KASAN: slab-out-of-bounds Read in copy_from_sockptr

Status: upstream: reported syz repro on 2026/08/04 14:54
Subsystems: net
Labels: prio:high
[Documentation on labels]
Reported-by: syzbot+6c98d6eb7aabb6b1ad39@syzkaller.appspotmail.com
Fix commit: d0c80dbb9704 net/atm: fix slab-out-of-bounds read in vcc_setsockopt()
Patched on: [ci-upstream-kasan-badwrites-root ci-upstream-kasan-gce-root ci-upstream-kasan-gce-selinux-root ci-upstream-net-kasan-gce ci-upstream-net-this-kasan-gce ci2-upstream-fs ci2-upstream-kcsan-gce], missing on: [ci-qemu-gce-upstream-auto ci-qemu-native-arm64-kvm ci-qemu-upstream ci-qemu-upstream-386 ci-qemu2-arm32 ci-qemu2-arm64 ci-qemu2-arm64-compat ci-qemu2-arm64-mte ci-qemu2-riscv64 ci-snapshot-upstream-root ci-upstream-bpf-kasan-gce ci-upstream-bpf-next-kasan-gce ci-upstream-gce-arm64 ci-upstream-gce-leak ci-upstream-kasan-gce ci-upstream-kasan-gce-386 ci-upstream-kasan-gce-smack-root ci-upstream-kmsan-gce-386-root ci-upstream-kmsan-gce-root ci-upstream-linux-next-kasan-gce-root ci-upstream-rust-kasan-gce ci2-upstream-usb]
First crash: 4d09h, last: 2h39m
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision
79a13e4a assessment-security DenialOfService: ✅ Exploitable: ✅ FilesystemTrigger: ❌ NetworkTrigger: ❌ PeripheralTrigger: ❌ RemoteTrigger: ❌ Unprivileged: ✅ UserNamespace: ✅ VMGuestTrigger: ❌ VMHostTrigger: ❌ KASAN: slab-out-of-bounds Read in copy_from_sockptr 2026/08/04 00:00 2026/08/04 00:00 2026/08/04 00:36 cb1adeae
Discussions (3)
Title Replies (including bot) Last reply
[PATCH v2 net] net/atm: fix slab-out-of-bounds read in vcc_setsockopt() 2 (2) 2026/08/06 16:50
[PATCH net] net/atm: fix slab-out-of-bounds read in vcc_setsockopt() 2 (2) 2026/08/05 06:44
[syzbot] [net?] KASAN: slab-out-of-bounds Read in copy_from_sockptr 0 (2) 2026/08/05 05:39
Similar bugs (1)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-6.1 KASAN: slab-out-of-bounds Read in copy_from_sockptr 17 syz 3 3d22h 4d03h 0/3 upstream: reported syz repro on 2026/08/03 04:18

Sample crash report:
==================================================================
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr_offset include/linux/sockptr.h:49 [inline]
BUG: KASAN: slab-out-of-bounds in copy_from_sockptr+0x44/0x1b8 include/linux/sockptr.h:61
Read of size 84 at addr ffff0000ce07d780 by task syz.0.17/4923

CPU: 0 UID: 0 PID: 4923 Comm: syz.0.17 Not tainted syzkaller #0 PREEMPT 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/02/2026
Call trace:
 show_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:499 (C)
 __dump_stack+0x30/0x40 lib/dump_stack.c:94
 dump_stack_lvl+0xd8/0x12c lib/dump_stack.c:120
 print_address_description+0xb0/0x238 mm/kasan/report.c:378
 print_report+0x68/0x84 mm/kasan/report.c:482
 kasan_report+0x8c/0xc4 mm/kasan/report.c:595
 check_region_inline mm/kasan/generic.c:-1 [inline]
 kasan_check_range+0x17c/0x1ac mm/kasan/generic.c:200
 __asan_memcpy+0x3c/0x84 mm/kasan/shadow.c:105
 copy_from_sockptr_offset include/linux/sockptr.h:49 [inline]
 copy_from_sockptr+0x44/0x1b8 include/linux/sockptr.h:61
 vcc_setsockopt+0x174/0x450 net/atm/common.c:725
 pvc_setsockopt+0x84/0xb0 net/atm/pvc.c:72
 do_sock_setsockopt+0x1f0/0x330 net/socket.c:2368
 __sys_setsockopt+0x104/0x170 net/socket.c:2393
 __do_sys_setsockopt net/socket.c:2399 [inline]
 __se_sys_setsockopt net/socket.c:2396 [inline]
 __arm64_sys_setsockopt+0xc8/0xe4 net/socket.c:2396
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:738
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:757
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590

