NO_MERGE This is an example PR with an upstream commit checker github action #323
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
jira VULN-164 cve CVE-2022-3565 commit-author Duoming Zhou <[email protected]> commit 2568a7e The l1oip_cleanup() traverses the l1oip_ilist and calls release_card() to cleanup module and stack. However, release_card() calls del_timer() to delete the timers such as keep_tl and timeout_tl. If the timer handler is running, the del_timer() will not stop it and result in UAF bugs. One of the processes is shown below: (cleanup routine) | (timer handler) release_card() | l1oip_timeout() ... | del_timer() | ... ... | kfree(hc) //FREE | | hc->timeout_on = 0 //USE Fix by calling del_timer_sync() in release_card(), which makes sure the timer handlers have finished before the resources, such as l1oip and so on, have been deallocated. What's more, the hc->workq and hc->socket_thread can kick those timers right back in. We add a bool flag to show if card is released. Then, check this flag in hc->workq and hc->socket_thread. Fixes: 3712b42 ("Add layer1 over IP support") Signed-off-by: Duoming Zhou <[email protected]> Reviewed-by: Leon Romanovsky <[email protected]> Signed-off-by: David S. Miller <[email protected]> (cherry picked from commit 2568a7e) Signed-off-by: Pratham Patel <[email protected]>
jira VULN-409 cve CVE-2023-39198 commit-author Wander Lairson Costa <[email protected]> commit c611589 qxl_mode_dumb_create() dereferences the qobj returned by qxl_gem_object_create_with_handle(), but the handle is the only one holding a reference to it. A potential attacker could guess the returned handle value and closes it between the return of qxl_gem_object_create_with_handle() and the qobj usage, triggering a use-after-free scenario. Reproducer: int dri_fd =-1; struct drm_mode_create_dumb arg = {0}; void gem_close(int handle); void* trigger(void* ptr) { int ret; arg.width = arg.height = 0x20; arg.bpp = 32; ret = ioctl(dri_fd, DRM_IOCTL_MODE_CREATE_DUMB, &arg); if(ret) { perror("[*] DRM_IOCTL_MODE_CREATE_DUMB Failed"); exit(-1); } gem_close(arg.handle); while(1) { struct drm_mode_create_dumb args = {0}; args.width = args.height = 0x20; args.bpp = 32; ret = ioctl(dri_fd, DRM_IOCTL_MODE_CREATE_DUMB, &args); if (ret) { perror("[*] DRM_IOCTL_MODE_CREATE_DUMB Failed"); exit(-1); } printf("[*] DRM_IOCTL_MODE_CREATE_DUMB created, %d\n", args.handle); gem_close(args.handle); } return NULL; } void gem_close(int handle) { struct drm_gem_close args; args.handle = handle; int ret = ioctl(dri_fd, DRM_IOCTL_GEM_CLOSE, &args); // gem close handle if (!ret) printf("gem close handle %d\n", args.handle); } int main(void) { dri_fd= open("/dev/dri/card0", O_RDWR); printf("fd:%d\n", dri_fd); if(dri_fd == -1) return -1; pthread_t tid1; if(pthread_create(&tid1,NULL,trigger,NULL)){ perror("[*] thread_create tid1\n"); return -1; } while (1) { gem_close(arg.handle); } return 0; } This is a KASAN report: ================================================================== BUG: KASAN: slab-use-after-free in qxl_mode_dumb_create+0x3c2/0x400 linux/drivers/gpu/drm/qxl/qxl_dumb.c:69 Write of size 1 at addr ffff88801136c240 by task poc/515 CPU: 1 PID: 515 Comm: poc Not tainted 6.3.0 #3 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.0-debian-1.16.0-4 04/01/2014 Call Trace: <TASK> __dump_stack linux/lib/dump_stack.c:88 dump_stack_lvl+0x48/0x70 