CVE-2023-52621

Published Mar 26, 2024

Last updated 8 months ago

Overview

Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Check rcu_read_lock_trace_held() before calling bpf map helpers These three bpf_map_{lookup,update,delete}_elem() helpers are also available for sleepable bpf program, so add the corresponding lock assertion for sleepable bpf program, otherwise the following warning will be reported when a sleepable bpf program manipulates bpf map under interpreter mode (aka bpf_jit_enable=0): WARNING: CPU: 3 PID: 4985 at kernel/bpf/helpers.c:40 ...... CPU: 3 PID: 4985 Comm: test_progs Not tainted 6.6.0+ #2 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) ...... RIP: 0010:bpf_map_lookup_elem+0x54/0x60 ...... Call Trace: <TASK> ? __warn+0xa5/0x240 ? bpf_map_lookup_elem+0x54/0x60 ? report_bug+0x1ba/0x1f0 ? handle_bug+0x40/0x80 ? exc_invalid_op+0x18/0x50 ? asm_exc_invalid_op+0x1b/0x20 ? __pfx_bpf_map_lookup_elem+0x10/0x10 ? rcu_lockdep_current_cpu_online+0x65/0xb0 ? rcu_is_watching+0x23/0x50 ? bpf_map_lookup_elem+0x54/0x60 ? __pfx_bpf_map_lookup_elem+0x10/0x10 ___bpf_prog_run+0x513/0x3b70 __bpf_prog_run32+0x9d/0xd0 ? __bpf_prog_enter_sleepable_recur+0xad/0x120 ? __bpf_prog_enter_sleepable_recur+0x3e/0x120 bpf_trampoline_6442580665+0x4d/0x1000 __x64_sys_getpgid+0x5/0x30 ? do_syscall_64+0x36/0xb0 entry_SYSCALL_64_after_hwframe+0x6e/0x76 </TASK>
Source
416baaa9-dc9f-4396-8d5f-8c081fb06d67
NVD status
Analyzed
Products
debian_linux, linux_kernel

Risk scores

CVSS 3.1

Type
Primary
Base score
7.8
Impact score
5.9
Exploitability score
1.8
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Severity
HIGH

Weaknesses

nvd@nist.gov
CWE-617

Social media

Hype score
Not currently trending

Configurations

  1. In the Linux kernel, the following vulnerability has been resolved: ipv6: account for fraggap on the paged allocation path In __ip6_append_data(), when the paged-allocation branch is taken (MSG_MORE / NETIF_F_SG / large fraglen), alloclen and pagedlen are computed as alloclen = fragheaderlen + transhdrlen; pagedlen = datalen - transhdrlen; datalen already includes fraggap (datalen = length + fraggap). When fraggap is non-zero, this is not the first skb and transhdrlen is zero. The fraggap bytes carried over from the previous skb are copied just past the fragment headers in the new skb's linear area. The linear area is therefore undersized by fraggap bytes while pagedlen is overstated by the same amount, and the copy writes past skb->end into the trailing skb_shared_info. An unprivileged user can trigger this via a UDPv6 socket using MSG_MORE together with MSG_SPLICE_PAGES. The bad accounting was introduced by commit 773ba4fe9104 ("ipv6: avoid partial copy for zc"). Before commit ce650a166335 ("udp6: Fix __ip6_append_data()'s handling of MSG_SPLICE_PAGES"), the negative copy value caused -EINVAL to be returned. That later commit allowed MSG_SPLICE_PAGES to proceed in this case, making the corruption triggerable. The non-paged branch sets alloclen to fraglen, which already accounts for fraggap because datalen does. Bring the paged branch in line by adding fraggap to alloclen and subtracting it from pagedlen. After this adjustment, copy no longer collapses to -fraggap on the paged path, so remove the stale comment describing that old arithmetic. Since a negative copy is no longer expected for a valid MSG_SPLICE_PAGES case, remove the MSG_SPLICE_PAGES exception from the negative copy check.CVE-2026-53362