In the Linux kernel, the following vulnerability has been resolved: NFS: Fix use-after-free in nfs4_init_client() KASAN reports a use-after-free when attempting to mount two different exports through two different NICs that belong to the same server. Olga was able to hit this with kernels starting somewhere between 5.7 and 5.10, but I traced the patch that introduced the clear_bit() call to 4.13. So something must have changed in the refcounting of the clp pointer to make this call to nfs_put_client() the very last one.

In the Linux kernel, the following vulnerability has been resolved: scsi: core: Fix error handling of scsi_host_alloc() After device is initialized via device_initialize(), or its name is set via dev_set_name(), the device has to be freed via put_device(). Otherwise device name will be leaked because it is allocated dynamically in dev_set_name(). Fix the leak by replacing kfree() with put_device(). Since scsi_host_dev_release() properly handles IDA and kthread removal, remove special-casing these from the error handling as well.

In the Linux kernel, the following vulnerability has been resolved: net: ieee802154: fix null deref in parse dev addr Fix a logic error that could result in a null deref if the user sets the mode incorrectly for the given addr type.

In the Linux kernel, the following vulnerability has been resolved: mm/memory-failure: make sure wait for page writeback in memory_failure Our syzkaller trigger the "BUG_ON(!list_empty(&inode->i_wb_list))" in clear_inode: kernel BUG at fs/inode.c:519! Internal error: Oops - BUG: 0 [#1] SMP Modules linked in: Process syz-executor.0 (pid: 249, stack limit = 0x00000000a12409d7) CPU: 1 PID: 249 Comm: syz-executor.0 Not tainted 4.19.95 Hardware name: linux,dummy-virt (DT) pstate: 80000005 (Nzcv daif -PAN -UAO) pc : clear_inode+0x280/0x2a8 lr : clear_inode+0x280/0x2a8 Call trace: clear_inode+0x280/0x2a8 ext4_clear_inode+0x38/0xe8 ext4_free_inode+0x130/0xc68 ext4_evict_inode+0xb20/0xcb8 evict+0x1a8/0x3c0 iput+0x344/0x460 do_unlinkat+0x260/0x410 __arm64_sys_unlinkat+0x6c/0xc0 el0_svc_common+0xdc/0x3b0 el0_svc_handler+0xf8/0x160 el0_svc+0x10/0x218 Kernel panic - not syncing: Fatal exception A crash dump of this problem show that someone called __munlock_pagevec to clear page LRU without lock_page: do_mmap -> mmap_region -> do_munmap -> munlock_vma_pages_range -> __munlock_pagevec. As a result memory_failure will call identify_page_state without wait_on_page_writeback. And after truncate_error_page clear the mapping of this page. end_page_writeback won't call sb_clear_inode_writeback to clear inode->i_wb_list. That will trigger BUG_ON in clear_inode! Fix it by checking PageWriteback too to help determine should we skip wait_on_page_writeback.

In the Linux kernel, the following vulnerability has been resolved: kvm: LAPIC: Restore guard to prevent illegal APIC register access Per the SDM, "any access that touches bytes 4 through 15 of an APIC register may cause undefined behavior and must not be executed." Worse, such an access in kvm_lapic_reg_read can result in a leak of kernel stack contents. Prior to commit 01402cf81051 ("kvm: LAPIC: write down valid APIC registers"), such an access was explicitly disallowed. Restore the guard that was removed in that commit.

In the Linux kernel, the following vulnerability has been resolved: gfs2: Fix use-after-free in gfs2_glock_shrink_scan The GLF_LRU flag is checked under lru_lock in gfs2_glock_remove_from_lru() to remove the glock from the lru list in __gfs2_glock_put(). On the shrink scan path, the same flag is cleared under lru_lock but because of cond_resched_lock(&lru_lock) in gfs2_dispose_glock_lru(), progress on the put side can be made without deleting the glock from the lru list. Keep GLF_LRU across the race window opened by cond_resched_lock(&lru_lock) to ensure correct behavior on both sides - clear GLF_LRU after list_del under lru_lock.