linux/lib/dump_stack.c:106 print_address_description linux/mm/kasan/report.c:319 print_report+0xd2/0x660 linux/mm/kasan/report.c:430 kasan_report+0xd2/0x110 linux/mm/kasan/report.c:536 __asan_report_store1_noabort+0x17/0x30 linux/mm/kasan/report_generic.c:383 qxl_mode_dumb_create+0x3c2/0x400 linux/drivers/gpu/drm/qxl/qxl_dumb.c:69 drm_mode_create_dumb linux/drivers/gpu/drm/drm_dumb_buffers.c:96 drm_mode_create_dumb_ioctl+0x1f5/0x2d0 linux/drivers/gpu/drm/drm_dumb_buffers.c:102 drm_ioctl_kernel+0x21d/0x430 linux/drivers/gpu/drm/drm_ioctl.c:788 drm_ioctl+0x56f/0xcc0 linux/drivers/gpu/drm/drm_ioctl.c:891 vfs_ioctl linux/fs/ioctl.c:51 __do_sys_ioctl linux/fs/ioctl.c:870 __se_sys_ioctl linux/fs/ioctl.c:856 __x64_sys_ioctl+0x13d/0x1c0 linux/fs/ioctl.c:856 do_syscall_x64 linux/arch/x86/entry/common.c:50 do_syscall_64+0x5b/0x90 linux/arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x72/0xdc linux/arch/x86/entry/entry_64.S:120 RIP: 0033:0x7ff5004ff5f7 Code: 00 00 00 48 8b 05 99 c8 0d 00 64 c7 00 26 00 00 00 48 c7 c0 ff ff ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 b8 10 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 69 c8 0d 00 f7 d8 64 89 01 48 RSP: 002b:00007ff500408ea8 EFLAGS: 00000286 ORIG_RAX: 0000000000000010 RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007ff5004ff5f7 RDX: 00007ff500408ec0 RSI: 00000000c02064b2 RDI: 0000000000000003 RBP: 00007ff500408ef0 R08: 0000000000000000 R09: 000000000000002a R10: 0000000000000000 R11: 0000000000000286 R12: 00007fff1c6cdafe R13: 00007fff1c6cdaff R14: 00007ff500408fc0 R15: 0000000000802000 </TASK> Allocated by task 515: kasan_save_stack+0x38/0x70 linux/mm/kasan/common.c:45 kasan_set_track+0x25/0x40 linux/mm/kasan/common.c:52 kasan_save_alloc_info+0x1e/0x40 linux/mm/kasan/generic.c:510 ____kasan_kmalloc linux/mm/kasan/common.c:374 __kasan_kmalloc+0xc3/0xd0 linux/mm/kasan/common.c:383 kasan_kmalloc linux/./include/linux/kasan.h:196 kmalloc_trace+0x48/0xc0 linux/mm/slab_common.c:1066 kmalloc linux/./include/linux/slab.h:580 kzalloc linux/./include/linux/slab.h:720 qxl_bo_create+0x11a/0x610 linux/drivers/gpu/drm/qxl/qxl_object.c:124 qxl_gem_object_create+0xd9/0x360 linux/drivers/gpu/drm/qxl/qxl_gem.c:58 qxl_gem_object_create_with_handle+0xa1/0x180 linux/drivers/gpu/drm/qxl/qxl_gem.c:89 qxl_mode_dumb_create+0x1cd/0x400 linux/drivers/gpu/drm/qxl/qxl_dumb.c:63 drm_mode_create_dumb linux/drivers/gpu/drm/drm_dumb_buffers.c:96 drm_mode_create_dumb_ioctl+0x1f5/0x2d0 linux/drivers/gpu/drm/drm_dumb_buffers.c:102 drm_ioctl_kernel+0x21d/0x430 linux/drivers/gpu/drm/drm_ioctl.c:788 drm_ioctl+0x56f/0xcc0 linux/drivers/gpu/drm/drm_ioctl.c:891 vfs_ioctl linux/fs/ioctl.c:51 __do_sys_ioctl linux/fs/ioctl.c:870 __se_sys_ioctl linux/fs/ioctl.c:856 __x64_sys_ioctl+0x13d/0x1c0 linux/fs/ioctl.c:856 do_syscall_x64 linux/arch/x86/entry/common.c:50 do_syscall_64+0x5b/0x90 linux/arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x72/0xdc linux/arch/x86/entry/entry_64.S:120 Freed by task 515: kasan_save_stack+0x38/0x70 linux/mm/kasan/common.c:45 kasan_set_track+0x25/0x40 linux/mm/kasan/common.c:52 kasan_save_free_info+0x2e/0x60 linux/mm/kasan/generic.c:521 ____kasan_slab_free linux/mm/kasan/common.c:236 ____kasan_slab_free+0x180/0x1f0 linux/mm/kasan/common.c:200 __kasan_slab_free+0x12/0x30 linux/mm/kasan/common.c:244 kasan_slab_free linux/./include/linux/kasan.h:162 slab_free_hook linux/mm/slub.c:1781 