NULL Pointer Dereference

In the Linux kernel, the following vulnerability has been resolved: firmware: dmi-sysfs: Fix null-ptr-deref in dmi_sysfs_register_handle KASAN reported a null-ptr-deref error: KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] CPU: 0 PID: 1373 Comm: modprobe Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:dmi_sysfs_entry_release ... Call Trace: <TASK> kobject_put dmi_sysfs_register_handle (drivers/firmware/dmi-sysfs.c:540) dmi_sysfs dmi_decode_table (drivers/firmware/dmi_scan.c:133) dmi_walk (drivers/firmware/dmi_scan.c:1115) dmi_sysfs_init (drivers/firmware/dmi-sysfs.c:149) dmi_sysfs do_one_initcall (init/main.c:1296) ... Kernel panic - not syncing: Fatal exception Kernel Offset: 0x4000000 from 0xffffffff81000000 ---[ end Kernel panic - not syncing: Fatal exception ]--- It is because previous patch added kobject_put() to release the memory which will call dmi_sysfs_entry_release() and list_del(). However, list_add_tail(entry->list) is called after the error block, so the list_head is uninitialized and cannot be deleted. Move error handling to after list_add_tail to fix this.Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: install stub fence into potential unused fence pointers When using cpu to update page tables, vm update fences are unused. Install stub fence into these fence pointers instead of NULL to avoid NULL dereference when calling dma_fence_wait() on them.Show less

In the Linux kernel, the following vulnerability has been resolved: cifs: fix DFS traversal oops without CONFIG_CIFS_DFS_UPCALL When compiled with CONFIG_CIFS_DFS_UPCALL disabled, cifs_dfs_d_automount is NULL. cifs.ko logic for mapping CIFS_FATTR_DFS_REFERRAL attributes to S_AUTOMOUNT and corresponding dentry flags is retained regardless of CONFIG_CIFS_DFS_UPCALL, leading to a NULL pointer dereference in VFS follow_automount() when traversing a DFS referral link: BUG: kernel NULL pointer dereference, address: 0000000000000000 ... Call Trace: <TASK> __traverse_mounts+0xb5/0x220 ? cifs_revalidate_mapping+0x65/0xc0 [cifs] step_into+0x195/0x610 ? lookup_fast+0xe2/0xf0 path_lookupat+0x64/0x140 filename_lookup+0xc2/0x140 ? __create_object+0x299/0x380 ? kmem_cache_alloc+0x119/0x220 ? user_path_at_empty+0x31/0x50 user_path_at_empty+0x31/0x50 __x64_sys_chdir+0x2a/0xd0 ? exit_to_user_mode_prepare+0xca/0x100 do_syscall_64+0x42/0x90 entry_SYSCALL_64_after_hwframe+0x72/0xdc This fix adds an inline cifs_dfs_d_automount() {return -EREMOTE} handler when CONFIG_CIFS_DFS_UPCALL is disabled. An alternative would be to avoid flagging S_AUTOMOUNT, etc. without CONFIG_CIFS_DFS_UPCALL. This approach was chosen as it provides more control over the error path.Show less

In the Linux kernel, the following vulnerability has been resolved: scsi: storvsc: Fix handling of virtual Fibre Channel timeouts Hyper-V provides the ability to connect Fibre Channel LUNs to the host system and present them in a guest VM as a SCSI device. I/O to the vFC device is handled by the storvsc driver. The storvsc driver includes a partial integration with the FC transport implemented in the generic portion of the Linux SCSI subsystem so that FC attributes can be displayed in /sys. However, the partial integration means that some aspects of vFC don't work properly. Unfortunately, a full and correct integration isn't practical because of limitations in what Hyper-V provides to the guest. In particular, in the context of Hyper-V storvsc, the FC transport timeout function fc_eh_timed_out() causes a kernel panic because it can't find the rport and dereferences a NULL pointer. The original patch that added the call from storvsc_eh_timed_out() to fc_eh_timed_out() is faulty in this regard. In many cases a timeout is due to a transient condition, so the situation can be improved by just continuing to wait like with other I/O requests issued by storvsc, and avoiding the guaranteed panic. For a permanent failure, continuing to wait may result in a hung thread instead of a panic, which again may be better. So fix the panic by removing the storvsc call to fc_eh_timed_out(). This allows storvsc to keep waiting for a response. The change has been tested by users who experienced a panic in fc_eh_timed_out() due to transient timeouts, and it solves their problem. In the future we may want to deprecate the vFC functionality in storvsc since it can't be fully fixed. But it has current users for whom it is working well enough, so it should probably stay for a while longer.Show less

