spinlock.h:55,
from include/linux/mm_types.h:9,
from include/linux/buildid.h:5,
from include/linux/module.h:14,
from drivers/rapidio/devices/rio_mport_cdev.c:13:
In function 'check_copy_size',
inlined from 'copy_from_user' at include/linux/uaccess.h:191:6,
inlined from 'rio_mport_transfer_ioctl' at drivers/rapidio/devices/rio_mport_cdev.c:983:6:
include/linux/thread_info.h:213:4: error: call to '__bad_copy_to' declared with attribute error: copy destination size is too small
213 | __bad_copy_to();
| ^~~~~~~~~~~~~~~
But the allocation size and the copy size are identical:
transfer = vmalloc(array_size(sizeof(*transfer), transaction.count));
if (!transfer)
return -ENOMEM;
if (unlikely(copy_from_user(transfer,
(void __user *)(uintptr_t)transaction.block,
array_size(sizeof(*transfer), transaction.count)))) {
Link: https://lkml.kernel.org/r/20210909161409.2250920-1-keescook@chromium.org
Link: https://lore.kernel.org/linux-mm/202109091134.FHnRmRxu-lkp@intel.com/
Signed-off-by: Kees Cook <keescook@chromium.org>
Reported-by: kernel test robot <lkp@intel.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Alexandre Bounine <alex.bou9@gmail.com>
Cc: Jing Xiangfeng <jingxiangfeng@huawei.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Gustavo A. R. Silva <gustavoars@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
drivers/rapidio/devices/rio_mport_cdev.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
--- a/drivers/rapidio/devices/rio_mport_cdev.c~rapidio-avoid-bogus-__alloc_size-warning
+++ a/drivers/rapidio/devices/rio_mport_cdev.c
@@ -965,6 +965,7 @@ static int rio_mport_transfer_ioctl(stru
struct rio_transfer_io *transfer;
enum dma_data_direction dir;
int i, ret = 0;
+ size_t size;
if (unlikely(copy_from_user(&transaction, arg, sizeof(transaction))))
return -EFAULT;
@@ -976,13 +977,14 @@ static int rio_mport_transfer_ioctl(stru
priv->md->properties.transfer_mode) == 0)
return -ENODEV;
- transfer = vmalloc(array_size(sizeof(*transfer), transaction.count));
+ size = array_size(sizeof(*transfer), transaction.count);
+ transfer = vmalloc(size);
if (!transfer)
return -ENOMEM;
if (unlikely(copy_from_user(transfer,
(void __user *)(uintptr_t)transaction.block,
- array_size(sizeof(*transfer), transaction.count)))) {
+ size))) {
ret = -EFAULT;
goto out_free;
}
@@ -994,8 +996,7 @@ static int rio_mport_transfer_ioctl(stru
transaction.sync, dir, &transfer[i]);
if (unlikely(copy_to_user((void __user *)(uintptr_t)transaction.block,
- transfer,
- array_size(sizeof(*transfer), transaction.count))))
+ transfer, size)))
ret = -EFAULT;
out_free:
_
next prev parent reply other threads:[~2021-09-10 3:10 UTC|newest]
Thread overview: 37+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-09-10 3:09 incoming Andrew Morton
2021-09-10 3:10 ` [patch 1/9] mm: move kvmalloc-related functions to slab.h Andrew Morton
2021-09-10 3:10 ` Andrew Morton [this message]
2021-09-10 3:10 ` [patch 3/9] Compiler Attributes: add __alloc_size() for better bounds checking Andrew Morton
2021-09-10 3:10 ` [patch 4/9] checkpatch: add __alloc_size() to known $Attribute Andrew Morton
2021-09-10 3:10 ` [patch 5/9] slab: clean up function declarations Andrew Morton
2021-09-10 3:10 ` [patch 6/9] slab: add __alloc_size attributes for better bounds checking Andrew Morton
2021-09-10 3:10 ` [patch 7/9] mm/page_alloc: " Andrew Morton
2021-09-10 3:10 ` [patch 8/9] percpu: " Andrew Morton
2021-09-10 3:10 ` [patch 9/9] mm/vmalloc: " Andrew Morton
2021-09-10 17:23 ` Linus Torvalds
2021-09-10 18:43 ` Kees Cook
2021-09-10 19:17 ` Linus Torvalds
2021-09-10 19:32 ` Kees Cook
2021-09-10 19:49 ` Nick Desaulniers
2021-09-10 20:16 ` Linus Torvalds
2021-09-10 20:47 ` Kees Cook
2021-09-10 20:58 ` Nick Desaulniers
2021-09-10 21:07 ` Kees Cook
2021-09-11 5:29 ` Joe Perches
2021-09-21 23:37 ` Kees Cook
2021-09-21 23:45 ` Joe Perches
2021-09-22 2:25 ` function prototype element ordering Kees Cook
2021-09-22 4:24 ` Joe Perches
2021-09-24 19:43 ` Kees Cook
2021-09-22 7:24 ` Alexey Dobriyan
2021-09-22 8:51 ` Joe Perches
2021-09-22 10:45 ` Alexey Dobriyan
2021-09-22 11:19 ` Jani Nikula
2021-09-22 21:15 ` Linus Torvalds
2021-09-23 5:10 ` Joe Perches
2021-09-25 19:40 ` David Laight
2021-09-26 21:03 ` Linus Torvalds
2021-09-27 8:21 ` David Laight
2021-09-27 9:22 ` Willy Tarreau
2021-09-10 17:11 ` incoming Kees Cook
2021-09-10 20:13 ` incoming Kees Cook
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