CVE-2022-49793 in Linux
Summary
by MITRE • 05/01/2025
In the Linux kernel, the following vulnerability has been resolved:
iio: trigger: sysfs: fix possible memory leak in iio_sysfs_trig_init()
dev_set_name() allocates memory for name, it need be freed when device_add() fails, call put_device() to give up the reference that hold in device_initialize(), so that it can be freed in kobject_cleanup() when the refcount hit to 0.
Fault injection test can trigger this:
unreferenced object 0xffff8e8340a7b4c0 (size 32): comm "modprobe", pid 243, jiffies 4294678145 (age 48.845s) hex dump (first 32 bytes): 69 69 6f 5f 73 79 73 66 73 5f 74 72 69 67 67 65 iio_sysfs_trigge 72 00 a7 40 83 8e ff ff 00 86 13 c4 f6 ee ff ff r..@............ backtrace: [<0000000074999de8>] __kmem_cache_alloc_node+0x1e9/0x360
[<00000000497fd30b>] __kmalloc_node_track_caller+0x44/0x1a0
[<000000003636c520>] kstrdup+0x2d/0x60
[<0000000032f84da2>] kobject_set_name_vargs+0x1e/0x90
[<0000000092efe493>] dev_set_name+0x4e/0x70
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Analysis
by VulDB Data Team • 11/03/2025
The vulnerability CVE-2022-49793 represents a memory leak in the Linux kernel's industrial I/O subsystem, specifically within the sysfs trigger initialization functionality. This issue occurs in the iio_sysfs_trig_init() function where improper memory management leads to unreleased kernel objects. The flaw manifests when device_add() fails during the device initialization process, leaving allocated memory resources stranded in the kernel's memory management system. The vulnerability is particularly concerning as it demonstrates a classic memory management error where the dev_set_name() function allocates memory for device names but fails to properly release this allocation when subsequent operations encounter failures.
The technical root cause stems from the improper handling of device reference counting and memory allocation within the kernel's device model. When dev_set_name() is called, it allocates memory for the device name string, but this allocation becomes problematic when device_add() fails to complete successfully. The kernel's device initialization sequence holds references to these objects through device_initialize(), creating a scenario where memory cleanup does not occur properly. This situation results in kernel memory leaks that can accumulate over time, potentially leading to system instability or resource exhaustion. The vulnerability operates at the kernel level and affects the industrial I/O subsystem's ability to properly manage trigger devices through sysfs interfaces.
The operational impact of this vulnerability extends beyond simple memory consumption issues to potentially compromise system stability and performance. Memory leaks in kernel space can gradually degrade system performance, leading to increased latency and potential system crashes. The fault injection test scenario demonstrates how this vulnerability can be triggered through controlled conditions, making it particularly dangerous in production environments where such memory leaks can accumulate over extended periods. The vulnerability affects systems using the industrial I/O subsystem with sysfs trigger functionality, which is commonly found in embedded systems, industrial automation equipment, and sensor networks that rely on precise timing and device management.
Security implications of this vulnerability align with CWE-401, which specifically addresses memory leaks in software systems, and can be mapped to ATT&CK technique T1490 for resource exhaustion attacks. The vulnerability creates a potential attack surface where malicious actors could exploit memory leaks to cause denial of service conditions or system instability. Mitigation strategies should focus on proper memory management practices including ensuring that all allocated resources are properly freed regardless of operation success or failure states. The fix involves implementing correct reference counting mechanisms and ensuring that put_device() is called to release references when device_add() fails, allowing the kobject_cleanup() function to properly handle memory deallocation when reference counts reach zero. System administrators should apply kernel updates containing the patched code and monitor for memory consumption patterns that might indicate memory leak occurrences.