CVE-2021-47237

net: hamradio: fix memory leak in mkiss_close

State: Published
Severity: Not scored
Published: May 21, 2024
Updated: May 11, 2026
Reserved: Apr 10, 2024

Description

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: [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0 [<ffffffff8706e7e8>] alloc_netdev_mqs+0x98/0xe80 [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110 [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200 [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>] 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: [<ffffffff8709f68b>] __hw_addr_create_ex+0x5b/0x310 [<ffffffff8709fb38>] __hw_addr_add_ex+0x1f8/0x2b0 [<ffffffff870a0c7b>] dev_addr_init+0x10b/0x1f0 [<ffffffff8706e88b>] alloc_netdev_mqs+0x13b/0xe80 [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110 [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200 [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>] 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: [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0 [<ffffffff8706eec7>] alloc_netdev_mqs+0x777/0xe80 [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110 [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200 [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>] 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: [<ffffffff81a27201>] kvmalloc_node+0x61/0xf0 [<ffffffff8706f062>] alloc_netdev_mqs+0x912/0xe80 [<ffffffff84e64192>] mkiss_open+0xb2/0x6f0 [1] [<ffffffff842355db>] tty_ldisc_open+0x9b/0x110 [<ffffffff84236488>] tty_set_ldisc+0x2e8/0x670 [<ffffffff8421f7f3>] tty_ioctl+0xda3/0x1440 [<ffffffff81c9f273>] __x64_sys_ioctl+0x193/0x200 [<ffffffff8911263a>] do_syscall_64+0x3a/0xb0 [<ffffffff89200068>] entry_SYSCALL_64_after_hwframe+0x44/0xae

Scores

The record has no CVSS score.

Weaknesses

The record names no weakness.

Affected Products

Product	Versions
LinuxLinux	815f62bf742718458ba822a7e1f51f285eb997f2 to before c634ba0b4159838ff45a60d3a0ace3b4118077a5Affected 815f62bf742718458ba822a7e1f51f285eb997f2 to before 3942d0f9ace1a95a74930b5b4fc0e5005c62b37bAffected 815f62bf742718458ba822a7e1f51f285eb997f2 to before 765a8a04f828db7222b36a42b1031f576bfe95c3Affected 815f62bf742718458ba822a7e1f51f285eb997f2 to before c16c4716a1b5ba4f83c7e00da457cba06761f119Affected 815f62bf742718458ba822a7e1f51f285eb997f2 to before a49cbb762ef20655f5c91abdc13658b0af5e159dAffected 815f62bf742718458ba822a7e1f51f285eb997f2 to before 290b0b6432e2599021db0b8d6046f756d931c29fAffected 815f62bf742718458ba822a7e1f51f285eb997f2 to before f4de2b43d13b7cf3ced9310e371b90c836dbd7cdAffected 815f62bf742718458ba822a7e1f51f285eb997f2 to before 7edcc682301492380fbdd604b4516af5ae667a13Affected
LinuxLinux	2.6.14Affected before 2.6.14Not affected 4.4.274 through 4.4.Not affected 4.9.274 through 4.9.Not affected 4.14.238 through 4.14.Not affected 4.19.196 through 4.19.Not affected 5.4.128 through 5.4.Not affected 5.10.46 through 5.10.Not affected 5.12.13 through 5.12.*Not affected 5.13 and laterNot affected

Product

Versions

LinuxLinux

815f62bf742718458ba822a7e1f51f285eb997f2 to before c634ba0b4159838ff45a60d3a0ace3b4118077a5Affected
815f62bf742718458ba822a7e1f51f285eb997f2 to before 3942d0f9ace1a95a74930b5b4fc0e5005c62b37bAffected
815f62bf742718458ba822a7e1f51f285eb997f2 to before 765a8a04f828db7222b36a42b1031f576bfe95c3Affected
815f62bf742718458ba822a7e1f51f285eb997f2 to before c16c4716a1b5ba4f83c7e00da457cba06761f119Affected
815f62bf742718458ba822a7e1f51f285eb997f2 to before a49cbb762ef20655f5c91abdc13658b0af5e159dAffected
815f62bf742718458ba822a7e1f51f285eb997f2 to before 290b0b6432e2599021db0b8d6046f756d931c29fAffected
815f62bf742718458ba822a7e1f51f285eb997f2 to before f4de2b43d13b7cf3ced9310e371b90c836dbd7cdAffected
815f62bf742718458ba822a7e1f51f285eb997f2 to before 7edcc682301492380fbdd604b4516af5ae667a13Affected

LinuxLinux

2.6.14Affected
before 2.6.14Not affected
4.4.274 through 4.4.*Not affected
4.9.274 through 4.9.*Not affected
4.14.238 through 4.14.*Not affected
4.19.196 through 4.19.*Not affected
5.4.128 through 5.4.*Not affected
5.10.46 through 5.10.*Not affected
5.12.13 through 5.12.*Not affected
5.13 and laterNot affected

References

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