In the Linux kernel, the following vulnerability has been resolved:

tcp: fix page frag corruption on page fault

Steffen reported a TCP stream corruption for HTTP requests served by the apache web-server using a cifs mount-point and memory mapping the relevant file.

The root cause is quite similar to the one addressed by commit 20eb4f29b602 ("net: fix sk_page_frag() recursion from memory reclaim"). Here the nested access to the task page frag is caused by a page fault on the (mmapped) user-space memory buffer coming from the cifs file.

The page fault handler performs an smb transaction on a different socket, inside the same process context. Since sk->sk_allaction for such socket does not prevent the usage for the task_frag, the nested allocation modify "under the hood" the page frag in use by the outer sendmsg call, corrupting the stream.

The overall relevant stack trace looks like the following:

httpd 78268 [001] 3461630.850950: probe:tcp_sendmsg_locked: ffffffff91461d91 tcp_sendmsg_locked+0x1 ffffffff91462b57 tcp_sendmsg+0x27 ffffffff9139814e sock_sendmsg+0x3e ffffffffc06dfe1d smb_send_kvec+0x28 [...] ffffffffc06cfaf8 cifs_readpages+0x213 ffffffff90e83c4b read_pages+0x6b ffffffff90e83f31 __do_page_cache_readahead+0x1c1 ffffffff90e79e98 filemap_fault+0x788 ffffffff90eb0458 __do_fault+0x38 ffffffff90eb5280 do_fault+0x1a0 ffffffff90eb7c84 __handle_mm_fault+0x4d4 f…

Affected: openEuler:20.03-LTS-SP4: kernel

The Linux Kernel, the operating system core itself. Security Fix(es): In the Linux kernel, the following vulnerability has been resolved: net: cdc_eem: fix tx fixup skb leak when usbnet transmit a skb, eem fixup it in eem_tx_fixup(), if skb_copy_expand() failed, it return NULL, usbnet_start_xmit() will have no chance to free original skb. fix it by free orginal skb in eem_tx_fixup() first, then check skb clone status, if failed, return NULL to usbnet.(CVE-2021-47236) 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.(CVE-2021-47254) In the Linux kernel, the following vulnerability has been resolved: netrom: Decrease sock refcount when sock timers expire Commit 63346650c1a9 ("netrom: switch to sock timer API") switched to use sock timer API. It replaces mod_timer() by sk_reset_timer(), and del_timer() by sk_stop_timer(). Function sk_reset_t…

kernel: Use After Free in unix_gc() which could result in a local privilege escalation kernel: use-after-free in RDMA listen() kernel: tcp: fix page frag corruption on page fault kernel: possible privileges escalation due to missing TLB flush kernel: remote stack overflow via kernel panic on systems using TIPC may lead to DoS kernel: missing check in ioctl allows kernel memory read/write kernel: failing usercopy allows for use-after-free exploitation

kernel: avoid cyclic entity chains due to malformed USB descriptors kernel: speculation on incompletely validated data on IBM Power9 kernel: integer overflow in k_ascii() in drivers/tty/vt/keyboard.c kernel: use-after-free in nouveau kernel module kernel: out-of-bounds read in bpf_skb_change_head() of filter.c due to a use-after-free kernel: joydev: zero size passed to joydev_handle_JSIOCSBTNMAP() kernel: reading /proc/sysvipc/shm does not scale with large shared memory segment counts kernel: out-of-bound Read in qrtr_endpoint_post in net/qrtr/qrtr.c kernel: crypto: ccp - fix resource leaks in ccp_run_aes_gcm_cmd() kernel: possible use-after-free in bluetooth module kernel: unaccounted ipc objects in Linux kernel lead to breaking memcg limits and DoS attacks kernel: DoS in ccp_run_aes_gcm_cmd() function kernel: sctp: Invalid chunks may be used to remotely remove existing associations kernel: lack of port sanity checking in natd and netfilter leads to exploit of OpenVPN clients kernel: stack information leak in infiniband RDMA kernel: possible leak or coruption of data residing on hugetlbfs kernel: security regression for CVE-2018-13405 kernel: fget: check that the fd still exists after getting a ref to it kernel: KVM: SVM: out-of-bounds read/write in sev_es_string_io kernel: Buffer overwrite in decode_nfs_fh function kernel: cgroup: Use open-time creds and namespace for migration perm checks kernel: Race condition in races in sk_peer_pid and sk_peer_cred accesses kernel: Lin…

Security update for the Linux Kernel

Affected: Ubuntu:Pro:14.04:LTS: linux, Ubuntu:Pro:14.04:LTS: linux-aws, Ubuntu:Pro:14.04:LTS: linux-azure, Ubuntu:Pro:14.04:LTS: linux-lts-xenial, Ubuntu:Pro:16.04:LTS: linux, Ubuntu:Pro:16.04:LTS: linux-aws, Ubuntu:Pro:16.04:LTS: linux-aws-hwe, Ubuntu:Pro:16.04:LTS: linux-azure, Ubuntu:Pro:16.04:LTS: linux-gcp, Ubuntu:Pro:16.04:LTS: linux-hwe and 111 more

In the Linux kernel, the following vulnerability has been resolved: tcp: fix page frag corruption on page fault Steffen reported a TCP stream corruption for HTTP requests served by the apache web-server using a cifs mount-point and memory mapping the relevant file. The root cause is quite similar to the one addressed by commit 20eb4f29b602 ("net: fix sk_page_frag() recursion from memory reclaim"). Here the nested access to the task page frag is caused by a page fault on the (mmapped) user-space memory buffer coming from the cifs file. The page fault handler performs an smb transaction on a different socket, inside the same process context. Since sk->sk_allaction for such socket does not prevent the usage for the task_frag, the nested allocation modify "under the hood" the page frag in use by the outer sendmsg call, corrupting the stream. The overall relevant stack trace looks like the following: httpd 78268 [001] 3461630.850950: probe:tcp_sendmsg_locked: ffffffff91461d91 tcp_sendmsg_locked+0x1 ffffffff91462b57 tcp_sendmsg+0x27 ffffffff9139814e sock_sendmsg+0x3e ffffffffc06dfe1d smb_send_kvec+0x28 [...] ffffffffc06cfaf8 cifs_readpages+0x213 ffffffff90e83c4b read_pages+0x6b ffffffff90e83f31 __do_page_cache_readahead+0x1c1 ffffffff90e79e98 filemap_fault+0x788 ffffffff90eb0458 __do_fault+0x38 ffffffff90eb5280 do_fault+0x1a0 ffffffff90eb7c84 __handle_mm_fault+0x4d4 fffffff…

Ein lokaler Angreifer kann mehrere Schwachstellen im Linux-Kernel ausnutzen, um einen Denial-of-Service-Zustand zu erzeugen oder unspezifische Angriffe durchzuführen.