Linux Kernel up to 5.12.12 mkiss_open memory leak

Summaryinfo

A vulnerability was found in Linux Kernel up to 5.12.12. It has been classified as critical. This issue affects the function mkiss_open. This manipulation causes memory leak. This vulnerability appears as CVE-2021-47237. There is no available exploit. Upgrading the affected component is recommended.

Detailsinfo

A vulnerability classified as critical was found in Linux Kernel up to 5.12.12. Affected by this vulnerability is the function mkiss_open. The manipulation with an unknown input leads to a memory leak vulnerability. The CWE definition for the vulnerability is CWE-401. The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory. As an impact it is known to affect availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: net: hamradio: fix memory leak in mkiss_close My local syzbot instance hit memory leak in mkiss_open()[1]. The problem was in missing free_netdev() in mkiss_close(). In mkiss_open() netdevice is allocated and then registered, but in mkiss_close() netdevice was only unregistered, but not freed. Fail log: BUG: memory leak unreferenced object 0xffff8880281ba000 (size 4096): comm "syz-executor.1", pid 11443, jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes): 61 78 30 00 00 00 00 00 00 00 00 00 00 00 00 00 ax0............. 00 27 fa 2a 80 88 ff ff 00 00 00 00 00 00 00 00 .'.*............ backtrace: [] kvmalloc_node+0x61/0xf0 [] alloc_netdev_mqs+0x98/0xe80 [] mkiss_open+0xb2/0x6f0 [1] [] tty_ldisc_open+0x9b/0x110 [] tty_set_ldisc+0x2e8/0x670 [] tty_ioctl+0xda3/0x1440 [] __x64_sys_ioctl+0x193/0x200 [] do_syscall_64+0x3a/0xb0 [] entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory leak unreferenced object 0xffff8880141a9a00 (size 96): comm "syz-executor.1", pid 11443, jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes): e8 a2 1b 28 80 88 ff ff e8 a2 1b 28 80 88 ff ff ...(.......(.... 98 92 9c aa b0 40 02 00 00 00 00 00 00 00 00 00 .....@.......... backtrace: [] __hw_addr_create_ex+0x5b/0x310 [] __hw_addr_add_ex+0x1f8/0x2b0 [] dev_addr_init+0x10b/0x1f0 [] alloc_netdev_mqs+0x13b/0xe80 [] mkiss_open+0xb2/0x6f0 [1] [] tty_ldisc_open+0x9b/0x110 [] tty_set_ldisc+0x2e8/0x670 [] tty_ioctl+0xda3/0x1440 [] __x64_sys_ioctl+0x193/0x200 [] do_syscall_64+0x3a/0xb0 [] entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory leak unreferenced object 0xffff8880219bfc00 (size 512): comm "syz-executor.1", pid 11443, jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes): 00 a0 1b 28 80 88 ff ff 80 8f b1 8d ff ff ff ff ...(............ 80 8f b1 8d ff ff ff ff 00 00 00 00 00 00 00 00 ................ backtrace: [] kvmalloc_node+0x61/0xf0 [] alloc_netdev_mqs+0x777/0xe80 [] mkiss_open+0xb2/0x6f0 [1] [] tty_ldisc_open+0x9b/0x110 [] tty_set_ldisc+0x2e8/0x670 [] tty_ioctl+0xda3/0x1440 [] __x64_sys_ioctl+0x193/0x200 [] do_syscall_64+0x3a/0xb0 [] entry_SYSCALL_64_after_hwframe+0x44/0xae BUG: memory leak unreferenced object 0xffff888029b2b200 (size 256): comm "syz-executor.1", pid 11443, jiffies 4295046091 (age 17.660s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [] kvmalloc_node+0x61/0xf0 [] alloc_netdev_mqs+0x912/0xe80 [] mkiss_open+0xb2/0x6f0 [1] [] tty_ldisc_open+0x9b/0x110 [] tty_set_ldisc+0x2e8/0x670 [] tty_ioctl+0xda3/0x1440 [] __x64_sys_ioctl+0x193/0x200 [] do_syscall_64+0x3a/0xb0 [] entry_SYSCALL_64_after_hwframe+0x44/0xae

The advisory is shared at git.kernel.org. This vulnerability is known as CVE-2021-47237 since 04/10/2024. The exploitation appears to be easy. Technical details are known, but no exploit is available.

Upgrading to version 4.4.274, 4.9.274, 4.14.238, 4.19.196, 5.4.128, 5.10.46 or 5.12.13 eliminates this vulnerability. Applying the patch c634ba0b4159/3942d0f9ace1/765a8a04f828/c16c4716a1b5/a49cbb762ef2/290b0b6432e2/f4de2b43d13b/7edcc6823014 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.

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 4.4.273
• 4.9.273
• 4.14.237
• 4.19.195
• 5.4.127
• 5.10.0
• 5.10.1
• 5.10.2
• 5.10.3
• 5.10.4
• 5.10.5
• 5.10.6
• 5.10.7
• 5.10.8
• 5.10.9
• 5.10.10
• 5.10.11
• 5.10.12
• 5.10.13
• 5.10.14
• 5.10.15
• 5.10.16
• 5.10.17
• 5.10.18
• 5.10.19
• 5.10.20
• 5.10.21
• 5.10.22
• 5.10.23
• 5.10.24
• 5.10.25
• 5.10.26
• 5.10.27
• 5.10.28
• 5.10.29
• 5.10.30
• 5.10.31
• 5.10.32
• 5.10.33
• 5.10.34
• 5.10.35
• 5.10.36
• 5.10.37
• 5.10.38
• 5.10.39
• 5.10.40
• 5.10.41
• 5.10.42
• 5.10.43
• 5.10.44
• 5.10.45
• 5.12.0
• 5.12.1
• 5.12.2
• 5.12.3
• 5.12.4
• 5.12.5
• 5.12.6
• 5.12.7
• 5.12.8
• 5.12.9
• 5.12.10
• 5.12.11
• 5.12.12

License

• open-source

Website

• Vendor: https://www.kernel.org/

CPE 2.3info

• 🔍
• 🔍
• 🔍

CPE 2.2info

• 🔍
• 🔍
• 🔍

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion