CVE-2023-52778: mptcp: deal with large GSO size

Description

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

mptcp: deal with large GSO size

After the blamed commit below, the TCP sockets (and the MPTCP subflows)
can build egress packets larger than 64K. That exceeds the maximum DSS
data size, the length being misrepresent on the wire and the stream being
corrupted, as later observed on the receiver:

WARNING: CPU: 0 PID: 9696 at net/mptcp/protocol.c:705 __mptcp_move_skbs_from_subflow+0x2604/0x26e0
CPU: 0 PID: 9696 Comm: syz-executor.7 Not tainted 6.6.0-rc5-gcd8bdf563d46 #45
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.11.0-2.el7 04/01/2014
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.4'.
RIP: 0010:__mptcp_move_skbs_from_subflow+0x2604/0x26e0 net/mptcp/protocol.c:705
RSP: 0018:ffffc90000006e80 EFLAGS: 00010246
RAX: ffffffff83e9f674 RBX: ffff88802f45d870 RCX: ffff888102ad0000
netlink: 8 bytes leftover after parsing attributes in process `syz-executor.4'.
RDX: 0000000080000303 RSI: 0000000000013908 RDI: 0000000000003908
RBP: ffffc90000007110 R08: ffffffff83e9e078 R09: 1ffff1100e548c8a
R10: dffffc0000000000 R11: ffffed100e548c8b R12: 0000000000013908
R13: dffffc0000000000 R14: 0000000000003908 R15: 000000000031cf29
FS: 00007f239c47e700(0000) GS:ffff88811b200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f239c45cd78 CR3: 000000006a66c006 CR4: 0000000000770ef0
DR0: 0000000000000000 DR1: 0000...

Classification

CVE ID: CVE-2023-52778

Affected Products

Vendor: Linux

Product: Linux

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.05% (probability of being exploited)

EPSS Percentile: 17.83% (scored less or equal to compared to others)

EPSS Date: 2025-02-04 (when was this score calculated)

References

https://git.kernel.org/stable/c/70ff9b65a72885b3a2dfde6709da1f19b85fa696
https://git.kernel.org/stable/c/342b528c0e849bed9def76dadaa470d3af678e94
https://git.kernel.org/stable/c/57ced2eb77343a91d28f4a73675b05fe7b555def
https://git.kernel.org/stable/c/9fce92f050f448a0d1ddd9083ef967d9930f1e52

Timeline