In the Linux kernel, the following vulnerability has been resolved: media: pci: tw68: Fix null-ptr-deref bug in buf prepare and finish When the driver calls tw68_risc_buffer() to prepare the buffer, the function call dma_alloc_coherent may fail, resulting in a empty buffer buf->cpu. Later when we free the buffer or access the buffer, null ptr deref is triggered. This bug is similar to the following one: https://git.linuxtv.org/media_stage.git/commit/?id=2b064d91440b33fba5b452f2d1b31f13ae911d71. We believe the bug can be also dynamically triggered from user side. Similarly, we fix this by checking the return value of tw68_risc_buffer() and the value of buf->cpu before buffer free.Show less

In the Linux kernel, the following vulnerability has been resolved: xsk: check IFF_UP earlier in Tx path Xsk Tx can be triggered via either sendmsg() or poll() syscalls. These two paths share a call to common function xsk_xmit() which has two sanity checks within. A pseudo code example to show the two paths: __xsk_sendmsg() : xsk_poll(): if (unlikely(!xsk_is_bound(xs))) if (unlikely(!xsk_is_bound(xs))) return -ENXIO; return mask; if (unlikely(need_wait)) (...) return -EOPNOTSUPP; xsk_xmit() mark napi id (...) xsk_xmit() xsk_xmit(): if (unlikely(!(xs->dev->flags & IFF_UP))) return -ENETDOWN; if (unlikely(!xs->tx)) return -ENOBUFS; As it can be observed above, in sendmsg() napi id can be marked on interface that was not brought up and this causes a NULL ptr dereference: [31757.505631] BUG: kernel NULL pointer dereference, address: 0000000000000018 [31757.512710] #PF: supervisor read access in kernel mode [31757.517936] #PF: error_code(0x0000) - not-present page [31757.523149] PGD 0 P4D 0 [31757.525726] Oops: 0000 [#1] PREEMPT SMP NOPTI [31757.530154] CPU: 26 PID: 95641 Comm: xdpsock Not tainted 6.2.0-rc5+ #40 [31757.536871] Hardware name: Intel Corporation S2600WFT/S2600WFT, BIOS SE5C620.86B.02.01.0008.031920191559 03/19/2019 [31757.547457] RIP: 0010:xsk_sendmsg+0xde/0x180 [31757.551799] Code: 00 75 a2 48 8b 00 a8 04 75 9b 84 d2 74 69 8b 85 14 01 00 00 85 c0 75 1b 48 8b 85 28 03 00 00 48 8b 80 98 00 00 00 48 8b 40 20 <8b> 40 18 89 85 14 01 00 00 8b bd 14 01 00 00 81 ff 00 01 00 00 0f [31757.570840] RSP: 0018:ffffc90034f27dc0 EFLAGS: 00010246 [31757.576143] RAX: 0000000000000000 RBX: ffffc90034f27e18 RCX: 0000000000000000 [31757.583389] RDX: 0000000000000001 RSI: ffffc90034f27e18 RDI: ffff88984cf3c100 [31757.590631] RBP: ffff88984714a800 R08: ffff88984714a800 R09: 0000000000000000 [31757.597877] R10: 0000000000000001 R11: 0000000000000000 R12: 00000000fffffffa [31757.605123] R13: 0000000000000000 R14: 0000000000000003 R15: 0000000000000000 [31757.612364] FS: 00007fb4c5931180(0000) GS:ffff88afdfa00000(0000) knlGS:0000000000000000 [31757.620571] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [31757.626406] CR2: 0000000000000018 CR3: 000000184b41c003 CR4: 00000000007706e0 [31757.633648] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [31757.640894] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [31757.648139] PKRU: 55555554 [31757.650894] Call Trace: [31757.653385] <TASK> [31757.655524] sock_sendmsg+0x8f/0xa0 [31757.659077] ? sockfd_lookup_light+0x12/0x70 [31757.663416] __sys_sendto+0xfc/0x170 [31757.667051] ? do_sched_setscheduler+0xdb/0x1b0 [31757.671658] __x64_sys_sendto+0x20/0x30 [31757.675557] do_syscall_64+0x38/0x90 [31757.679197] entry_SYSCALL_64_after_hwframe+0x72/0xdc [31757.687969] Code: 8e f6 ff 44 8b 4c 24 2c 4c 8b 44 24 20 41 89 c4 44 8b 54 24 28 48 8b 54 24 18 b8 2c 00 00 00 48 8b 74 24 10 8b 7c 24 08 0f 05 <48> 3d 00 f0 ff ff 77 3a 44 89 e7 48 89 44 24 08 e8 b5 8e f6 ff 48 [31757.707007] RSP: 002b:00007ffd49c73c70 EFLAGS: 00000293 ORIG_RAX: 000000000000002c [31757.714694] RAX: ffffffffffffffda RBX: 000055a996565380 RCX: 00007fb4c5727c16 [31757.721939] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000003 [31757.729184] RBP: 0000000000000040 R08: 0000000000000000 R09: 0000000000000000 [31757.736429] R10: 0000000000000040 R11: 0000000000000293 R12: 0000000000000000 [31757.743673] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [31757.754940] </TASK> To fix this, let's make xsk_xmit a function that will be responsible for generic Tx, where RCU is handled accordingly and pull out sanity checks and xs->zc handling. Populate sanity checks to __xsk_sendmsg() and xsk_poll().Show less