slab_free_freelist_hook+0xd2/0x1a0 linux/mm/slub.c:1807 slab_free linux/mm/slub.c:3787 __kmem_cache_free+0x196/0x2d0 linux/mm/slub.c:3800 kfree+0x78/0x120 linux/mm/slab_common.c:1019 qxl_ttm_bo_destroy+0x140/0x1a0 linux/drivers/gpu/drm/qxl/qxl_object.c:49 ttm_bo_release+0x678/0xa30 linux/drivers/gpu/drm/ttm/ttm_bo.c:381 kref_put linux/./include/linux/kref.h:65 ttm_bo_put+0x50/0x80 linux/drivers/gpu/drm/ttm/ttm_bo.c:393 qxl_gem_object_free+0x3e/0x60 linux/drivers/gpu/drm/qxl/qxl_gem.c:42 drm_gem_object_free+0x5c/0x90 linux/drivers/gpu/drm/drm_gem.c:974 kref_put linux/./include/linux/kref.h:65 __drm_gem_object_put linux/./include/drm/drm_gem.h:431 drm_gem_object_put linux/./include/drm/drm_gem.h:444 qxl_gem_object_create_with_handle+0x151/0x180 linux/drivers/gpu/drm/qxl/qxl_gem.c:100 qxl_mode_dumb_create+0x1cd/0x400 linux/drivers/gpu/drm/qxl/qxl_dumb.c:63 drm_mode_create_dumb linux/drivers/gpu/drm/drm_dumb_buffers.c:96 drm_mode_create_dumb_ioctl+0x1f5/0x2d0 linux/drivers/gpu/drm/drm_dumb_buffers.c:102 drm_ioctl_kernel+0x21d/0x430 linux/drivers/gpu/drm/drm_ioctl.c:788 drm_ioctl+0x56f/0xcc0 linux/drivers/gpu/drm/drm_ioctl.c:891 vfs_ioctl linux/fs/ioctl.c:51 __do_sys_ioctl linux/fs/ioctl.c:870 __se_sys_ioctl linux/fs/ioctl.c:856 __x64_sys_ioctl+0x13d/0x1c0 linux/fs/ioctl.c:856 do_syscall_x64 linux/arch/x86/entry/common.c:50 do_syscall_64+0x5b/0x90 linux/arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x72/0xdc linux/arch/x86/entry/entry_64.S:120 The buggy address belongs to the object at ffff88801136c000 which belongs to the cache kmalloc-1k of size 1024 The buggy address is located 576 bytes inside of freed 1024-byte region [ffff88801136c000, ffff88801136c400) The buggy address belongs to the physical page: page:0000000089fc329b refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x11368 head:0000000089fc329b order:3 entire_mapcount:0 nr_pages_mapped:0 pincount:0 flags: 0xfffffc0010200(slab|head|node=0|zone=1|lastcpupid=0x1fffff) raw: 000fffffc0010200 ffff888007841dc0 dead000000000122 0000000000000000 raw: 0000000000000000 0000000080100010 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88801136c100: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801136c180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88801136c200: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88801136c280: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88801136c300: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== Disabling lock debugging due to kernel taint Instead of returning a weak reference to the qxl_bo object, return the created drm_gem_object and let the caller decrement the reference count when it no longer needs it. As a convenience, if the caller is not interested in the gobj object, it can pass NULL to the parameter and the reference counting is descremented internally. The bug and the reproducer were originally found by the Zero Day Initiative project (ZDI-CAN-20940). Link: https://www.zerodayinitiative.com/ Signed-off-by: Wander Lairson Costa <[email protected]> Cc: [email protected] Reviewed-by: Dave Airlie <[email protected]> Signed-off-by: Dave Airlie <[email protected]> Link: https://patchwork.freedesktop.org/patch/msgid/[email protected] (cherry picked from commit c611589) Signed-off-by: Pratham Patel <[email protected]>
