On Mon, 21 Oct 2024 13:37:53 +0100 Giovanni Cabiddu giovanni.cabiddu@intel.com wrote:
The unsigned variable `size_t len` is cast to the signed type `loff_t` when passed to the function check_add_overflow(). This function considers the type of the destination, which is of type loff_t (signed), potentially leading to an overflow. This issue is similar to the one described in the link below.
Remove the cast.
Note that even if check_add_overflow() is bypassed, by setting `len` to a value that is greater than LONG_MAX (which is considered as a negative value after the cast), the function copy_from_user(), invoked a few lines later, will not perform any copy and return `len` as (len > INT_MAX) causing qat_vf_resume_write() to fail with -EFAULT.
Fixes: bb208810b1ab ("vfio/qat: Add vfio_pci driver for Intel QAT SR-IOV VF devices") CC: stable@vger.kernel.org # 6.10+ Link: https://lore.kernel.org/all/138bd2e2-ede8-4bcc-aa7b-f3d9de167a37@moroto.moun... Reported-by: Zijie Zhao zzjas98@gmail.com Signed-off-by: Giovanni Cabiddu giovanni.cabiddu@intel.com Reviewed-by: Xin Zeng xin.zeng@intel.com
drivers/vfio/pci/qat/main.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/vfio/pci/qat/main.c b/drivers/vfio/pci/qat/main.c index e36740a282e7..1e3563fe7cab 100644 --- a/drivers/vfio/pci/qat/main.c +++ b/drivers/vfio/pci/qat/main.c @@ -305,7 +305,7 @@ static ssize_t qat_vf_resume_write(struct file *filp, const char __user *buf, offs = &filp->f_pos; if (*offs < 0 ||
check_add_overflow((loff_t)len, *offs, &end))
check_add_overflow(len, *offs, &end))if (end > mig_dev->state_size)
Applied to vfio next branch for v6.13. Thanks,
Alex