In the Linux kernel, the following vulnerability has been resolved: drm/msm/mdp5: Add check for kzalloc As kzalloc may fail and return NULL pointer, it should be better to check the return value in order to avoid the NULL pointer dereference. Patchwork: https://patchwork.freedesktop.org/patch/514154/Show less

In the Linux kernel, the following vulnerability has been resolved: drm/amdgpu: drop redundant sched job cleanup when cs is aborted Once command submission failed due to userptr invalidation in amdgpu_cs_submit, legacy code will perform cleanup of scheduler job. However, it's not needed at all, as former commit has integrated job cleanup stuff into amdgpu_job_free. Otherwise, because of double free, a NULL pointer dereference will occur in such scenario. Bug: https://gitlab.freedesktop.org/drm/amd/-/issues/2457Show less

In the Linux kernel, the following vulnerability has been resolved: drm/msm/dsi: Add missing check for alloc_ordered_workqueue Add check for the return value of alloc_ordered_workqueue as it may return NULL pointer and cause NULL pointer dereference. Patchwork: https://patchwork.freedesktop.org/patch/517646/Show less

In the Linux kernel, the following vulnerability has been resolved: media: az6007: Fix null-ptr-deref in az6007_i2c_xfer() In az6007_i2c_xfer, msg is controlled by user. When msg[i].buf is null and msg[i].len is zero, former checks on msg[i].buf would be passed. Malicious data finally reach az6007_i2c_xfer. If accessing msg[i].buf[0] without sanity check, null ptr deref would happen. We add check on msg[i].len to prevent crash. Similar commit: commit 0ed554fd769a ("media: dvb-usb: az6027: fix null-ptr-deref in az6027_i2c_xfer()")Show less

