CVE-2021-46929 (GCVE-0-2021-46929)
Vulnerability from cvelistv5 – Published: 2024-02-27 09:43 – Updated: 2026-08-05 08:45
VLAI
EPSS
VEX
Title
sctp: use call_rcu to free endpoint
Summary
In the Linux kernel, the following vulnerability has been resolved:
sctp: use call_rcu to free endpoint
This patch is to delay the endpoint free by calling call_rcu() to fix
another use-after-free issue in sctp_sock_dump():
BUG: KASAN: use-after-free in __lock_acquire+0x36d9/0x4c20
Call Trace:
__lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218
lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844
__raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]
_raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168
spin_lock_bh include/linux/spinlock.h:334 [inline]
__lock_sock+0x203/0x350 net/core/sock.c:2253
lock_sock_nested+0xfe/0x120 net/core/sock.c:2774
lock_sock include/net/sock.h:1492 [inline]
sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324
sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c:5091
sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527
__inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049
inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065
netlink_dump+0x606/0x1080 net/netlink/af_netlink.c:2244
__netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352
netlink_dump_start include/linux/netlink.h:216 [inline]
inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170
__sock_diag_cmd net/core/sock_diag.c:232 [inline]
sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263
netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477
sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:274
This issue occurs when asoc is peeled off and the old sk is freed after
getting it by asoc->base.sk and before calling lock_sock(sk).
To prevent the sk free, as a holder of the sk, ep should be alive when
calling lock_sock(). This patch uses call_rcu() and moves sock_put and
ep free into sctp_endpoint_destroy_rcu(), so that it's safe to try to
hold the ep under rcu_read_lock in sctp_transport_traverse_process().
If sctp_endpoint_hold() returns true, it means this ep is still alive
and we have held it and can continue to dump it; If it returns false,
it means this ep is dead and can be freed after rcu_read_unlock, and
we should skip it.
In sctp_sock_dump(), after locking the sk, if this ep is different from
tsp->asoc->ep, it means during this dumping, this asoc was peeled off
before calling lock_sock(), and the sk should be skipped; If this ep is
the same with tsp->asoc->ep, it means no peeloff happens on this asoc,
and due to lock_sock, no peeloff will happen either until release_sock.
Note that delaying endpoint free won't delay the port release, as the
port release happens in sctp_endpoint_destroy() before calling call_rcu().
Also, freeing endpoint by call_rcu() makes it safe to access the sk by
asoc->base.sk in sctp_assocs_seq_show() and sctp_rcv().
Thanks Jones to bring this issue up.
v1->v2:
- improve the changelog.
- add kfree(ep) into sctp_endpoint_destroy_rcu(), as Jakub noticed.
Severity
7.8 (High)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2024-09-10 16:02 UTC
Assigner
References
6 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab , < 8873140f95d4977bf37e4cf0d5c5e3f6e34cdd3e
(git)
Affected: d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab , < af6e6e58f7ebf86b4e7201694b1e4f3a62cbc3ec (git) Affected: d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab , < 831de271452b87657fcf8d715ee20519b79caef5 (git) Affected: d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab , < 769d14abd35e0e153b5149c3e1e989a9d719e3ff (git) Affected: d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab , < 75799e71df1da11394740b43ae5686646179561d (git) Affected: d25adbeb0cdb860fb39e09cdd025e9cfc954c5ab , < 5ec7d18d1813a5bead0b495045606c93873aecbb (git) |
guessed | |
| Linux | Linux |
Affected:
4.14
Unaffected: 0 , < 4.14 (semver) Unaffected: 4.14.261 , ≤ 4.14.* (semver) Unaffected: 4.19.224 , ≤ 4.19.* (semver) Unaffected: 5.4.170 , ≤ 5.4.* (semver) Unaffected: 5.10.90 , ≤ 5.10.* (semver) Unaffected: 5.15.13 , ≤ 5.15.* (semver) Unaffected: 5.16 , ≤ * (original_commit_for_fix) |
guessed |
