CVE-2024-42073: linux Use After Free

Vulnerability summary

CVE-2024-42073 is a medium (CVSS 5.5) Use After Free vulnerability in linux. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 11.7% of scored vulnerabilities.

Timeline

1. 29-07-2024
   PublishedVulnerability first disclosed.
2. 11-05-2026
   Last modifiedVulnerability information updated.

Description

In the Linux kernel, the following vulnerability has been resolved: mlxsw: spectrum_buffers: Fix memory corruptions on Spectrum-4 systems The following two shared buffer operations make use of the Shared Buffer Status Register (SBSR): # devlink sb occupancy snapshot pci/0000:01:00.0 # devlink sb occupancy clearmax pci/0000:01:00.0 The register has two masks of 256 bits to denote on which ingress / egress ports the register should operate on. Spectrum-4 has more than 256 ports, so the register was extended by cited commit with a new 'port_page' field. However, when filling the register's payload, the driver specifies the ports as absolute numbers and not relative to the first port of the port page, resulting in memory corruptions [1]. Fix by specifying the ports relative to the first port of the port page. [1] BUG: KASAN: slab-use-after-free in mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0 Read of size 1 at addr ffff8881068cb00f by task devlink/1566 [...] Call Trace: <TASK> dump_stack_lvl+0xc6/0x120 print_report+0xce/0x670 kasan_report+0xd7/0x110 mlxsw_sp_sb_occ_snapshot+0xb6d/0xbc0 mlxsw_devlink_sb_occ_snapshot+0x75/0xb0 devlink_nl_sb_occ_snapshot_doit+0x1f9/0x2a0 genl_family_rcv_msg_doit+0x20c/0x300 genl_rcv_msg+0x567/0x800 netlink_rcv_skb+0x170/0x450 genl_rcv+0x2d/0x40 netlink_unicast+0x547/0x830 netlink_sendmsg+0x8d4/0xdb0 __sys_sendto+0x49b/0x510 __x64_sys_sendto+0xe5/0x1c0 do_syscall_64+0xc1/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f [...] Allocated by task 1: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 __kasan_kmalloc+0x8f/0xa0 copy_verifier_state+0xbc2/0xfb0 do_check_common+0x2c51/0xc7e0 bpf_check+0x5107/0x9960 bpf_prog_load+0xf0e/0x2690 __sys_bpf+0x1a61/0x49d0 __x64_sys_bpf+0x7d/0xc0 do_syscall_64+0xc1/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f Freed by task 1: kasan_save_stack+0x33/0x60 kasan_save_track+0x14/0x30 kasan_save_free_info+0x3b/0x60 poison_slab_object+0x109/0x170 __kasan_slab_free+0x14/0x30 kfree+0xca/0x2b0 free_verifier_state+0xce/0x270 do_check_common+0x4828/0xc7e0 bpf_check+0x5107/0x9960 bpf_prog_load+0xf0e/0x2690 __sys_bpf+0x1a61/0x49d0 __x64_sys_bpf+0x7d/0xc0 do_syscall_64+0xc1/0x1d0 entry_SYSCALL_64_after_hwframe+0x77/0x7f

• CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.