In the Linux kernel, the following vulnerability has been resolved: md/raid5-cache: fix null-ptr-deref for r5l_flush_stripe_to_raid() r5l_flush_stripe_to_raid() will check if the list 'flushing_ios' is empty, and then submit 'flush_bio', however, r5l_log_flush_endio() is clearing the list first and then clear the bio, which will cause null-ptr-deref: T1: submit flush io raid5d handle_active_stripes r5l_flush_stripe_to_raid // list is empty // add 'io_end_ios' to the list bio_init submit_bio // io1 T2: io1 is done r5l_log_flush_endio list_splice_tail_init // clear the list T3: submit new flush io ... r5l_flush_stripe_to_raid // list is empty // add 'io_end_ios' to the list bio_init bio_uninit // clear bio->bi_blkg submit_bio // null-ptr-deref Fix this problem by clearing bio before clearing the list in r5l_log_flush_endio().Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211_hwsim: Fix possible NULL dereference In a call to mac80211_hwsim_select_tx_link() the sta pointer might be NULL, thus need to check that it is not NULL before accessing it.Show less

In the Linux kernel, the following vulnerability has been resolved: hwmon: (pmbus_core) Fix NULL pointer dereference Pass i2c_client to _pmbus_is_enabled to drop the assumption that a regulator device is passed in. This will fix the issue of a NULL pointer dereference when called from _pmbus_get_flags.Show less

In the Linux kernel, the following vulnerability has been resolved: wifi: mt76: mt7996: rely on mt76_connac2_mac_tx_rate_val In order to fix a possible NULL pointer dereference in mt7996_mac_write_txwi() of vif pointer, export mt76_connac2_mac_tx_rate_val utility routine and reuse it in mt7996 driver.Show less