Allocated by task 4923:
 kasan_save_stack mm/kasan/common.c:57 [inline]
 kasan_save_track+0x40/0x78 mm/kasan/common.c:78
 kasan_save_alloc_info+0x44/0x54 mm/kasan/generic.c:570
 poison_kmalloc_redzone mm/kasan/common.c:398 [inline]
 __kasan_kmalloc+0x9c/0xb4 mm/kasan/common.c:415
 kasan_kmalloc include/linux/kasan.h:263 [inline]
 __do_kmalloc_node mm/slub.c:5334 [inline]
 __kmalloc_noprof+0x340/0x6b8 mm/slub.c:5359
 _kmalloc_noprof include/linux/slab.h:992 [inline]
 _kzalloc_noprof include/linux/slab.h:1309 [inline]
 sockopt_alloc_buf kernel/bpf/cgroup.c:2010 [inline]
 __cgroup_bpf_run_filter_setsockopt+0x1f4/0xbbc kernel/bpf/cgroup.c:2051
 do_sock_setsockopt+0x2e8/0x330 net/socket.c:2350
 __sys_setsockopt+0x104/0x170 net/socket.c:2393
 __do_sys_setsockopt net/socket.c:2399 [inline]
 __se_sys_setsockopt net/socket.c:2396 [inline]
 __arm64_sys_setsockopt+0xc8/0xe4 net/socket.c:2396
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x244 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xec/0x23c arch/arm64/kernel/syscall.c:121
 do_el0_svc+0x4c/0x5c arch/arm64/kernel/syscall.c:140
 el0_svc+0x64/0x260 arch/arm64/kernel/entry-common.c:738
 el0t_64_sync_handler+0x48/0x148 arch/arm64/kernel/entry-common.c:757
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:590

The buggy address belongs to the object at ffff0000ce07d780
 which belongs to the cache kmalloc-64 of size 64
The buggy address is located 0 bytes inside of
 allocated 53-byte region [ffff0000ce07d780, ffff0000ce07d7b5)

The buggy address belongs to the physical page:
page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x10e07d
flags: 0x5ffc00000000000(node=0|zone=2|lastcpupid=0x7ff)
page_type: f5(slab)
raw: 05ffc00000000000 ffff0000c00018c0 dead000000000100 dead000000000122
raw: 0000000000000000 0000000800200020 00000000f5000000 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff0000ce07d680: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff0000ce07d700: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff0000ce07d780: 00 00 00 00 00 00 05 fc fc fc fc fc fc fc fc fc
                                     ^
 ffff0000ce07d800: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
 ffff0000ce07d880: fa fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
==================================================================

Crashes (16):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/08/07 00:16 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci db788396cbb1 c38879ea .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/05 12:59 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 b3eac40e .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/05 05:38 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 d4abbeac .config console log report syz / log [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/07 04:53 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci db788396cbb1 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/06 21:41 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci db788396cbb1 c38879ea .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/06 04:57 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 cd5b1963 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/05 11:07 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 b3eac40e .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/05 06:27 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/05 04:57 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/04 19:51 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/04 14:16 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/04 00:56 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 a68cb31b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/03 19:59 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 a68cb31b .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/03 04:07 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/02 22:21 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
2026/08/02 22:18 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 7235a3e71949 e611ffe1 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 KASAN: slab-out-of-bounds Read in copy_from_sockptr
* Struck through repros no longer work on HEAD.