Description
In the Linux kernel, the following vulnerability has been resolved:

net: ipv4: fix memory leak in ip_mc_add1_src

BUG: memory leak
unreferenced object 0xffff888101bc4c00 (size 32):
comm "syz-executor527", pid 360, jiffies 4294807421 (age 19.329s)
hex dump (first 32 bytes):
00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................
01 00 00 00 00 00 00 00 ac 14 14 bb 00 00 02 00 ................
backtrace:
[<00000000f17c5244>] kmalloc include/linux/slab.h:558 [inline]
[<00000000f17c5244>] kzalloc include/linux/slab.h:688 [inline]
[<00000000f17c5244>] ip_mc_add1_src net/ipv4/igmp.c:1971 [inline]
[<00000000f17c5244>] ip_mc_add_src+0x95f/0xdb0 net/ipv4/igmp.c:2095
[<000000001cb99709>] ip_mc_source+0x84c/0xea0 net/ipv4/igmp.c:2416
[<0000000052cf19ed>] do_ip_setsockopt net/ipv4/ip_sockglue.c:1294 [inline]
[<0000000052cf19ed>] ip_setsockopt+0x114b/0x30c0 net/ipv4/ip_sockglue.c:1423
[<00000000477edfbc>] raw_setsockopt+0x13d/0x170 net/ipv4/raw.c:857
[<00000000e75ca9bb>] __sys_setsockopt+0x158/0x270 net/socket.c:2117
[<00000000bdb993a8>] __do_sys_setsockopt net/socket.c:2128 [inline]
[<00000000bdb993a8>] __se_sys_setsockopt net/socket.c:2125 [inline]
[<00000000bdb993a8>] __x64_sys_setsockopt+0xba/0x150 net/socket.c:2125
[<000000006a1ffdbd>] do_syscall_64+0x40/0x80 arch/x86/entry/common.c:47
[<00000000b11467c4>] entry_SYSCALL_64_after_hwframe+0x44/0xae

In commit 24803f38a5c0 ("igmp: do not remove igmp souce list info when set
link down"), the ip_mc_clear_src() in ip_mc_destroy_dev() was removed,
because it was also called in igmpv3_clear_delrec().

Rough callgraph:

inetdev_destroy
-> ip_mc_destroy_dev
-> igmpv3_clear_delrec
-> ip_mc_clear_src
-> RCU_INIT_POINTER(dev->ip_ptr, NULL)

However, ip_mc_clear_src() called in igmpv3_clear_delrec() doesn't
release in_dev->mc_list->sources. And RCU_INIT_POINTER() assigns the
NULL to dev->ip_ptr. As a result, in_dev cannot be obtained through
inetdev_by_index() and then in_dev->mc_list->sources cannot be released
by ip_mc_del1_src() in the sock_close. Rough call sequence goes like:

sock_close
-> __sock_release
-> inet_release
-> ip_mc_drop_socket
-> inetdev_by_index
-> ip_mc_leave_src
-> ip_mc_del_src
-> ip_mc_del1_src

So we still need to call ip_mc_clear_src() in ip_mc_destroy_dev() to free
in_dev->mc_list->sources.
Published: 2024-05-21
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
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Remediation

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Advisories
Source ID Title
EUVD EUVD EUVD-2021-33886 In the Linux kernel, the following vulnerability has been resolved: net: ipv4: fix memory leak in ip_mc_add1_src BUG: memory leak unreferenced object 0xffff888101bc4c00 (size 32): comm "syz-executor527", pid 360, jiffies 4294807421 (age 19.329s) hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 01 00 00 00 00 00 00 00 ac 14 14 bb 00 00 02 00 ................ backtrace: [<00000000f17c5244>] kmalloc include/linux/slab.h:558 [inline] [<00000000f17c5244>] kzalloc include/linux/slab.h:688 [inline] [<00000000f17c5244>] ip_mc_add1_src net/ipv4/igmp.c:1971 [inline] [<00000000f17c5244>] ip_mc_add_src+0x95f/0xdb0 net/ipv4/igmp.c:2095 [<000000001cb99709>] ip_mc_source+0x84c/0xea0 net/ipv4/igmp.c:2416 [<0000000052cf19ed>] do_ip_setsockopt net/ipv4/ip_sockglue.c:1294 [inline] [<0000000052cf19ed>] ip_setsockopt+0x114b/0x30c0 net/ipv4/ip_sockglue.c:1423 [<00000000477edfbc>] raw_setsockopt+0x13d/0x170 net/ipv4/raw.c:857 [<00000000e75ca9bb>] __sys_setsockopt+0x158/0x270 net/socket.c:2117 [<00000000bdb993a8>] __do_sys_setsockopt net/socket.c:2128 [inline] [<00000000bdb993a8>] __se_sys_setsockopt net/socket.c:2125 [inline] [<00000000bdb993a8>] __x64_sys_setsockopt+0xba/0x150 net/socket.c:2125 [<000000006a1ffdbd>] do_syscall_64+0x40/0x80 arch/x86/entry/common.c:47 [<00000000b11467c4>] entry_SYSCALL_64_after_hwframe+0x44/0xae In commit 24803f38a5c0 ("igmp: do not remove igmp souce list info when set link down"), the ip_mc_clear_src() in ip_mc_destroy_dev() was removed, because it was also called in igmpv3_clear_delrec(). Rough callgraph: inetdev_destroy -> ip_mc_destroy_dev -> igmpv3_clear_delrec -> ip_mc_clear_src -> RCU_INIT_POINTER(dev->ip_ptr, NULL) However, ip_mc_clear_src() called in igmpv3_clear_delrec() doesn't release in_dev->mc_list->sources. And RCU_INIT_POINTER() assigns the NULL to dev->ip_ptr. As a result, in_dev cannot be obtained through inetdev_by_index() and then in_dev->mc_list->sources cannot be released by ip_mc_del1_src() in the sock_close. Rough call sequence goes like: sock_close -> __sock_release -> inet_release -> ip_mc_drop_socket -> inetdev_by_index -> ip_mc_leave_src -> ip_mc_del_src -> ip_mc_del1_src So we still need to call ip_mc_clear_src() in ip_mc_destroy_dev() to free in_dev->mc_list->sources.
History

Fri, 04 Apr 2025 15:00:00 +0000

Type Values Removed Values Added
CPEs cpe:2.3:o:linux:linux_kernel:5.13:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc5:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:5.13:rc6:*:*:*:*:*:*

Mon, 04 Nov 2024 12:15:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-05-11T13:50:37.983Z

Reserved: 2024-04-10T18:59:19.532Z

Link: CVE-2021-47238

cve-icon Vulnrichment

Updated: 2024-08-04T05:32:07.941Z

cve-icon NVD

Status : Analyzed

Published: 2024-05-21T15:15:13.017

Modified: 2025-04-04T14:31:03.253

Link: CVE-2021-47238

cve-icon Redhat

Severity : Moderate

Publid Date: 2024-05-21T00:00:00Z

Links: CVE-2021-47238 - Bugzilla

cve-icon OpenCVE Enrichment

No data.

Weaknesses