In the Linux kernel, the following vulnerability has been resolved: drm/amd/display: Fix potential memory leak in DMUB hw_init [Why] On resume we perform DMUB hw_init which allocates memory: dm_resume->dm_dmub_hw_init->dc_dmub_srv_create->kzalloc That results in memory leak in suspend/resume scenarios. [How] Allocate memory for the DC wrapper to DMUB only if it was not allocated before. No need to reallocate it on suspend/resume.

In the Linux kernel, the following vulnerability has been resolved: batman-adv: Avoid WARN_ON timing related checks The soft/batadv interface for a queued OGM can be changed during the time the OGM was queued for transmission and when the OGM is actually transmitted by the worker. But WARN_ON must be used to denote kernel bugs and not to print simple warnings. A warning can simply be printed using pr_warn.

In the Linux kernel, the following vulnerability has been resolved: mac80211: fix skb length check in ieee80211_scan_rx() Replace hard-coded compile-time constants for header length check with dynamic determination based on the frame type. Otherwise, we hit a validation WARN_ON in cfg80211 later. [style fixes, reword commit message]

In the Linux kernel, the following vulnerability has been resolved: net: ipv4: fix memory leak in netlbl_cipsov4_add_std Reported by syzkaller: BUG: memory leak unreferenced object 0xffff888105df7000 (size 64): comm "syz-executor842", pid 360, jiffies 4294824824 (age 22.546s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000e67ed558>] kmalloc include/linux/slab.h:590 [inline] [<00000000e67ed558>] kzalloc include/linux/slab.h:720 [inline] [<00000000e67ed558>] netlbl_cipsov4_add_std net/netlabel/netlabel_cipso_v4.c:145 [inline] [<00000000e67ed558>] netlbl_cipsov4_add+0x390/0x2340 net/netlabel/netlabel_cipso_v4.c:416 [<0000000006040154>] genl_family_rcv_msg_doit.isra.0+0x20e/0x320 net/netlink/genetlink.c:739 [<00000000204d7a1c>] genl_family_rcv_msg net/netlink/genetlink.c:783 [inline] [<00000000204d7a1c>] genl_rcv_msg+0x2bf/0x4f0 net/netlink/genetlink.c:800 [<00000000c0d6a995>] netlink_rcv_skb+0x134/0x3d0 net/netlink/af_netlink.c:2504 [<00000000d78b9d2c>] genl_rcv+0x24/0x40 net/netlink/genetlink.c:811 [<000000009733081b>] netlink_unicast_kernel net/netlink/af_netlink.c:1314 [inline] [<000000009733081b>] netlink_unicast+0x4a0/0x6a0 net/netlink/af_netlink.c:1340 [<00000000d5fd43b8>] netlink_sendmsg+0x789/0xc70 net/netlink/af_netlink.c:1929 [<000000000a2d1e40>] sock_sendmsg_nosec net/socket.c:654 [inline] [<000000000a2d1e40>] sock_sendmsg+0x139/0x170 net/socket.c:674 [<00000000321d1969>] ____sys_sendmsg+0x658/0x7d0 net/socket.c:2350 [<00000000964e16bc>] ___sys_sendmsg+0xf8/0x170 net/socket.c:2404 [<000000001615e288>] __sys_sendmsg+0xd3/0x190 net/socket.c:2433 [<000000004ee8b6a5>] do_syscall_64+0x37/0x90 arch/x86/entry/common.c:47 [<00000000171c7cee>] entry_SYSCALL_64_after_hwframe+0x44/0xae The memory of doi_def->map.std pointing is allocated in netlbl_cipsov4_add_std, but no place has freed it. It should be freed in cipso_v4_doi_free which frees the cipso DOI resource.

In the Linux kernel, the following vulnerability has been resolved: net: rds: fix memory leak in rds_recvmsg Syzbot reported memory leak in rds. The problem was in unputted refcount in case of error. int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size, int msg_flags) { ... if (!rds_next_incoming(rs, &inc)) { ... } After this "if" inc refcount incremented and if (rds_cmsg_recv(inc, msg, rs)) { ret = -EFAULT; goto out; } ... out: return ret; } in case of rds_cmsg_recv() fail the refcount won't be decremented. And it's easy to see from ftrace log, that rds_inc_addref() don't have rds_inc_put() pair in rds_recvmsg() after rds_cmsg_recv() 1) | rds_recvmsg() { 1) 3.721 us | rds_inc_addref(); 1) 3.853 us | rds_message_inc_copy_to_user(); 1) + 10.395 us | rds_cmsg_recv(); 1) + 34.260 us | }

In the Linux kernel, the following vulnerability has been resolved: udp: fix race between close() and udp_abort() Kaustubh reported and diagnosed a panic in udp_lib_lookup(). The root cause is udp_abort() racing with close(). Both racing functions acquire the socket lock, but udp{v6}_destroy_sock() release it before performing destructive actions. We can't easily extend the socket lock scope to avoid the race, instead use the SOCK_DEAD flag to prevent udp_abort from doing any action when the critical race happens. Diagnosed-and-tested-by: Kaustubh Pandey <kapandey@codeaurora.org>

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix use-after-free of encap entry in neigh update handler Function mlx5e_rep_neigh_update() wasn't updated to accommodate rtnl lock removal from TC filter update path and properly handle concurrent encap entry insertion/deletion which can lead to following use-after-free: [23827.464923] ================================================================== [23827.469446] BUG: KASAN: use-after-free in mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.470971] Read of size 4 at addr ffff8881d132228c by task kworker/u20:6/21635 [23827.472251] [23827.472615] CPU: 9 PID: 21635 Comm: kworker/u20:6 Not tainted 5.13.0-rc3+ #5 [23827.473788] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [23827.475639] Workqueue: mlx5e mlx5e_rep_neigh_update [mlx5_core] [23827.476731] Call Trace: [23827.477260] dump_stack+0xbb/0x107 [23827.477906] print_address_description.constprop.0+0x18/0x140 [23827.478896] ? mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.479879] ? mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.480905] kasan_report.cold+0x7c/0xd8 [23827.481701] ? mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.482744] kasan_check_range+0x145/0x1a0 [23827.493112] mlx5e_encap_take+0x72/0x140 [mlx5_core] [23827.494054] ? mlx5e_tc_tun_encap_info_equal_generic+0x140/0x140 [mlx5_core] [23827.495296] mlx5e_rep_neigh_update+0x41e/0x5e0 [mlx5_core] [23827.496338] ? mlx5e_rep_neigh_entry_release+0xb80/0xb80 [mlx5_core] [23827.497486] ? read_word_at_a_time+0xe/0x20 [23827.498250] ? strscpy+0xa0/0x2a0 [23827.498889] process_one_work+0x8ac/0x14e0 [23827.499638] ? lockdep_hardirqs_on_prepare+0x400/0x400 [23827.500537] ? pwq_dec_nr_in_flight+0x2c0/0x2c0 [23827.501359] ? rwlock_bug.part.0+0x90/0x90 [23827.502116] worker_thread+0x53b/0x1220 [23827.502831] ? process_one_work+0x14e0/0x14e0 [23827.503627] kthread+0x328/0x3f0 [23827.504254] ? _raw_spin_unlock_irq+0x24/0x40 [23827.505065] ? __kthread_bind_mask+0x90/0x90 [23827.505912] ret_from_fork+0x1f/0x30 [23827.506621] [23827.506987] Allocated by task 28248: [23827.507694] kasan_save_stack+0x1b/0x40 [23827.508476] __kasan_kmalloc+0x7c/0x90 [23827.509197] mlx5e_attach_encap+0xde1/0x1d40 [mlx5_core] [23827.510194] mlx5e_tc_add_fdb_flow+0x397/0xc40 [mlx5_core] [23827.511218] __mlx5e_add_fdb_flow+0x519/0xb30 [mlx5_core] [23827.512234] mlx5e_configure_flower+0x191c/0x4870 [mlx5_core] [23827.513298] tc_setup_cb_add+0x1d5/0x420 [23827.514023] fl_hw_replace_filter+0x382/0x6a0 [cls_flower] [23827.514975] fl_change+0x2ceb/0x4a51 [cls_flower] [23827.515821] tc_new_tfilter+0x89a/0x2070 [23827.516548] rtnetlink_rcv_msg+0x644/0x8c0 [23827.517300] netlink_rcv_skb+0x11d/0x340 [23827.518021] netlink_unicast+0x42b/0x700 [23827.518742] netlink_sendmsg+0x743/0xc20 [23827.519467] sock_sendmsg+0xb2/0xe0 [23827.520131] ____sys_sendmsg+0x590/0x770 [23827.520851] ___sys_sendmsg+0xd8/0x160 [23827.521552] __sys_sendmsg+0xb7/0x140 [23827.522238] do_syscall_64+0x3a/0x70 [23827.522907] entry_SYSCALL_64_after_hwframe+0x44/0xae [23827.523797] [23827.524163] Freed by task 25948: [23827.524780] kasan_save_stack+0x1b/0x40 [23827.525488] kasan_set_track+0x1c/0x30 [23827.526187] kasan_set_free_info+0x20/0x30 [23827.526968] __kasan_slab_free+0xed/0x130 [23827.527709] slab_free_freelist_hook+0xcf/0x1d0 [23827.528528] kmem_cache_free_bulk+0x33a/0x6e0 [23827.529317] kfree_rcu_work+0x55f/0xb70 [23827.530024] process_one_work+0x8ac/0x14e0 [23827.530770] worker_thread+0x53b/0x1220 [23827.531480] kthread+0x328/0x3f0 [23827.532114] ret_from_fork+0x1f/0x30 [23827.532785] [23827.533147] Last potentially related work creation: [23827.534007] kasan_save_stack+0x1b/0x40 [23827.534710] kasan_record_aux_stack+0xab/0xc0 [23827.535492] kvfree_call_rcu+0x31/0x7b0 [23827.536206] mlx5e_tc_del ---truncated---

