In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
iommu\/iommufd: Fix NULL pointer deref in iommufd_ioas_change_process when racing with iopt_map_file_pages<\/p>\n
iommufd_ioas_change_process() iterates every IOAS area while only
\nholding every IOAS iova_rwsem, so it assumes every area has a non-NULL
\npages pointer. That assumption can be false when it runs concurrently
\nwith iopt_map_file_pages().<\/p>\n
iopt_map_pages() executes in two phases. It first creates the area and
\ninserts it into the interval tree under iova_rwsem, with area->pages
\nstill NULL. It then drops iova_rwsem and later fills area->pages
\nunder domains_rwsem. This leaves a window between area creation and
\narea->pages fill where a concurrent iommufd_ioas_change_process()
\ncan observe the area and dereference a NULL area->pages pointer,
\nleading to a NULL pointer dereference:<\/p>\n
BUG: kernel NULL pointer dereference, address: 00000000000000c0
\n#PF: supervisor read access in kernel mode
\n#PF: error_code(0x0000) – not-present page
\nPGD 4b655067 P4D 4b655067 PUD 0
\nOops: Oops: 0000 [#1] SMP NOPTI
\nCPU: 0 UID: 0 PID: 11841 Comm: syz.1.628 Not tainted 7.1.0 #3 PREEMPT(full)
\nHardware name: QEMU Ubuntu 24.04 PC v2 (i440FX + PIIX, arch_caps fix, 1996), BIOS 1.16.3-debian-1.16.3-2 04\/01\/2014
\nRIP: 0010:iommufd_ioas_change_process+0x419\/0xd50 drivers\/iommu\/iommufd\/ioas.c:538
\nCode: 48 89 c3 48 85 c0 0f 84 cc 00 00 00 e8 10 f5 cb fd 48 8d 7b 68 e8 a7 b5 eb fd 48 8b 6b 68 48 8d bd c0 00 00 00 e8 17 b2 eb fd ad c0 00 00 00 bf 01 00 00 00 89 ee e8 85 ef cb fd 83 fd 01 74
\nRSP: 0018:ffffc90015c17d28 EFLAGS: 00010246
\nRAX: ffff8880186d5328 RBX: ffff88801d25e240 RCX: 0000000080000000
\nRDX: 00000000000002d7 RSI: ffffffff83ba9e10 RDI: 00000000000000c0
\nRBP: 0000000000000000 R08: ffffffff8e781eb8 R09: 0000000000000000
\nR10: 00000000000000c0 R11: ffffffff83ba9e29 R12: ffff88802e216008
\nR13: ffff88802e216000 R14: 0000000000000001 R15: 0000000000000000
\nFS: 00007f4aea3f66c0(0000) GS:ffff8880b1fa1000(0000) knlGS:0000000000000000
\nCS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
\nCR2: 00000000000000c0 CR3: 000000004b75c000 CR4: 0000000000350ef0
\nCall Trace:<\/p>\n
iommufd_fops_ioctl+0x287\/0x400 drivers\/iommu\/iommufd\/main.c:533
\n vfs_ioctl fs\/ioctl.c:51 [inline]
\n __do_sys_ioctl fs\/ioctl.c:597 [inline]
\n __se_sys_ioctl fs\/ioctl.c:583 [inline]
\n __x64_sys_ioctl+0x120\/0x170 fs\/ioctl.c:583
\n x64_sys_call+0x1092\/0x1fb0 arch\/x86\/include\/generated\/asm\/syscalls_64.h:17
\n do_syscall_x64 arch\/x86\/entry\/syscall_64.c:63 [inline]
\n do_syscall_64+0x10a\/0x680 arch\/x86\/entry\/syscall_64.c:94
\n entry_SYSCALL_64_after_hwframe+0x77\/0x7f
\nRIP: 0033:0x7f4aec1a82bd
\nCode: ff c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 3d 01 f0 ff ff 73 01 c3 48 c7 c1 b0 ff ff ff f7 d8 64 89 01 48
\nRSP: 002b:00007f4aea3f6018 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
\nRAX: ffffffffffffffda RBX: 00007f4aec436090 RCX: 00007f4aec1a82bd
\nRDX: 0000200000000180 RSI: 0000000000003b92 RDI: 0000000000000003
\nRBP: 00007f4aec250295 R08: 0000000000000000 R09: 0000000000000000
\nR10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
\nR13: 00007f4aec436128 R14: 00007f4aec436090 R15: 00007ffd04ef23e0<\/p>\n
Modules linked in:
\nCR2: 00000000000000c0
\n—[ end trace 0000000000000000 ]—
\nRIP: 0010:iommufd_ioas_change_process+0x419\/0xd50 drivers\/iommu\/iommufd\/ioas.c:538
\nCode: 48 89 c3 48 85 c0 0f 84 cc 00 00 00 e8 10 f5 cb fd 48 8d 7b 68 e8 a7 b5 eb fd 48 8b 6b 68 48 8d bd c0 00 00 00 e8 17 b2 eb fd ad c0 00 00 00 bf 01 00 00 00 89 ee e8 85 ef cb fd 83 fd 01 74
\nRSP: 0018:ffffc90015c17d28 EFLAGS: 00010246
\nRAX: ffff8880186d5328 RBX: ffff88801d25e240 RCX: 0000000080000000
\nRDX: 00000000000002d7 RSI: ffffffff83ba9e10 RDI: 00000000000000c0
\nRBP: 0000000000000000 R08: ffffffff8e781eb8 R09: 0000000000000000
\nR10: 00000000000000c0 R11: ffffffff83ba9e29 R12: ffff88802e216008
\nR13: ffff88802e216000 R14: 0000000000000001 R15: 0000000000000000
\nFS: 00007f4aea3f66c0(000
\n—truncated—<\/p>\n","protected":false},"excerpt":{"rendered":"
In the Linux kernel, the following vulnerability has been resolved:<\/p>\n
iommu\/iommufd: Fix NULL pointer deref in iommufd_ioas_change_process when racing with iopt_map_file_pages<\/p>\n
iommufd_ioas_change_proc<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-17321","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/17321","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=17321"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17321"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17321"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}