CVE: CVE-2024-57882
Published: 2025-01-15
Description: In the Linux kernel, the following vulnerability has been resolved:

mptcp: fix TCP options overflow.

Syzbot reported the following splat:

Oops: general protection fault, probably for non-canonical address 0xdffffc[PII_REDACTED]: 0000 [#1] PREEMPT SMP KASAN PTI
KASAN: null-ptr-deref in range [0x[PII_REDACTED]000008-0x[PII_REDACTED]00000f]
CPU: 1 UID: 0 PID: 5836 Comm: sshd Not tainted 6.13.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/25/2024
RIP: 0010:_compound_head include/linux/page-flags.h:242 [inline]
RIP: 0010:put_page+0x23/0x260 include/linux/mm.h:1552
Code: 90 90 90 90 90 90 90 55 41 57 41 56 53 49 89 fe 48 bd 00 00 00 00 00 fc ff df e8 f8 5e 12 f8 49 8d 5e 08 48 89 d8 48 c1 e8 03 <80> 3c 28 00 74 08 48 89 df e8 8f c7 78 f8 48 8b 1b 48 89 de 48 83
RSP: 0000:ffffc90003916c90 EFLAGS: 00010202
RAX: [PII_REDACTED] RBX: [PII_REDACTED] RCX: ffff[PII_REDACTED]00
RDX: [PII_REDACTED] RSI: [PII_REDACTED] RDI: [PII_REDACTED]
RBP: dffffc[PII_REDACTED] R08: ffffffff898ca81d R09: 1ffff110054414ac
R10: dffffc[PII_REDACTED] R11: ffffed10054414ad R12: [PII_REDACTED]
R13: ffff88802a20a542 R14: [PII_REDACTED] R15: [PII_REDACTED]
FS:  00007f34f496e800(0000) GS:ffff8880b8700000(0000) knlGS:[PII_REDACTED]
CS:  0010 DS: 0000 ES: 0000 CR0: [PII_REDACTED]
CR2: 00007f9d6ec9ec28 CR3: 000000004d260000 CR4:[PII_REDACTED]3526f0
DR0: [PII_REDACTED] DR1: [PII_REDACTED] DR2: [PII_REDACTED]
DR3: [PII_REDACTED] DR6: 00000000fffe0ff0 DR7: [PII_REDACTED]
Call Trace:
 <TASK>
 skb_page_unref include/linux/skbuff_ref.h:43 [inline]
 __skb_frag_unref include/linux/skbuff_ref.h:56 [inline]
 skb_release_data+0x483/0x8a0 net/core/skbuff.c:1119
 skb_release_all net/core/skbuff.c:1190 [inline]
 __kfree_skb+0x55/0x70 net/core/skbuff.c:1204
 tcp_clean_rtx_queue net/ipv4/tcp_input.c:3436 [inline]
 tcp_ack+0x2442/0x6bc0 net/ipv4/tcp_input.c:4032
 tcp_rcv_state_process+0x8eb/0x44e0 net/ipv4/tcp_input.c:6805
 tcp_v4_do_rcv+0x77d/0xc70 net/ipv4/tcp_ipv4.c:1939
 tcp_v4_rcv+0x2dc0/0x37f0 net/ipv4/tcp_ipv4.c:2351
 ip_protocol_deliver_rcu+0x22e/0x440 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x341/0x5f0 net/ipv4/ip_input.c:233
 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
 NF_HOOK+0x3a4/0x450 include/linux/netfilter.h:314
 __netif_receive_skb_one_core net/core/dev.c:5672 [inline]
 __netif_receive_skb+0x2bf/0x650 net/core/dev.c:5785
 process_backlog+0x662/0x15b0 net/core/dev.c:6117
 __napi_poll+0xcb/0x490 net/core/dev.c:6883
 napi_poll net/core/dev.c:6952 [inline]
 net_rx_action+0x89b/0x1240 net/core/dev.c:7074
 handle_softirqs+0x2d4/0x9b0 kernel/softirq.c:561
 __do_softirq kernel/softirq.c:595 [inline]
 invoke_softirq kernel/softirq.c:435 [inline]
 __irq_exit_rcu+0xf7/0x220 kernel/softirq.c:662
 irq_exit_rcu+0x9/0x30 kernel/softirq.c:678
 instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1049 [inline]
 sysvec_apic_timer_interrupt+0x57/0xc0 arch/x86/kernel/apic/apic.c:1049
 asm_sysvec_apic_timer_interrupt+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0033:0x7f34f4519ad5
Code: 85 d2 74 0d 0f 10 02 48 8d 54 24 20 0f 11 44 24 20 64 8b 04 25 18 00 00 00 85 c0 75 27 41 b8 08 00 00 00 b8 0f 01 00 00 0f 05 <48> 3d 00 f0 ff ff 76 75 48 8b 15 24 73 0d 00 f7 d8 64 89 02 48 83
RSP: 002b:00007ffec5b32ce0 EFLAGS: 00000246
RAX: [PII_REDACTED] RBX:[PII_REDACTED]0668a0 RCX: 00007f34f4519ad5
RDX: 00007ffec5b32d00 RSI: [PII_REDACTED] RDI: 0000564f4bc6cae0
RBP: 0000564f4bc6b5a0 R08: [PII_REDACTED] R09: [PII_REDACTED]
R10: 00007ffec5b32de8 R11: [PII_REDACTED] R12: 0000564f48ea8aa4
R13: [PII_REDACTED] R14: 0000564f48ea93e8 R15: 00007ffec5b32d68
 </TASK>

Eric noted a probable shinfo->nr_frags corruption, which indeed
occurs.

The root cause is a buggy MPTCP option len computation in some
circumstances: the ADD_ADDR option should be mutually exclusive
with DSS since the blamed commit.

Still, mptcp_established_options_add_addr() tries to set the
relevant info in mptcp_out_options, if 
---truncated---
CVSS Score: 5.5 (MEDIUM)
CWE: CWE-476
References: https://git.kernel.org/stable/c/09ba95321a269019b5aa8e0c3bc80cf86d91fd18; https://git.kernel.org/stable/c/53fe947f67c93a5334aed3a7259fcc8a204f8bb6; https://git.kernel.org/stable/c/88b01048f286bb522f524ad99943ba86797d6514