Hello,
syzbot found the following issue on:
HEAD commit: 6628e7d4c6b2 Linux 7.4-rc1 git tree: https://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git usb-testing console output: https://syzkaller.appspot.com/x/log.txt?x=1308eadd580000 kernel config: https://syzkaller.appspot.com/x/.config?x=f9bf69220d319004 dashboard link: https://syzkaller.appspot.com/bug?extid=693652ded53d3eb9cb91 compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 syz repro: https://syzkaller.appspot.com/x/repro.syz?x=17bebe69580000 C reproducer: https://syzkaller.appspot.com/x/repro.c?x=12c1344e580000
Downloadable assets: disk image: https://storage.googleapis.com/syzbot-assets/d415be35d54e/disk-6628e7d4.raw.... vmlinux: https://storage.googleapis.com/syzbot-assets/69e49385122b/vmlinux-6628e7d4.x... kernel image: https://storage.googleapis.com/syzbot-assets/51be81fff25f/bzImage-6628e7d4.x...
AI-generated root cause summary: In drivers/greybus/operation.c, gb_connection_recv() verifies that the received buffer length is at least sizeof(header) and that size >= msg_size, but fails to check whether msg_size (from header.size) is at least sizeof(header). When an incoming message has header.size < sizeof(struct gb_operation_msg_hdr), gb_operation_create_incoming() computes request_size = size - sizeof(struct gb_operation_msg_hdr), causing an unsigned size_t underflow to SIZE_MAX. While gb_operation_message_alloc() wraps the allocation size back to the short msg_size (allocating e.g. 7 bytes), gb_operation_message_init() sets payload_size to SIZE_MAX and sets payload to header + 1 (offset 8, past the end of the buffer). Consequently, request handlers like gb_svc_version_request() pass the payload_size validation and perform out-of-bounds heap reads on op->request->payload.
full analysis: https://syzkaller.appspot.com/x/ai_root_cause?x=693652ded53d3eb9cb91
IMPORTANT: if you fix the issue, please add the following tag to the commit: Reported-by: syzbot+693652ded53d3eb9cb91@syzkaller.appspotmail.com
================================================================== BUG: KASAN: slab-out-of-bounds in gb_svc_version_request drivers/greybus/svc.c:658 [inline] BUG: KASAN: slab-out-of-bounds in gb_svc_request_handler+0x10de/0x1250 drivers/greybus/svc.c:1271 Read of size 1 at addr ffff888104ad2108 by task kworker/u8:0/12
CPU: 0 UID: 0 PID: 12 Comm: kworker/u8:0 Not tainted syzkaller #0 PREEMPT(lazy) Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/07/2026 Workqueue: greybus1:0 gb_operation_work Call Trace: <TASK> __dump_stack lib/dump_stack.c:94 [inline] dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120 print_address_description mm/kasan/report.c:378 [inline] print_report+0x13d/0x4b0 mm/kasan/report.c:482 kasan_report+0xdf/0x1c0 mm/kasan/report.c:595 gb_svc_version_request drivers/greybus/svc.c:658 [inline] gb_svc_request_handler+0x10de/0x1250 drivers/greybus/svc.c:1271 gb_operation_request_handle drivers/greybus/operation.c:243 [inline] gb_operation_work+0xb7/0x990 drivers/greybus/operation.c:280 process_one_work+0xac7/0x1b10 kernel/workqueue.c:3495 process_scheduled_works kernel/workqueue.c:3578 [inline] worker_thread+0x5ef/0xe50 kernel/workqueue.c:3659 kthread+0x373/0x450 kernel/kthread.c:436 ret_from_fork+0x69f/0xc90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 </TASK>
Allocated by task 0: kasan_save_stack+0x30/0x50 mm/kasan/common.c:57 kasan_save_track+0x14/0x30 mm/kasan/common.c:78 poison_kmalloc_redzone mm/kasan/common.c:409 [inline] __kasan_kmalloc+0x8f/0xa0 mm/kasan/common.c:426 kasan_kmalloc include/linux/kasan.h:263 [inline] __do_kmalloc_node mm/slub.c:5531 [inline] __kmalloc_noprof+0x315/0x7e0 mm/slub.c:5556 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] gb_operation_message_alloc+0x9b/0x2c0 drivers/greybus/operation.c:380 gb_operation_create_common+0x9f/0x710 drivers/greybus/operation.c:532 gb_operation_create_incoming drivers/greybus/operation.c:644 [inline] gb_connection_recv_request drivers/greybus/operation.c:926 [inline] gb_connection_recv+0x1dc/0x1050 drivers/greybus/operation.c:1063 greybus_data_rcvd+0x244/0x600 drivers/greybus/connection.c:89 cport_in_callback+0x1fb/0x280 drivers/greybus/es2.c:840 __usb_hcd_giveback_urb+0x38e/0x610 drivers/usb/core/hcd.c:1657 usb_hcd_giveback_urb+0x3ca/0x4a0 drivers/usb/core/hcd.c:1741 dummy_timer+0xdb5/0x3840 drivers/usb/gadget/udc/dummy_hcd.c:2051 __run_hrtimer kernel/time/hrtimer.c:2079 [inline] __hrtimer_run_queues+0x448/0x9a0 kernel/time/hrtimer.c:2136 hrtimer_run_softirq+0x1ca/0x360 kernel/time/hrtimer.c:2153 handle_softirqs+0x209/0xa00 kernel/softirq.c:669 __do_softirq kernel/softirq.c:703 [inline] invoke_softirq kernel/softirq.c:542 [inline] __irq_exit_rcu+0x17a/0x220 kernel/softirq.c:786 irq_exit_rcu+0x9/0x30 kernel/softirq.c:809 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062 [inline] sysvec_apic_timer_interrupt+0x8f/0xb0 arch/x86/kernel/apic/apic.c:1062 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:674
