6.6-stable review patch. If anyone has any objections, please let me know.
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From: Jason Gunthorpe jgg@nvidia.com
[ Upstream commit e6a973af11135439de32ece3b9cbe3bfc043bea8 ]
syzkaller found it could overflow math in the test infrastructure and cause a WARN_ON by corrupting the reserved interval tree. This only effects test kernels with CONFIG_IOMMUFD_TEST.
Validate the user input length in the test ioctl.
Fixes: f4b20bb34c83 ("iommufd: Add kernel support for testing iommufd") Link: https://patch.msgid.link/r/0-v1-cd99f6049ba5+51-iommufd_syz_add_resv_jgg@nvi... Reviewed-by: Samiullah Khawaja skhawaja@google.com Reviewed-by: Kevin Tian kevin.tian@intel.com Tested-by: Yi Liu yi.l.liu@intel.com Reported-by: syzbot+57fdb0cf6a0c5d1f15a2@syzkaller.appspotmail.com Closes: https://lore.kernel.org/all/69368129.a70a0220.38f243.008f.GAE@google.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/iommufd/selftest.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c index 00b794d74e03b..8025ff65ed4de 100644 --- a/drivers/iommu/iommufd/selftest.c +++ b/drivers/iommu/iommufd/selftest.c @@ -512,14 +512,20 @@ static int iommufd_test_add_reserved(struct iommufd_ucmd *ucmd, unsigned int mockpt_id, unsigned long start, size_t length) { + unsigned long last; struct iommufd_ioas *ioas; int rc;
+ if (!length) + return -EINVAL; + if (check_add_overflow(start, length - 1, &last)) + return -EOVERFLOW; + ioas = iommufd_get_ioas(ucmd->ictx, mockpt_id); if (IS_ERR(ioas)) return PTR_ERR(ioas); down_write(&ioas->iopt.iova_rwsem); - rc = iopt_reserve_iova(&ioas->iopt, start, start + length - 1, NULL); + rc = iopt_reserve_iova(&ioas->iopt, start, last, NULL); up_write(&ioas->iopt.iova_rwsem); iommufd_put_object(&ioas->obj); return rc;