jira VULN-473 cve CVE-2023-51780 commit-author Hyunwoo Kim <[email protected]> commit 24e90b9 Because do_vcc_ioctl() accesses sk->sk_receive_queue without holding a sk->sk_receive_queue.lock, it can cause a race with vcc_recvmsg(). A use-after-free for skb occurs with the following flow. ``` do_vcc_ioctl() -> skb_peek() vcc_recvmsg() -> skb_recv_datagram() -> skb_free_datagram() ``` Add sk->sk_receive_queue.lock to do_vcc_ioctl() to fix this issue. Fixes: 1da177e ("Linux-2.6.12-rc2") Signed-off-by: Hyunwoo Kim <[email protected]> Link: https://lore.kernel.org/r/20231209094210.GA403126@v4bel-B760M-AORUS-ELITE-AX Signed-off-by: Paolo Abeni <[email protected]> (cherry picked from commit 24e90b9) Signed-off-by: Pratham Patel <[email protected]>
jira VULN-465 cve CVE-2023-51779 commit-author Hyunwoo Kim <[email protected]> commit 2e07e83 upstream-diff We are missing f4b41f0 ("net: remove noblock parameter from skb_recv_datagram()") commit. The patch is clean otherwise. This can cause a race with bt_sock_ioctl() because bt_sock_recvmsg() gets the skb from sk->sk_receive_queue and then frees it without holding lock_sock. A use-after-free for a skb occurs with the following flow. ``` bt_sock_recvmsg() -> skb_recv_datagram() -> skb_free_datagram() bt_sock_ioctl() -> skb_peek() ``` Add lock_sock to bt_sock_recvmsg() to fix this issue. Cc: [email protected] Fixes: 1da177e ("Linux-2.6.12-rc2") Signed-off-by: Hyunwoo Kim <[email protected]> Signed-off-by: Luiz Augusto von Dentz <[email protected]> (cherry picked from commit 2e07e83) Signed-off-by: Pratham Patel <[email protected]>
jira VULN-329 cve CVE-2023-28464 commit-author ZhengHan Wang <[email protected]> commit a85fb91 syzbot reports a slab use-after-free in hci_conn_hash_flush [1]. After releasing an object using hci_conn_del_sysfs in the hci_conn_cleanup function, releasing the same object again using the hci_dev_put and hci_conn_put functions causes a double free. Here's a simplified flow: hci_conn_del_sysfs: hci_dev_put put_device kobject_put kref_put kobject_release kobject_cleanup kfree_const kfree(name) hci_dev_put: ... kfree(name) hci_conn_put: put_device ... kfree(name) This patch drop the hci_dev_put and hci_conn_put function call in hci_conn_cleanup function, because the object is freed in hci_conn_del_sysfs function. This patch also fixes the refcounting in hci_conn_add_sysfs() and hci_conn_del_sysfs() to take into account device_add() failures. This fixes CVE-2023-28464. Link: https://syzkaller.appspot.com/bug?id=1bb51491ca5df96a5f724899d1dbb87afda61419 [1] Signed-off-by: ZhengHan Wang <[email protected]> Co-developed-by: Luiz Augusto von Dentz <[email protected]> Signed-off-by: Luiz Augusto von Dentz <[email protected]> (cherry picked from commit a85fb91) Signed-off-by: Pratham Patel <[email protected]>
jira VULN-679 cve CVE-2023-6622 commit-author Pablo Neira Ayuso <[email protected]> commit 3701cd3 If dynset expressions provided by userspace is larger than the declared set expressions, then bail out. Fixes: 48b0ae0 ("netfilter: nftables: netlink support for several set element expressions") Reported-by: Xingyuan Mo <[email protected]> Signed-off-by: Pablo Neira Ayuso <[email protected]> (cherry picked from commit 3701cd3) Signed-off-by: Pratham Patel <[email protected]>
