Linux Kernel up to 5.13.5 include/linux/slab.h io_init_wq_offload memory leak

Summaryinfo

A vulnerability, which was classified as critical, was found in Linux Kernel up to 5.13.5. This vulnerability affects the function io_init_wq_offload in the library include/linux/slab.h. Such manipulation leads to memory leak. This vulnerability is referenced as CVE-2021-47292. No exploit is available. You should upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 5.13.5. It has been rated as critical. Affected by this issue is the function io_init_wq_offload in the library include/linux/slab.h. The manipulation with an unknown input leads to a memory leak vulnerability. Using CWE to declare the problem leads to CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: io_uring: fix memleak in io_init_wq_offload() I got memory leak report when doing fuzz test: BUG: memory leak unreferenced object 0xffff888107310a80 (size 96): comm "syz-executor.6", pid 4610, jiffies 4295140240 (age 20.135s) hex dump (first 32 bytes): 01 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 ad 4e ad de ff ff ff ff 00 00 00 00 .....N.......... backtrace: [] kmalloc include/linux/slab.h:591 [inline] [] kzalloc include/linux/slab.h:721 [inline] [] io_init_wq_offload fs/io_uring.c:7920 [inline] [] io_uring_alloc_task_context+0x466/0x640 fs/io_uring.c:7955 [] __io_uring_add_tctx_node+0x256/0x360 fs/io_uring.c:9016 [] io_uring_add_tctx_node fs/io_uring.c:9052 [inline] [] __do_sys_io_uring_enter fs/io_uring.c:9354 [inline] [] __se_sys_io_uring_enter fs/io_uring.c:9301 [inline] [] __x64_sys_io_uring_enter+0xabc/0xc20 fs/io_uring.c:9301 [] do_syscall_x64 arch/x86/entry/common.c:50 [inline] [] do_syscall_64+0x3b/0x90 arch/x86/entry/common.c:80 [] entry_SYSCALL_64_after_hwframe+0x44/0xae CPU0 CPU1 io_uring_enter io_uring_enter io_uring_add_tctx_node io_uring_add_tctx_node __io_uring_add_tctx_node __io_uring_add_tctx_node io_uring_alloc_task_context io_uring_alloc_task_context io_init_wq_offload io_init_wq_offload hash = kzalloc hash = kzalloc ctx->hash_map = hash ctx->hash_map = hash <- one of the hash is leaked When calling io_uring_enter() in parallel, the 'hash_map' will be leaked, add uring_lock to protect 'hash_map'.

The advisory is shared for download at git.kernel.org. This vulnerability is handled as CVE-2021-47292 since 05/21/2024. The exploitation is known to be difficult. There are known technical details, but no exploit is available.

Upgrading to version 5.13.6 eliminates this vulnerability. Applying the patch 502731a03f27/362a9e652892 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.13.0
• 5.13.1
• 5.13.2
• 5.13.3
• 5.13.4
• 5.13.5

License

• open-source

Website

• Vendor: https://www.kernel.org/

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