The buggy address belongs to the object at ffff888104ad2100 which belongs to the cache kmalloc-8 of size 8 The buggy address is located 1 bytes to the right of allocated 7-byte region [ffff888104ad2100, ffff888104ad2107)
The buggy address belongs to the physical page: page: refcount:0 mapcount:0 mapping:0000000000000000 index:0xffff888104ad2600 pfn:0x104ad2 flags: 0x200000000000200(workingset|node=0|zone=2) page_type: f5(slab) raw: 0200000000000200 ffff888100041500 ffffea00040eb410 ffffea000403ef50 raw: ffff888104ad2600 000000000080007a 00000000f5000000 0000000000000000 page dumped because: kasan: bad access detected page_owner tracks the page as allocated page last allocated via order 0, migratetype Unmovable, gfp_mask 0xd2cc0(GFP_KERNEL|__GFP_NOWARN|__GFP_NORETRY|__GFP_COMP|__GFP_NOMEMALLOC), pid 1, tgid 1 (swapper/0), ts 5446373684 set_page_owner include/linux/page_owner.h:33 [inline] post_alloc_hook+0xfd/0x120 mm/page_alloc.c:1856 prep_new_page mm/page_alloc.c:1864 [inline] get_page_from_freelist+0xf4b/0x3440 mm/page_alloc.c:3935 __alloc_frozen_pages_noprof+0x299/0x2d50 mm/page_alloc.c:5444 alloc_slab_page mm/slub.c:3384 [inline] allocate_slab mm/slub.c:3499 [inline] new_slab+0xb1/0x6d0 mm/slub.c:3550 refill_objects+0xe3/0x410 mm/slub.c:7539 refill_sheaf mm/slub.c:2917 [inline] __pcs_replace_empty_main+0x35e/0x650 mm/slub.c:4811 alloc_from_pcs mm/slub.c:4887 [inline] slab_alloc_node mm/slub.c:5021 [inline] __do_kmalloc_node mm/slub.c:5530 [inline] __kmalloc_noprof+0x617/0x7e0 mm/slub.c:5556 _kmalloc_noprof include/linux/slab.h:995 [inline] _kzalloc_noprof include/linux/slab.h:1312 [inline] acpi_ns_internalize_name+0x161/0x2e0 drivers/acpi/acpica/nsutils.c:331 acpi_ns_get_node_unlocked+0x18c/0x500 drivers/acpi/acpica/nsutils.c:666 acpi_ns_get_node+0x6c/0xf0 drivers/acpi/acpica/nsutils.c:726 acpi_ns_evaluate+0xb01/0x1670 drivers/acpi/acpica/nseval.c:62 acpi_ut_evaluate_object+0xf7/0x610 drivers/acpi/acpica/uteval.c:60 acpi_ut_execute_power_methods+0x1f9/0x3c0 drivers/acpi/acpica/uteval.c:288 acpi_get_object_info+0xa43/0xbe0 drivers/acpi/acpica/nsxfname.c:366 acpi_set_pnp_ids drivers/acpi/scan.c:1405 [inline] acpi_init_device_object+0xc12/0x1a90 drivers/acpi/scan.c:1827 acpi_add_single_object+0xe8/0x1a10 drivers/acpi/scan.c:1877 page last free pid 1 tgid 1 ts 5222696283 stack trace: reset_page_owner include/linux/page_owner.h:26 [inline] __free_pages_prepare mm/page_alloc.c:1403 [inline] __free_frozen_pages+0x714/0xfc0 mm/page_alloc.c:2954 qlink_free mm/kasan/quarantine.c:163 [inline] qlist_free_all+0x47/0xf0 mm/kasan/quarantine.c:179 kasan_quarantine_remove_cache+0x168/0x190 mm/kasan/quarantine.c:388 kmem_cache_shrink+0xd/0x20 mm/slab_common.c:620 acpi_os_purge_cache+0x15/0x20 drivers/acpi/osl.c:1622 acpi_purge_cached_objects+0xa3/0x140 drivers/acpi/acpica/utxface.c:239 acpi_initialize_objects+0x8b/0x100 drivers/acpi/acpica/utxfinit.c:250 acpi_bus_init drivers/acpi/bus.c:1381 [inline] acpi_init+0x1b0/0x840 drivers/acpi/bus.c:1471 do_one_initcall+0x11c/0x6f0 init/main.c:1419 do_initcall_level init/main.c:1481 [inline] do_initcalls init/main.c:1497 [inline] do_basic_setup init/main.c:1517 [inline] kernel_init_freeable+0x6ea/0x7b0 init/main.c:1732 kernel_init+0x21/0x1e0 init/main.c:1622 ret_from_fork+0x69f/0xc90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Memory state around the buggy address: ffff888104ad2000: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc ffff888104ad2080: fa fc fc fc fa fc fc fc fa fc fc fc fa fc fc fc
ffff888104ad2100: 07 fc fc fc fa fc fc fc 06 fc fc fc 06 fc fc fc
^ ffff888104ad2180: 06 fc fc fc 06 fc fc fc 06 fc fc fc 06 fc fc fc ffff888104ad2200: 06 fc fc fc 06 fc fc fc fa fc fc fc fa fc fc fc ==================================================================
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