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: use call_rcu to free endpoint\n\nThis patch is to delay the endpoint free by calling call_rcu() to fix\nanother use-after-free issue in sctp_sock_dump():\n\n BUG: KASAN: use-after-free in __lock_acquire+0x36d9/0x4c20\n Call Trace:\n __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218\n lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844\n __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]\n _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168\n spin_lock_bh include/linux/spinlock.h:334 [inline]\n __lock_sock+0x203/0x350 net/core/sock.c:2253\n lock_sock_nested+0xfe/0x120 net/core/sock.c:2774\n lock_sock include/net/sock.h:1492 [inline]\n sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324\n sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c:5091\n sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527\n __inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049\n inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065\n netlink_dump+0x606/0x1080 net/netlink/af_netlink.c:2244\n __netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352\n netlink_dump_start include/linux/netlink.h:216 [inline]\n inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170\n __sock_diag_cmd net/core/sock_diag.c:232 [inline]\n sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263\n netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477\n sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:274\n\nThis issue occurs when asoc is peeled off and the old sk is freed after\ngetting it by asoc-\u003ebase.sk and before calling lock_sock(sk).\n\nTo prevent the sk free, as a holder of the sk, ep should be alive when\ncalling lock_sock(). This patch uses call_rcu() and moves sock_put and\nep free into sctp_endpoint_destroy_rcu(), so that it\u0027s safe to try to\nhold the ep under rcu_read_lock in sctp_transport_traverse_process().\n\nIf sctp_endpoint_hold() returns true, it means this ep is still alive\nand we have held it and can continue to dump it; If it returns false,\nit means this ep is dead and can be freed after rcu_read_unlock, and\nwe should skip it.\n\nIn sctp_sock_dump(), after locking the sk, if this ep is different from\ntsp-\u003easoc-\u003eep, it means during this dumping, this asoc was peeled off\nbefore calling lock_sock(), and the sk should be skipped; If this ep is\nthe same with tsp-\u003easoc-\u003eep, it means no peeloff happens on this asoc,\nand due to lock_sock, no peeloff will happen either until release_sock.\n\nNote that delaying endpoint free won\u0027t delay the port release, as the\nport release happens in sctp_endpoint_destroy() before calling call_rcu().\nAlso, freeing endpoint by call_rcu() makes it safe to access the sk by\nasoc-\u003ebase.sk in sctp_assocs_seq_show() and sctp_rcv().\n\nThanks Jones to bring this issue up.\n\nv1-\u003ev2:\n - improve the changelog.\n - add kfree(ep) into sctp_endpoint_destroy_rcu(), as Jakub noticed."
},
{
"lang": "es",
"value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: sctp: use call_rcu para liberar el endpoint. Este parche tiene como objetivo retrasar la liberaci\u00f3n del endpoint llamando a call_rcu() para solucionar otro problema de use-after-free en sctp_sock_dump(): ERROR: KASAN: use-after-free en __lock_acquire+0x36d9/0x4c20 Rastreo de llamadas: __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock_bh include/linux/spinlock_api_smp.h :135 [en l\u00ednea] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168 spin_lock_bh include/linux/spinlock.h:334 [en l\u00ednea] __lock_sock+0x203/0x350 net/core/sock.c:2253 lock_sock_nested+0xfe/ 0x120 net/core/sock.c:2774 lock_sock include/net/sock.h:1492 [en l\u00ednea] sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324 sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c: 5091 sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527 __inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049 inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065 netlink_dump+0x6 06/0x1080 neto/ netlink/af_netlink.c:2244 __netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:216 [en l\u00ednea] inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170 __sock_diag_cm re neto /core/sock_diag.c:232 [en l\u00ednea] sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477 sock_diag_rcv+0x2a/0x40 net/core/sock_diag. c:274 Este problema ocurre cuando se quita asoc y se libera el sk antiguo despu\u00e9s de obtenerlo mediante asoc-\u0026gt;base.sk y antes de llamar a lock_sock(sk). Para evitar que sk se libere, como titular de sk, ep debe estar activo al llamar a lock_sock(). Este parche usa call_rcu() y mueve sock_put y ep free a sctp_endpoint_destroy_rcu(), por lo que es seguro intentar mantener el ep bajo rcu_read_lock en sctp_transport_traverse_process(). Si sctp_endpoint_hold() devuelve verdadero, significa que este ep todav\u00eda est\u00e1 vivo, lo hemos retenido y podemos continuar descart\u00e1ndolo; Si devuelve falso, significa que este ep est\u00e1 muerto y puede liberarse despu\u00e9s de rcu_read_unlock, y debemos omitirlo. En sctp_sock_dump(), despu\u00e9s de bloquear el sk, si este ep es diferente de