jira VULN-703 cve CVE-2023-6932 commit-author Zhengchao Shao <[email protected]> commit e2b706c When I perform the following test operations: 1.ip link add br0 type bridge 2.brctl addif br0 eth0 3.ip addr add 239.0.0.1/32 dev eth0 4.ip addr add 239.0.0.1/32 dev br0 5.ip addr add 224.0.0.1/32 dev br0 6.while ((1)) do ifconfig br0 up ifconfig br0 down done 7.send IGMPv2 query packets to port eth0 continuously. For example, ./mausezahn ethX -c 0 "01 00 5e 00 00 01 00 72 19 88 aa 02 08 00 45 00 00 1c 00 01 00 00 01 02 0e 7f c0 a8 0a b7 e0 00 00 01 11 64 ee 9b 00 00 00 00" The preceding tests may trigger the refcnt uaf issue of the mc list. The stack is as follows: refcount_t: addition on 0; use-after-free. WARNING: CPU: 21 PID: 144 at lib/refcount.c:25 refcount_warn_saturate (lib/refcount.c:25) CPU: 21 PID: 144 Comm: ksoftirqd/21 Kdump: loaded Not tainted 6.7.0-rc1-next-20231117-dirty #80 Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011 RIP: 0010:refcount_warn_saturate (lib/refcount.c:25) RSP: 0018:ffffb68f00657910 EFLAGS: 00010286 RAX: 0000000000000000 RBX: ffff8a00c3bf96c0 RCX: ffff8a07b6160908 RDX: 00000000ffffffd8 RSI: 0000000000000027 RDI: ffff8a07b6160900 RBP: ffff8a00cba36862 R08: 0000000000000000 R09: 00000000ffff7fff R10: ffffb68f006577c0 R11: ffffffffb0fdcdc8 R12: ffff8a00c3bf9680 R13: ffff8a00c3bf96f0 R14: 0000000000000000 R15: ffff8a00d8766e00 FS: 0000000000000000(0000) GS:ffff8a07b6140000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000055f10b520b28 CR3: 000000039741a000 CR4: 00000000000006f0 Call Trace: <TASK> igmp_heard_query (net/ipv4/igmp.c:1068) igmp_rcv (net/ipv4/igmp.c:1132) ip_protocol_deliver_rcu (net/ipv4/ip_input.c:205) ip_local_deliver_finish (net/ipv4/ip_input.c:234) __netif_receive_skb_one_core (net/core/dev.c:5529) netif_receive_skb_internal (net/core/dev.c:5729) netif_receive_skb (net/core/dev.c:5788) br_handle_frame_finish (net/bridge/br_input.c:216) nf_hook_bridge_pre (net/bridge/br_input.c:294) __netif_receive_skb_core (net/core/dev.c:5423) __netif_receive_skb_list_core (net/core/dev.c:5606) __netif_receive_skb_list (net/core/dev.c:5674) netif_receive_skb_list_internal (net/core/dev.c:5764) napi_gro_receive (net/core/gro.c:609) e1000_clean_rx_irq (drivers/net/ethernet/intel/e1000/e1000_main.c:4467) e1000_clean (drivers/net/ethernet/intel/e1000/e1000_main.c:3805) __napi_poll (net/core/dev.c:6533) net_rx_action (net/core/dev.c:6735) __do_softirq (kernel/softirq.c:554) run_ksoftirqd (kernel/softirq.c:913) smpboot_thread_fn (kernel/smpboot.c:164) kthread (kernel/kthread.c:388) ret_from_fork (arch/x86/kernel/process.c:153) ret_from_fork_asm (arch/x86/entry/entry_64.S:250) </TASK> The root causes are as follows: Thread A Thread B ... netif_receive_skb br_dev_stop ... br_multicast_leave_snoopers ... __ip_mc_dec_group ... __igmp_group_dropped igmp_rcv igmp_stop_timer igmp_heard_query //ref = 1 ip_ma_put igmp_mod_timer refcount_dec_and_test igmp_start_timer //ref = 0 ... refcount_inc //ref increases from 0 When the device receives an IGMPv2 Query message, it starts the timer immediately, regardless of whether the device is running. If the device is down and has left the multicast group, it will cause the mc list refcount uaf issue. Fixes: 1da177e ("Linux-2.6.12-rc2") Signed-off-by: Zhengchao Shao <[email protected]> Reviewed-by: Eric Dumazet <[email protected]> Reviewed-by: Hangbin Liu <[email protected]> Signed-off-by: David S. Miller <[email protected]> (cherry picked from commit e2b706c) Signed-off-by: Pratham Patel <[email protected]>