In the Linux kernel, the following vulnerability has been resolved: net/mlx5e: Fix page reclaim for dead peer hairpin When adding a hairpin flow, a firmware-side send queue is created for the peer net device, which claims some host memory pages for its internal ring buffer. If the peer net device is removed/unbound before the hairpin flow is deleted, then the send queue is not destroyed which leads to a stack trace on pci device remove: [ 748.005230] mlx5_core 0000:08:00.2: wait_func:1094:(pid 12985): MANAGE_PAGES(0x108) timeout. Will cause a leak of a command resource [ 748.005231] mlx5_core 0000:08:00.2: reclaim_pages:514:(pid 12985): failed reclaiming pages: err -110 [ 748.001835] mlx5_core 0000:08:00.2: mlx5_reclaim_root_pages:653:(pid 12985): failed reclaiming pages (-110) for func id 0x0 [ 748.002171] ------------[ cut here ]------------ [ 748.001177] FW pages counter is 4 after reclaiming all pages [ 748.001186] WARNING: CPU: 1 PID: 12985 at drivers/net/ethernet/mellanox/mlx5/core/pagealloc.c:685 mlx5_reclaim_startup_pages+0x34b/0x460 [mlx5_core] [ +0.002771] Modules linked in: cls_flower mlx5_ib mlx5_core ptp pps_core act_mirred sch_ingress openvswitch nsh xt_conntrack xt_MASQUERADE nf_conntrack_netlink nfnetlink xt_addrtype iptable_nat nf_nat nf_conntrack nf_defrag_ipv6 nf_defrag_ipv4 br_netfilter rpcrdma rdma_ucm ib_iser libiscsi scsi_transport_iscsi rdma_cm ib_umad ib_ipoib iw_cm ib_cm ib_uverbs ib_core overlay fuse [last unloaded: pps_core] [ 748.007225] CPU: 1 PID: 12985 Comm: tee Not tainted 5.12.0+ #1 [ 748.001376] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.13.0-0-gf21b5a4aeb02-prebuilt.qemu.org 04/01/2014 [ 748.002315] RIP: 0010:mlx5_reclaim_startup_pages+0x34b/0x460 [mlx5_core] [ 748.001679] Code: 28 00 00 00 0f 85 22 01 00 00 48 81 c4 b0 00 00 00 31 c0 5b 5d 41 5c 41 5d 41 5e 41 5f c3 48 c7 c7 40 cc 19 a1 e8 9f 71 0e e2 <0f> 0b e9 30 ff ff ff 48 c7 c7 a0 cc 19 a1 e8 8c 71 0e e2 0f 0b e9 [ 748.003781] RSP: 0018:ffff88815220faf8 EFLAGS: 00010286 [ 748.001149] RAX: 0000000000000000 RBX: ffff8881b4900280 RCX: 0000000000000000 [ 748.001445] RDX: 0000000000000027 RSI: 0000000000000004 RDI: ffffed102a441f51 [ 748.001614] RBP: 00000000000032b9 R08: 0000000000000001 R09: ffffed1054a15ee8 [ 748.001446] R10: ffff8882a50af73b R11: ffffed1054a15ee7 R12: fffffbfff07c1e30 [ 748.001447] R13: dffffc0000000000 R14: ffff8881b492cba8 R15: 0000000000000000 [ 748.001429] FS: 00007f58bd08b580(0000) GS:ffff8882a5080000(0000) knlGS:0000000000000000 [ 748.001695] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 748.001309] CR2: 000055a026351740 CR3: 00000001d3b48006 CR4: 0000000000370ea0 [ 748.001506] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 748.001483] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 748.001654] Call Trace: [ 748.000576] ? mlx5_satisfy_startup_pages+0x290/0x290 [mlx5_core] [ 748.001416] ? mlx5_cmd_teardown_hca+0xa2/0xd0 [mlx5_core] [ 748.001354] ? mlx5_cmd_init_hca+0x280/0x280 [mlx5_core] [ 748.001203] mlx5_function_teardown+0x30/0x60 [mlx5_core] [ 748.001275] mlx5_uninit_one+0xa7/0xc0 [mlx5_core] [ 748.001200] remove_one+0x5f/0xc0 [mlx5_core] [ 748.001075] pci_device_remove+0x9f/0x1d0 [ 748.000833] device_release_driver_internal+0x1e0/0x490 [ 748.001207] unbind_store+0x19f/0x200 [ 748.000942] ? sysfs_file_ops+0x170/0x170 [ 748.001000] kernfs_fop_write_iter+0x2bc/0x450 [ 748.000970] new_sync_write+0x373/0x610 [ 748.001124] ? new_sync_read+0x600/0x600 [ 748.001057] ? lock_acquire+0x4d6/0x700 [ 748.000908] ? lockdep_hardirqs_on_prepare+0x400/0x400 [ 748.001126] ? fd_install+0x1c9/0x4d0 [ 748.000951] vfs_write+0x4d0/0x800 [ 748.000804] ksys_write+0xf9/0x1d0 [ 748.000868] ? __x64_sys_read+0xb0/0xb0 [ 748.000811] ? filp_open+0x50/0x50 [ 748.000919] ? syscall_enter_from_user_mode+0x1d/0x50 [ 748.001223] do_syscall_64+0x3f/0x80 [ 748.000892] entry_SYSCALL_64_after_hwframe+0x44/0xae [ 748.00 ---truncated---

