Description

In the Linux kernel, the following vulnerability has been resolved: dccp: fix dccp_v4_err()/dccp_v6_err() again dh->dccph_x is the 9th byte (offset 8) in "struct dccp_hdr", not in the "byte 7" as Jann claimed. We need to make sure the ICMP messages are big enough, using more standard ways (no more assumptions). syzbot reported: BUG: KMSAN: uninit-value in pskb_may_pull_reason include/linux/skbuff.h:2667 [inline] BUG: KMSAN: uninit-value in pskb_may_pull include/linux/skbuff.h:2681 [inline] BUG: KMSAN: uninit-value in dccp_v6_err+0x426/0x1aa0 net/dccp/ipv6.c:94 pskb_may_pull_reason include/linux/skbuff.h:2667 [inline] pskb_may_pull include/linux/skbuff.h:2681 [inline] dccp_v6_err+0x426/0x1aa0 net/dccp/ipv6.c:94 icmpv6_notify+0x4c7/0x880 net/ipv6/icmp.c:867 icmpv6_rcv+0x19d5/0x30d0 ip6_protocol_deliver_rcu+0xda6/0x2a60 net/ipv6/ip6_input.c:438 ip6_input_finish net/ipv6/ip6_input.c:483 [inline] NF_HOOK include/linux/netfilter.h:304 [inline] ip6_input+0x15d/0x430 net/ipv6/ip6_input.c:492 ip6_mc_input+0xa7e/0xc80 net/ipv6/ip6_input.c:586 dst_input include/net/dst.h:468 [inline] ip6_rcv_finish+0x5db/0x870 net/ipv6/ip6_input.c:79 NF_HOOK include/linux/netfilter.h:304 [inline] ipv6_rcv+0xda/0x390 net/ipv6/ip6_input.c:310 __netif_receive_skb_one_core net/core/dev.c:5523 [inline] __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5637 netif_receive_skb_internal net/core/dev.c:5723 [inline] netif_receive_skb+0x58/0x660 net/core/dev.c:5782 tun_rx_batched+0x83b/0x920 tun_get_user+0x564c/0x6940 drivers/net/tun.c:2002 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048 call_write_iter include/linux/fs.h:1985 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x8ef/0x15c0 fs/read_write.c:584 ksys_write+0x20f/0x4c0 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __x64_sys_write+0x93/0xd0 fs/read_write.c:646 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd Uninit was created at: slab_post_alloc_hook+0x12f/0xb70 mm/slab.h:767 slab_alloc_node mm/slub.c:3478 [inline] kmem_cache_alloc_node+0x577/0xa80 mm/slub.c:3523 kmalloc_reserve+0x13d/0x4a0 net/core/skbuff.c:559 __alloc_skb+0x318/0x740 net/core/skbuff.c:650 alloc_skb include/linux/skbuff.h:1286 [inline] alloc_skb_with_frags+0xc8/0xbd0 net/core/skbuff.c:6313 sock_alloc_send_pskb+0xa80/0xbf0 net/core/sock.c:2795 tun_alloc_skb drivers/net/tun.c:1531 [inline] tun_get_user+0x23cf/0x6940 drivers/net/tun.c:1846 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048 call_write_iter include/linux/fs.h:1985 [inline] new_sync_write fs/read_write.c:491 [inline] vfs_write+0x8ef/0x15c0 fs/read_write.c:584 ksys_write+0x20f/0x4c0 fs/read_write.c:637 __do_sys_write fs/read_write.c:649 [inline] __se_sys_write fs/read_write.c:646 [inline] __x64_sys_write+0x93/0xd0 fs/read_write.c:646 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd CPU: 0 PID: 4995 Comm: syz-executor153 Not tainted 6.6.0-rc1-syzkaller-00014-ga747acc0b752 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/04/2023

Severity

 

CVSS Version 3.x CVSS Version 2.0

CVSS 3.x Severity and Metrics:

NIST: NVD

Base Score:  N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

CVSS 2.0 Severity and Metrics:

NIST: NVD

Base Score: N/A

NVD assessment not yet provided.

NVD Analysts use publicly available information to associate vector strings and CVSS scores. We also display any CVSS information provided within the CVE List from the CNA.

Note: NVD Analysts have not published a CVSS score for this CVE at this time. NVD Analysts use publicly available information at the time of analysis to associate CVSS vector strings.

kernel.org https://git.kernel.org/stable/c/6af289746a636f71f4c0535a9801774118486c7a [No types assigned]

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

dccp: fix dccp_v4_err()/dccp_v6_err() again

dh->dccph_x is the 9th byte (offset 8) in "struct dccp_hdr",
not in the "byte 7" as Jann claimed.

We need to make sure the ICMP messages are big enough,
using more standard ways (no more assumptions).

syzbot reported:
BUG: KMSAN: uninit-value in pskb_may_pull_reason include/linux/skbuff.h:2667 [inline]
BUG: KMSAN: uninit-value in pskb_may_pull include/linux/skbuff.h:2681 [inline]
B

Linux https://git.kernel.org/stable/c/1512d8f45d3c5d0b5baa00bd8e600492fa569f40 [No types assigned]

Linux https://git.kernel.org/stable/c/26df9ab5de308caa1503d937533c56c35793018d [No types assigned]

Linux https://git.kernel.org/stable/c/4600beae416d754a3cedbb1ecea8181ec05073b6 [No types assigned]

Linux https://git.kernel.org/stable/c/60d73c62e3e4464f375758b6f2459c13d46465b6 [No types assigned]

Linux https://git.kernel.org/stable/c/62c218124fe58372e0e1f60d5b634d21c264b337 [No types assigned]

Linux https://git.kernel.org/stable/c/73be49248a04746096339a48a33fa2f03bd85969 [No types assigned]

Linux https://git.kernel.org/stable/c/a6f4d582e25d512c9b492670b6608436694357b3 [No types assigned]