From: Jason Gunthorpe jgg@nvidia.com
[ Upstream commit fd8c1a4aee973e87d890a5861e106625a33b2c4e ]
syzkaller hits a WARN_ON when trying to have a uptr close to UINTPTR_MAX:
WARNING: CPU: 1 PID: 393 at drivers/iommu/iommufd/selftest.c:403 iommufd_test+0xb19/0x16f0 Modules linked in: CPU: 1 PID: 393 Comm: repro Not tainted 6.2.0-c9c3395d5e3d #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/2014 RIP: 0010:iommufd_test+0xb19/0x16f0 Code: 94 c4 31 ff 44 89 e6 e8 a5 54 17 ff 45 84 e4 0f 85 bb 0b 00 00 41 be fb ff ff ff e8 31 53 17 ff e9 a0 f7 ff ff e8 27 53 17 ff <0f> 0b 41 be 8 RSP: 0018:ffffc90000eabdc0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffffffff8214c487 RDX: 0000000000000000 RSI: ffff88800f5c8000 RDI: 0000000000000002 RBP: ffffc90000eabe48 R08: 0000000000000000 R09: 0000000000000001 R10: 0000000000000001 R11: 0000000000000000 R12: 00000000cd2b0000 R13: 00000000cd2af000 R14: 0000000000000000 R15: ffffc90000eabe68 FS: 00007f94d76d5740(0000) GS:ffff88807dd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000020000043 CR3: 0000000006880006 CR4: 0000000000770ee0 PKRU: 55555554 Call Trace: <TASK> ? write_comp_data+0x2f/0x90 iommufd_fops_ioctl+0x1ef/0x310 __x64_sys_ioctl+0x10e/0x160 ? __pfx_iommufd_fops_ioctl+0x10/0x10 do_syscall_64+0x3b/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc
Check that the user memory range doesn't overflow.
Fixes: f4b20bb34c83 ("iommufd: Add kernel support for testing iommufd") Link: https://lore.kernel.org/r/0-v1-95390ed1df8d+8f-iommufd_mock_overflow_jgg@nvi... Reviewed-by: Kevin Tian kevin.tian@intel.com Reported-by: Pengfei Xu pengfei.xu@intel.com Link: https://lore.kernel.org/r/Y/hOiilV1wJvu/Hv@xpf.sh.intel.com Signed-off-by: Jason Gunthorpe jgg@nvidia.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/iommu/iommufd/selftest.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-)
diff --git a/drivers/iommu/iommufd/selftest.c b/drivers/iommu/iommufd/selftest.c index cfb5fe9a5e0ee..76c46847dc494 100644 --- a/drivers/iommu/iommufd/selftest.c +++ b/drivers/iommu/iommufd/selftest.c @@ -339,10 +339,12 @@ static int iommufd_test_md_check_pa(struct iommufd_ucmd *ucmd, { struct iommufd_hw_pagetable *hwpt; struct mock_iommu_domain *mock; + uintptr_t end; int rc;
if (iova % MOCK_IO_PAGE_SIZE || length % MOCK_IO_PAGE_SIZE || - (uintptr_t)uptr % MOCK_IO_PAGE_SIZE) + (uintptr_t)uptr % MOCK_IO_PAGE_SIZE || + check_add_overflow((uintptr_t)uptr, (uintptr_t)length, &end)) return -EINVAL;
hwpt = get_md_pagetable(ucmd, mockpt_id, &mock); @@ -390,7 +392,10 @@ static int iommufd_test_md_check_refs(struct iommufd_ucmd *ucmd, void __user *uptr, size_t length, unsigned int refs) { - if (length % PAGE_SIZE || (uintptr_t)uptr % PAGE_SIZE) + uintptr_t end; + + if (length % PAGE_SIZE || (uintptr_t)uptr % PAGE_SIZE || + check_add_overflow((uintptr_t)uptr, (uintptr_t)length, &end)) return -EINVAL;
for (; length; length -= PAGE_SIZE) {