CVE-2024-37356

CVE Details

Release Date:

2024-06-21

Description

In the Linux kernel, the following vulnerability has been resolved:\ntcp: Fix shift-out-of-bounds in dctcp_update_alpha().\nIn dctcp_update_alpha(), we use a module parameter dctcp_shift_g\nas follows:\nalpha -= min_not_zero(alpha, alpha >> dctcp_shift_g);\n...\ndelivered_ce <<= (10 - dctcp_shift_g);\nIt seems syzkaller started fuzzing module parameters and triggered\nshift-out-of-bounds [0] by setting 100 to dctcp_shift_g:\nmemcpy((void*)0x20000080,\n'/sys/module/tcp_dctcp/parameters/dctcp_shift_g\000', 47);\nres = syscall(__NR_openat, /*fd=*/0xffffffffffffff9cul, /*file=*/0x20000080ul,\n/*flags=*/2ul, /*mode=*/0ul);\nmemcpy((void*)0x20000000, '100\000', 4);\nsyscall(__NR_write, /*fd=*/r[0], /*val=*/0x20000000ul, /*len=*/4ul);\nLet's limit the max value of dctcp_shift_g by param_set_uint_minmax().\nWith this patch:\n# echo 10 > /sys/module/tcp_dctcp/parameters/dctcp_shift_g\n# cat /sys/module/tcp_dctcp/parameters/dctcp_shift_g\n10\n# echo 11 > /sys/module/tcp_dctcp/parameters/dctcp_shift_g\n-bash: echo: write error: Invalid argument\n[0]:\nUBSAN: shift-out-of-bounds in net/ipv4/tcp_dctcp.c:143:12\nshift exponent 100 is too large for 32-bit type 'u32' (aka 'unsigned int')\nCPU: 0 PID: 8083 Comm: syz-executor345 Not tainted 6.9.0-05151-g1b294a1f3561 #2\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS\n1.13.0-1ubuntu1.1 04/01/2014\nCall Trace:\n\n__dump_stack lib/dump_stack.c:88 [inline]\ndump_stack_lvl+0x201/0x300 lib/dump_stack.c:114\nubsan_epilogue lib/ubsan.c:231 [inline]\n__ubsan_handle_shift_out_of_bounds+0x346/0x3a0 lib/ubsan.c:468\ndctcp_update_alpha+0x540/0x570 net/ipv4/tcp_dctcp.c:143\ntcp_in_ack_event net/ipv4/tcp_input.c:3802 [inline]\ntcp_ack+0x17b1/0x3bc0 net/ipv4/tcp_input.c:3948\ntcp_rcv_state_process+0x57a/0x2290 net/ipv4/tcp_input.c:6711\ntcp_v4_do_rcv+0x764/0xc40 net/ipv4/tcp_ipv4.c:1937\nsk_backlog_rcv include/net/sock.h:1106 [inline]\n__release_sock+0x20f/0x350 net/core/sock.c:2983\nrelease_sock+0x61/0x1f0 net/core/sock.c:3549\nmptcp_subflow_shutdown+0x3d0/0x620 net/mptcp/protocol.c:2907\nmptcp_check_send_data_fin+0x225/0x410 net/mptcp/protocol.c:2976\n__mptcp_close+0x238/0xad0 net/mptcp/protocol.c:3072\nmptcp_close+0x2a/0x1a0 net/mptcp/protocol.c:3127\ninet_release+0x190/0x1f0 net/ipv4/af_inet.c:437\n__sock_release net/socket.c:659 [inline]\nsock_close+0xc0/0x240 net/socket.c:1421\n__fput+0x41b/0x890 fs/file_table.c:422\ntask_work_run+0x23b/0x300 kernel/task_work.c:180\nexit_task_work include/linux/task_work.h:38 [inline]\ndo_exit+0x9c8/0x2540 kernel/exit.c:878\ndo_group_exit+0x201/0x2b0 kernel/exit.c:1027\n__do_sys_exit_group kernel/exit.c:1038 [inline]\n__se_sys_exit_group kernel/exit.c:1036 [inline]\n__x64_sys_exit_group+0x3f/0x40 kernel/exit.c:1036\ndo_syscall_x64 arch/x86/entry/common.c:52 [inline]\ndo_syscall_64+0xe4/0x240 arch/x86/entry/common.c:83\nentry_SYSCALL_64_after_hwframe+0x67/0x6f\nRIP: 0033:0x7f6c2b5005b6\nCode: Unable to access opcode bytes at 0x7f6c2b50058c.\nRSP: 002b:00007ffe883eb948 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7\nRAX: ffffffffffffffda RBX: 00007f6c2b5862f0 RCX: 00007f6c2b5005b6\nRDX: 0000000000000001 RSI: 000000000000003c RDI: 0000000000000001\nRBP: 0000000000000001 R08: 00000000000000e7 R09: ffffffffffffffc0\nR10: 0000000000000006 R11: 0000000000000246 R12: 00007f6c2b5862f0\nR13: 0000000000000001 R14: 0000000000000000 R15: 0000000000000001\n

See more information about CVE-2024-37356 from MITRE CVE dictionary and NIST NVD

CVSS Scoring

NOTE: The following CVSS v3.1 metrics and score provided are preliminary and subject to review.

Base Score:	6.6	CVSS Vector:	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:H
Attack Vector:	Local network	Attack Complexity:	Low
Privileges Required:	Low	User Interaction:	None
Scope:	Unchanged	Confidentiality Impact:	Low
Integrity Impact:	Low	Availability Impact:	High

Errata information

Platform	Errata	Release Date
Oracle Linux version 7 (kernel-uek)	ELSA-2024-12581	2024-08-12
Oracle Linux version 7 (kernel-uek)	ELSA-2024-12611	2024-09-11
Oracle Linux version 7 (kernel-uek-container)	ELSA-2024-12585	2024-08-12
Oracle Linux version 8 (kernel-uek)	ELSA-2024-12581	2024-08-12
Oracle Linux version 8 (kernel-uek-container)	ELSA-2024-12584	2024-08-12
Oracle Linux version 9 (kernel)	ELSA-2024-5363	2024-08-14