In the Linux kernel, the following vulnerability has been resolved: fs/ntfs3: Add null pointer check to attr_load_runs_vcn Some metadata files are handled before MFT. This adds a null pointer check for some corner cases that could lead to NPD while reading these metadata files for a malformed NTFS image. [ 240.190827] BUG: kernel NULL pointer dereference, address: 0000000000000158 [ 240.191583] #PF: supervisor read access in kernel mode [ 240.191956] #PF: error_code(0x0000) - not-present page [ 240.192391] PGD 0 P4D 0 [ 240.192897] Oops: 0000 [#1] PREEMPT SMP KASAN NOPTI [ 240.193805] CPU: 0 PID: 242 Comm: mount Tainted: G B 5.19.0+ #17 [ 240.194477] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.14.0-0-g155821a1990b-prebuilt.qemu.org 04/01/2014 [ 240.195152] RIP: 0010:ni_find_attr+0xae/0x300 [ 240.195679] Code: c8 48 c7 45 88 c0 4e 5e 86 c7 00 f1 f1 f1 f1 c7 40 04 00 f3 f3 f3 65 48 8b 04 25 28 00 00 00 48 89 45 d0 31 c0 e8 e2 d9f [ 240.196642] RSP: 0018:ffff88800812f690 EFLAGS: 00000286 [ 240.197019] RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff85ef037a [ 240.197523] RDX: 0000000000000001 RSI: 0000000000000008 RDI: ffffffff88e95f60 [ 240.197877] RBP: ffff88800812f738 R08: 0000000000000001 R09: fffffbfff11d2bed [ 240.198292] R10: ffffffff88e95f67 R11: fffffbfff11d2bec R12: 0000000000000000 [ 240.198647] R13: 0000000000000080 R14: 0000000000000000 R15: 0000000000000000 [ 240.199410] FS: 00007f233c33be40(0000) GS:ffff888058200000(0000) knlGS:0000000000000000 [ 240.199895] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 240.200314] CR2: 0000000000000158 CR3: 0000000004d32000 CR4: 00000000000006f0 [ 240.200839] Call Trace: [ 240.201104] <TASK> [ 240.201502] ? ni_load_mi+0x80/0x80 [ 240.202297] ? ___slab_alloc+0x465/0x830 [ 240.202614] attr_load_runs_vcn+0x8c/0x1a0 [ 240.202886] ? __kasan_slab_alloc+0x32/0x90 [ 240.203157] ? attr_data_write_resident+0x250/0x250 [ 240.203543] mi_read+0x133/0x2c0 [ 240.203785] mi_get+0x70/0x140 [ 240.204012] ni_load_mi_ex+0xfa/0x190 [ 240.204346] ? ni_std5+0x90/0x90 [ 240.204588] ? __kasan_kmalloc+0x88/0xb0 [ 240.204859] ni_enum_attr_ex+0xf1/0x1c0 [ 240.205107] ? ni_fname_type.part.0+0xd0/0xd0 [ 240.205600] ? ntfs_load_attr_list+0xbe/0x300 [ 240.205864] ? ntfs_cmp_names_cpu+0x125/0x180 [ 240.206157] ntfs_iget5+0x56c/0x1870 [ 240.206510] ? ntfs_get_block_bmap+0x70/0x70 [ 240.206776] ? __kasan_kmalloc+0x88/0xb0 [ 240.207030] ? set_blocksize+0x95/0x150 [ 240.207545] ntfs_fill_super+0xb8f/0x1e20 [ 240.207839] ? put_ntfs+0x1d0/0x1d0 [ 240.208069] ? vsprintf+0x20/0x20 [ 240.208467] ? mutex_unlock+0x81/0xd0 [ 240.208846] ? set_blocksize+0x95/0x150 [ 240.209221] get_tree_bdev+0x232/0x370 [ 240.209804] ? put_ntfs+0x1d0/0x1d0 [ 240.210519] ntfs_fs_get_tree+0x15/0x20 [ 240.210991] vfs_get_tree+0x4c/0x130 [ 240.211455] path_mount+0x645/0xfd0 [ 240.211806] ? putname+0x80/0xa0 [ 240.212112] ? finish_automount+0x2e0/0x2e0 [ 240.212559] ? kmem_cache_free+0x110/0x390 [ 240.212906] ? putname+0x80/0xa0 [ 240.213329] do_mount+0xd6/0xf0 [ 240.213829] ? path_mount+0xfd0/0xfd0 [ 240.214246] ? __kasan_check_write+0x14/0x20 [ 240.214774] __x64_sys_mount+0xca/0x110 [ 240.215080] do_syscall_64+0x3b/0x90 [ 240.215442] entry_SYSCALL_64_after_hwframe+0x63/0xcd [ 240.215811] RIP: 0033:0x7f233b4e948a [ 240.216104] Code: 48 8b 0d 11 fa 2a 00 f7 d8 64 89 01 48 83 c8 ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 44 00 00 49 89 ca b8 a5 00 00 008 [ 240.217615] RSP: 002b:00007fff02211ec8 EFLAGS: 00000202 ORIG_RAX: 00000000000000a5 [ 240.218718] RAX: ffffffffffffffda RBX: 0000561cdc35b060 RCX: 00007f233b4e948a [ 240.219556] RDX: 0000561cdc35b260 RSI: 0000561cdc35b2e0 RDI: 0000561cdc363af0 [ 240.219975] RBP: 0000000000000000 R08: 0000561cdc35b280 R09: 0000000000000020 [ 240.220403] R10: 00000000c0ed0000 R11: 0000000000000202 R12: 0000561cdc363af0 [ 240.220803] R13: 000 ---truncated---Show less

In the Linux kernel, the following vulnerability has been resolved: hugetlbfs: fix null-ptr-deref in hugetlbfs_parse_param() Syzkaller reports a null-ptr-deref bug as follows: ====================================================== KASAN: null-ptr-deref in range [0x0000000000000000-0x0000000000000007] RIP: 0010:hugetlbfs_parse_param+0x1dd/0x8e0 fs/hugetlbfs/inode.c:1380 [...] Call Trace: <TASK> vfs_parse_fs_param fs/fs_context.c:148 [inline] vfs_parse_fs_param+0x1f9/0x3c0 fs/fs_context.c:129 vfs_parse_fs_string+0xdb/0x170 fs/fs_context.c:191 generic_parse_monolithic+0x16f/0x1f0 fs/fs_context.c:231 do_new_mount fs/namespace.c:3036 [inline] path_mount+0x12de/0x1e20 fs/namespace.c:3370 do_mount fs/namespace.c:3383 [inline] __do_sys_mount fs/namespace.c:3591 [inline] __se_sys_mount fs/namespace.c:3568 [inline] __x64_sys_mount+0x27f/0x300 fs/namespace.c:3568 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd [...] </TASK> ====================================================== According to commit "vfs: parse: deal with zero length string value", kernel will set the param->string to null pointer in vfs_parse_fs_string() if fs string has zero length. Yet the problem is that, hugetlbfs_parse_param() will dereference the param->string, without checking whether it is a null pointer. To be more specific, if hugetlbfs_parse_param() parses an illegal mount parameter, such as "size=,", kernel will constructs struct fs_parameter with null pointer in vfs_parse_fs_string(), then passes this struct fs_parameter to hugetlbfs_parse_param(), which triggers the above null-ptr-deref bug. This patch solves it by adding sanity check on param->string in hugetlbfs_parse_param().Show less

