CVE-2022-48925 in Linux
Summary
by MITRE • 08/22/2024
In the Linux kernel, the following vulnerability has been resolved:
RDMA/cma: Do not change route.addr.src_addr outside state checks
If the state is not idle then resolve_prepare_src() should immediately fail and no change to global state should happen. However, it unconditionally overwrites the src_addr trying to build a temporary any address.
For instance if the state is already RDMA_CM_LISTEN then this will corrupt the src_addr and would cause the test in cma_cancel_operation():
if (cma_any_addr(cma_src_addr(id_priv)) && !id_priv->cma_dev)
Which would manifest as this trace from syzkaller:
BUG: KASAN: use-after-free in __list_add_valid+0x93/0xa0 lib/list_debug.c:26 Read of size 8 at addr ffff8881546491e0 by task syz-executor.1/32204
CPU: 1 PID: 32204 Comm: syz-executor.1 Not tainted 5.12.0-rc8-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:79 [inline]
dump_stack+0x141/0x1d7 lib/dump_stack.c:120 print_address_description.constprop.0.cold+0x5b/0x2f8 mm/kasan/report.c:232 __kasan_report mm/kasan/report.c:399 [inline]
kasan_report.cold+0x7c/0xd8 mm/kasan/report.c:416 __list_add_valid+0x93/0xa0 lib/list_debug.c:26 __list_add include/linux/list.h:67 [inline]
list_add_tail include/linux/list.h:100 [inline]
cma_listen_on_all drivers/infiniband/core/cma.c:2557 [inline]
rdma_listen+0x787/0xe00 drivers/infiniband/core/cma.c:3751 ucma_listen+0x16a/0x210 drivers/infiniband/core/ucma.c:1102 ucma_write+0x259/0x350 drivers/infiniband/core/ucma.c:1732 vfs_write+0x28e/0xa30 fs/read_write.c:603 ksys_write+0x1ee/0x250 fs/read_write.c:658 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xae
This is indicating that an rdma_id_private was destroyed without doing cma_cancel_listens().
Instead of trying to re-use the src_addr memory to indirectly create an any address derived from the dst build one explicitly on the stack and bind to that as any other normal flow would do. rdma_bind_addr() will copy it over the src_addr once it knows the state is valid.
This is similar to commit bc0bdc5afaa7 ("RDMA/cma: Do not change route.addr.src_addr.ss_family")
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Analysis
by VulDB Data Team • 11/24/2025
The vulnerability CVE-2022-48925 affects the Linux kernel's RDMA (Remote Direct Memory Access) communication management subsystem, specifically within the cma.c driver component. This issue resides in the RDMA connection management functionality that handles socket address resolution and state transitions for RDMA connections. The flaw occurs in the resolve_prepare_src() function which is responsible for preparing source addresses during connection establishment processes. When the function encounters a non-idle state, it should immediately fail and refrain from modifying global state variables, but instead it unconditionally overwrites the source address with a temporary any address. This behavior creates a critical race condition and state corruption scenario that can lead to severe system instability.
The technical implementation flaw stems from improper state validation within the RDMA connection management logic. When a connection identifier transitions through various states such as RDMA_CM_LISTEN, the function resolve_prepare_src() should abort immediately if the state is not idle, but it fails to respect this constraint. Instead, it proceeds to overwrite the src_addr field with a temporary any address constructed from the destination address. This direct modification of global state variables without proper state checking creates a dangerous condition where memory corruption can occur. The specific failure manifests when the cma_cancel_operation() function attempts to validate the source address using cma_any_addr() and checks id_priv->cma_dev, which triggers use-after-free conditions due to the corrupted address structure.
The operational impact of this vulnerability is severe and can result in kernel crashes, memory corruption, and system instability. The reported KASAN (Kernel Address Sanitizer) trace demonstrates a use-after-free error occurring in __list_add_valid function, indicating that rdma_id_private structures are being destroyed without proper cleanup through cma_cancel_listens(). This memory corruption pattern suggests that the kernel's list management system attempts to operate on freed memory locations, leading to potential privilege escalation opportunities or denial of service conditions. The vulnerability is particularly dangerous in environments utilizing RDMA for high-performance networking where connection management is critical for system stability and security. The issue affects systems running Linux kernel versions prior to the fix, making it a significant concern for production environments relying on RDMA functionality.
The mitigation strategy involves restructuring the address preparation logic to avoid direct modification of global state variables during invalid state transitions. The recommended fix implements a stack-based approach where temporary any addresses are constructed explicitly on the stack rather than reusing the src_addr memory. This approach aligns with the principle of least privilege and defensive programming, ensuring that global state modifications only occur when proper validation conditions are met. The solution mirrors the approach taken in commit bc0bdc5afaa7 which addressed similar issues in RDMA/cma subsystem by preventing source address modifications during invalid state transitions. Organizations should apply the kernel patches addressing this CVE immediately and conduct thorough testing of RDMA-dependent applications to ensure proper functionality after the fix. The mitigation also includes monitoring for potential memory corruption patterns and implementing additional validation checks in RDMA connection management code paths to prevent similar issues from emerging in the future.
This vulnerability maps to CWE-362 (Concurrent Execution using Shared Resource with Improper Synchronization) and CWE-476 (NULL Pointer Dereference) within the Common Weakness Enumeration framework. From the MITRE ATT&CK framework perspective, this represents a privilege escalation vector through kernel memory corruption (T1068) and potentially system instability (T1499.001) that could be leveraged by adversaries to gain unauthorized access or cause service disruption in RDMA-enabled network environments. The vulnerability demonstrates the critical importance of proper state management and memory safety in kernel-level networking components where improper handling of shared resources can lead to catastrophic system failures and security breaches.