jira VULN-20 cve CVE-2019-15505 commit-author Sean Young <[email protected]> commit 0c4df39 Ensure we do not access the buffer beyond the end if no 0xff byte is encountered. Reported-by: [email protected] Signed-off-by: Sean Young <[email protected]> Reviewed-by: Kees Cook <[email protected]> Signed-off-by: Mauro Carvalho Chehab <[email protected]> (cherry picked from commit 0c4df39) Signed-off-by: Pratham Patel <[email protected]>
jira VULN-XXXX cve CVE-2025-1234 commit 1234567890abcde1234567890abcde1234567890 This isn't a real commit Do i dont have to say anything here
This github actions checks the PR commits for references to upstream linux commits (lines starting with "commit <hash>") and does two things: 1. Checks that this hash exists in the upstream linux kernel history 2. Checks if there are any Fixes: references for the referenced commit in the upstream linux kernel history If either of those are found to be true a comment is added to the PR with the pertinent information
|
PlaidCat
reviewed
Jun 6, 2025
| - name: Clone Linux Kernel | ||
| run: | | ||
| echo "Cloning Linux kernel repository (bare clone, single branch, no blobs) into 'linux' directory..." | ||
| git clone --bare --filter=blob:none --single-branch https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git linux |
There was a problem hiding this comment.
Any reason we just can't use the kernel-mainline branch its updated daily
There was a problem hiding this comment.
It could. If you look below you'll see that the script doesn't actually checkout the kernel-src-tree repo. It uses the github api to get the commits in the PR. But yea, maybe actually checking out kernel-src-tree with its kernel-mainline branch included makes sense.
There was a problem hiding this comment.
Initially the script used the github api to check the upstream kernel commits too, but that was taking forever
|
closing this. its served its purpose |
|
This is amazing! This could help us improve the quality of our tree better than RedHat's. |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
It has occurred to me that I don't always check my backports to see if there are upstream fixes. I also don't always remember to check other peoples PRs to see if there are upstream fixes for the commits they are backporting. As such, with the help of AI, I've whipped up this github action that checks PR commits for two things IFF they reference an upstream commit in the commit message (if a line like this exists: "commit "):
Does the referenced commit exist in the upstream kernel commit history
Are there any references to Fixes: for the referenced commit in the upstream kernel commit history
If the github action finds either of those things, it makes a comment on the PR with the pertinent information. I decided not to make the github action a pass/fail check as I think we don't necessarily always want to enforce that all upstream fixes be pulled into the PR. So this is just an information comment that the PR author and reviewers will get to look at.
This PR is actually a copy of this PR #314 that I know has a couple of backports with upstream fixes available. I have also added another commit that references a bogus hash just so you can see the output.
I do not intend for this PR to be merged. If reviewers like this upstream commit checker (or at least the idea of it) I can make an actual PR for the checker and we can do a full review there. See what you think.