In the Linux kernel, the following vulnerability has been resolved: ACPI: processor: idle: Check acpi_fetch_acpi_dev() return value The return value of acpi_fetch_acpi_dev() could be NULL, which would cause a NULL pointer dereference to occur in acpi_device_hid(). [ rjw: Subject and changelog edits, added empty line after if () ]Show less

In the Linux kernel, the following vulnerability has been resolved: drm/bridge: megachips: Fix a null pointer dereference bug When removing the module we will get the following warning: [ 31.911505] i2c-core: driver [stdp2690-ge-b850v3-fw] unregistered [ 31.912484] general protection fault, probably for non-canonical address 0xdffffc0000000001: 0000 [#1] PREEMPT SMP KASAN PTI [ 31.913338] KASAN: null-ptr-deref in range [0x0000000000000008-0x000000000000000f] [ 31.915280] RIP: 0010:drm_bridge_remove+0x97/0x130 [ 31.921825] Call Trace: [ 31.922533] stdp4028_ge_b850v3_fw_remove+0x34/0x60 [megachips_stdpxxxx_ge_b850v3_fw] [ 31.923139] i2c_device_remove+0x181/0x1f0 The two bridges (stdp2690, stdp4028) do not probe at the same time, so the driver does not call ge_b850v3_resgiter() when probing, causing the driver to try to remove the object that has not been initialized. Fix this by checking whether both the bridges are probed.Show less

In the Linux kernel, the following vulnerability has been resolved: io_uring/msg_ring: Fix NULL pointer dereference in io_msg_send_fd() Syzkaller produced the below call trace: BUG: KASAN: null-ptr-deref in io_msg_ring+0x3cb/0x9f0 Write of size 8 at addr 0000000000000070 by task repro/16399 CPU: 0 PID: 16399 Comm: repro Not tainted 6.1.0-rc1 #28 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 Call Trace: <TASK> dump_stack_lvl+0xcd/0x134 ? io_msg_ring+0x3cb/0x9f0 kasan_report+0xbc/0xf0 ? io_msg_ring+0x3cb/0x9f0 kasan_check_range+0x140/0x190 io_msg_ring+0x3cb/0x9f0 ? io_msg_ring_prep+0x300/0x300 io_issue_sqe+0x698/0xca0 io_submit_sqes+0x92f/0x1c30 __do_sys_io_uring_enter+0xae4/0x24b0 .... RIP: 0033:0x7f2eaf8f8289 RSP: 002b:00007fff40939718 EFLAGS: 00000246 ORIG_RAX: 00000000000001aa RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f2eaf8f8289 RDX: 0000000000000000 RSI: 0000000000006f71 RDI: 0000000000000004 RBP: 00007fff409397a0 R08: 0000000000000000 R09: 0000000000000039 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000004006d0 R13: 00007fff40939880 R14: 0000000000000000 R15: 0000000000000000 </TASK> Kernel panic - not syncing: panic_on_warn set ... We don't have a NULL check on file_ptr in io_msg_send_fd() function, so when file_ptr is NUL src_file is also NULL and get_file() dereferences a NULL pointer and leads to above crash. Add a NULL check to fix this issue.Show less