In the Linux kernel, the following vulnerability has been resolved: netfilter: synproxy: Fix out of bounds when parsing TCP options The TCP option parser in synproxy (synproxy_parse_options) could read one byte out of bounds. When the length is 1, the execution flow gets into the loop, reads one byte of the opcode, and if the opcode is neither TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the length of 1. This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack out of bounds when parsing TCP options."). v2 changes: Added an early return when length < 0 to avoid calling skb_header_pointer with negative length.

In the Linux kernel, the following vulnerability has been resolved: mptcp: Fix out of bounds when parsing TCP options The TCP option parser in mptcp (mptcp_get_options) could read one byte out of bounds. When the length is 1, the execution flow gets into the loop, reads one byte of the opcode, and if the opcode is neither TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the length of 1. This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack out of bounds when parsing TCP options.").

In the Linux kernel, the following vulnerability has been resolved: sch_cake: Fix out of bounds when parsing TCP options and header The TCP option parser in cake qdisc (cake_get_tcpopt and cake_tcph_may_drop) could read one byte out of bounds. When the length is 1, the execution flow gets into the loop, reads one byte of the opcode, and if the opcode is neither TCPOPT_EOL nor TCPOPT_NOP, it reads one more byte, which exceeds the length of 1. This fix is inspired by commit 9609dad263f8 ("ipv4: tcp_input: fix stack out of bounds when parsing TCP options."). v2 changes: Added doff validation in cake_get_tcphdr to avoid parsing garbage as TCP header. Although it wasn't strictly an out-of-bounds access (memory was allocated), garbage values could be read where CAKE expected the TCP header if doff was smaller than 5.

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix soft lookup in subflow_error_report() Maxim reported a soft lookup in subflow_error_report(): watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:0] RIP: 0010:native_queued_spin_lock_slowpath RSP: 0018:ffffa859c0003bc0 EFLAGS: 00000202 RAX: 0000000000000101 RBX: 0000000000000001 RCX: 0000000000000000 RDX: ffff9195c2772d88 RSI: 0000000000000000 RDI: ffff9195c2772d88 RBP: ffff9195c2772d00 R08: 00000000000067b0 R09: c6e31da9eb1e44f4 R10: ffff9195ef379700 R11: ffff9195edb50710 R12: ffff9195c2772d88 R13: ffff9195f500e3d0 R14: ffff9195ef379700 R15: ffff9195ef379700 FS: 0000000000000000(0000) GS:ffff91961f400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c000407000 CR3: 0000000002988000 CR4: 00000000000006f0 Call Trace: <IRQ> _raw_spin_lock_bh subflow_error_report mptcp_subflow_data_available __mptcp_move_skbs_from_subflow mptcp_data_ready tcp_data_queue tcp_rcv_established tcp_v4_do_rcv tcp_v4_rcv ip_protocol_deliver_rcu ip_local_deliver_finish __netif_receive_skb_one_core netif_receive_skb rtl8139_poll 8139too __napi_poll net_rx_action __do_softirq __irq_exit_rcu common_interrupt </IRQ> The calling function - mptcp_subflow_data_available() - can be invoked from different contexts: - plain ssk socket lock - ssk socket lock + mptcp_data_lock - ssk socket lock + mptcp_data_lock + msk socket lock. Since subflow_error_report() tries to acquire the mptcp_data_lock, the latter two call chains will cause soft lookup. This change addresses the issue moving the error reporting call to outer functions, where the held locks list is known and the we can acquire only the needed one.

In the Linux kernel, the following vulnerability has been resolved: ethtool: strset: fix message length calculation Outer nest for ETHTOOL_A_STRSET_STRINGSETS is not accounted for. This may result in ETHTOOL_MSG_STRSET_GET producing a warning like: calculated message payload length (684) not sufficient WARNING: CPU: 0 PID: 30967 at net/ethtool/netlink.c:369 ethnl_default_doit+0x87a/0xa20 and a splat. As usually with such warnings three conditions must be met for the warning to trigger: - there must be no skb size rounding up (e.g. reply_size of 684); - string set must be per-device (so that the header gets populated); - the device name must be at least 12 characters long. all in all with current user space it looks like reading priv flags is the only place this could potentially happen. Or with syzbot :)

In the Linux kernel, the following vulnerability has been resolved: net: qrtr: fix OOB Read in qrtr_endpoint_post Syzbot reported slab-out-of-bounds Read in qrtr_endpoint_post. The problem was in wrong _size_ type: if (len != ALIGN(size, 4) + hdrlen) goto err; If size from qrtr_hdr is 4294967293 (0xfffffffd), the result of ALIGN(size, 4) will be 0. In case of len == hdrlen and size == 4294967293 in header this check won't fail and skb_put_data(skb, data + hdrlen, size); will read out of bound from data, which is hdrlen allocated block.