Subject: CVE-2024-47719: iommufd: Protect against overflow of ALIGN() during iova allocation

From: Greg Kroah-Hartman <[email-masked]>

Description
===========

In the Linux kernel, the following vulnerability has been resolved:

iommufd: Protect against overflow of ALIGN() during iova allocation

Userspace can supply an iova and uptr such that the target iova alignment
becomes really big and ALIGN() overflows which corrupts the selected area
range during allocation. CONFIG_IOMMUFD_TEST can detect this:

   WARNING: CPU: 1 PID: 5092 at drivers/iommu/iommufd/io_pagetable.c:268 iopt_alloc_area_pages drivers/iommu/iommufd/io_pagetable.c:268 [inline]
   WARNING: CPU: 1 PID: 5092 at drivers/iommu/iommufd/io_pagetable.c:268 iopt_map_pages+0xf95/0x1050 drivers/iommu/iommufd/io_pagetable.c:352
   Modules linked in:
   CPU: 1 PID: 5092 Comm: syz-executor294 Not tainted 6.10.0-rc5-syzkaller-00294-g3ffea9a7a6f7 #0
   Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 06/07/2024
   RIP: 0010:iopt_alloc_area_pages drivers/iommu/iommufd/io_pagetable.c:268 [inline]
   RIP: 0010:iopt_map_pages+0xf95/0x1050 drivers/iommu/iommufd/io_pagetable.c:352
   Code: fc e9 a4 f3 ff ff e8 1a 8b 4c fc 41 be e4 ff ff ff e9 8a f3 ff ff e8 0a 8b 4c fc 90 0f 0b 90 e9 37 f5 ff ff e8 fc 8a 4c fc 90 <0f> 0b 90 e9 68 f3 ff ff 48 c7 c1 ec 82 ad 8f 80 e1 07 80 c1 03 38
   RSP: 0018:ffffc90003ebf9e0 EFLAGS: 00010293
   RAX: ffffffff85499fa4 RBX: 00000000ffffffef RCX: ffff888079b49e00
   RDX: 0000000000000000 RSI: 00000000ffffffef RDI: 0000000000000000
   RBP: ffffc90003ebfc50 R08: ffffffff85499b30 R09: ffffffff85499942
   R10: 0000000000000002 R11: ffff888079b49e00 R12: ffff8880228e0010
   R13: 0000000000000000 R14: 1ffff920007d7f68 R15: ffffc90003ebfd00
   FS:  000055557d760380(0000) GS:ffff8880b9500000(0000) knlGS:0000000000000000
   CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
   CR2: 00000000005fdeb8 CR3: 000000007404a000 CR4: 00000000003506f0
   DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
   DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
   Call Trace:
    <TASK>
    iommufd_ioas_copy+0x610/0x7b0 drivers/iommu/iommufd/ioas.c:274
    iommufd_fops_ioctl+0x4d9/0x5a0 drivers/iommu/iommufd/main.c:421
    vfs_ioctl fs/ioctl.c:51 [inline]
    __do_sys_ioctl fs/ioctl.c:907 [inline]
    __se_sys_ioctl+0xfc/0x170 fs/ioctl.c:893
    do_syscall_x64 arch/x86/entry/common.c:52 [inline]
    do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
    entry_SYSCALL_64_after_hwframe+0x77/0x7f

Cap the automatic alignment to the huge page size, which is probably a
better idea overall. Huge automatic alignments can fragment and chew up
the available IOVA space without any reason.

The Linux kernel CVE team has assigned CVE-2024-47719 to this issue.

Affected and fixed versions
===========================

	Issue introduced in 6.2 with commit 51fe6141f0f6 and fixed in 6.6.54 with commit cd6dd564ae7d
	Issue introduced in 6.2 with commit 51fe6141f0f6 and fixed in 6.10.13 with commit a6e9f9fd1477
	Issue introduced in 6.2 with commit 51fe6141f0f6 and fixed in 6.11.2 with commit 72b78287ce92
	Issue introduced in 6.2 with commit 51fe6141f0f6 and fixed in 6.12-rc1 with commit 8f6887349b2f

Please see https://www.kernel.org for a full list of currently supported
kernel versions by the kernel community.

Unaffected versions might change over time as fixes are backported to
older supported kernel versions.  The official CVE entry at
	https://cve.org/CVERecord/?id=CVE-2024-47719
will be updated if fixes are backported, please check that for the most
up to date information about this issue.

Affected files
==============

The file(s) affected by this issue are:
	drivers/iommu/iommufd/io_pagetable.c

Mitigation
==========

The Linux kernel CVE team recommends that you update to the latest
stable kernel version for this, and many other bugfixes.  Individual
changes are never tested alone, but rather are part of a larger kernel
release.  Cherry-picking individual commits is not recommended or
supported by the Linux kernel community at all.  If however, updating to
the latest release is impossible, the individual changes to resolve this
issue can be found at these commits:
	https://git.kernel.org/stable/c/cd6dd564ae7d99967ef50078216929418160b30e
	https://git.kernel.org/stable/c/a6e9f9fd14772c0b23c6d1d7002d98f9d27cb1f6
	https://git.kernel.org/stable/c/72b78287ce92802e8ba678181a34b84ae844a112
	https://git.kernel.org/stable/c/8f6887349b2f829a4121c518aeb064fc922714e4