tsp-\u0026gt;asoc-\u0026gt;ep, significa que durante este volcado, este asoc se elimin\u00f3 antes de llamar a lock_sock(), y el sk debe omitirse; Si este ep es el mismo con tsp-\u0026gt;asoc-\u0026gt;ep, significa que no se produce ning\u00fan despegue en este asoc y, debido a lock_sock, tampoco se producir\u00e1 ning\u00fan despegue hasta que se libere_sock. Tenga en cuenta que retrasar la liberaci\u00f3n del endpoint no retrasar\u00e1 la liberaci\u00f3n del puerto, ya que la liberaci\u00f3n del puerto ocurre en sctp_endpoint_destroy() antes de llamar a call_rcu(). Adem\u00e1s, liberar el endpoint mediante call_rcu() hace que sea seguro acceder a sk mediante asoc-\u0026gt;base.sk en sctp_assocs_seq_show() y sctp_rcv(). Gracias Jones por plantear este problema. v1-\u0026gt;v2: - mejorar el registro de cambios. - agregue kfree(ep) a sctp_endpoint_destroy_rcu(), como not\u00f3 Jakub."
}
],
"id": "CVE-2021-46929",
"lastModified": "2024-11-21T06:34:57.380",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 5.5,
"baseSeverity": "MEDIUM",
"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2024-02-27T10:15:07.573",
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"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"weaknesses": [
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"value": "CWE-416"
}
],
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"net/sctp/endpointola.c",
"net/sctp/socket.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"net/sctp/socket.c"
],
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{
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},
{
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"version": "4.19.224",
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},
{
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{
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},
{
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},
{
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"status": "unaffected",
"version": "5.16",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
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],
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: use call_rcu to free endpoint\n\nThis patch is to delay the endpoint free by calling call_rcu() to fix\nanother use-after-free issue in sctp_sock_dump():\n\n BUG: KASAN: use-after-free in __lock_acquire+0x36d9/0x4c20\n Call Trace:\n __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218\n lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844\n __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]\n _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168\n spin_lock_bh include/linux/spinlock.h:334 [inline]\n __lock_sock+0x203/0x350 net/core/sock.c:2253\n lock_sock_nested+0xfe/0x120 net/core/sock.c:2774\n lock_sock include/net/sock.h:1492 [inline]\n sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324\n sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c:5091\n sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527\n __inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049\n inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065\n netlink_dump+0x606/0x1080 net/netlink/af_netlink.c:2244\n __netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352\n netlink_dump_start include/linux/netlink.h:216 [inline]\n inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170\n __sock_diag_cmd net/core/sock_diag.c:232 [inline]\n sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263\n netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477\n sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:274\n\nThis issue occurs when asoc is peeled off and the old sk is freed after\ngetting it by asoc-\u003ebase.sk and before calling lock_sock(sk).\n\nTo prevent the sk free, as a holder of the sk, ep should be alive when\ncalling lock_sock(). This patch uses call_rcu() and moves sock_put and\nep free into sctp_endpoint_destroy_rcu(), so that it\u0027s safe to try to\nhold the ep under rcu_read_lock in sctp_transport_traverse_process().\n\nIf sctp_endpoint_hold() returns true, it means this ep is still alive\nand we have held it and can continue to dump it; If it returns false,\nit means this ep is dead and can be freed after rcu_read_unlock, and\nwe should skip it.\n\nIn sctp_sock_dump(), after locking the sk, if this ep is different from\ntsp-\u003easoc-\u003eep, it means during this dumping, this asoc was peeled off\nbefore calling lock_sock(), and the sk should be skipped; If this ep is\nthe same with tsp-\u003easoc-\u003eep, it means no peeloff happens on this asoc,\nand due to lock_sock, no peeloff will happen either until release_sock.\n\nNote that delaying endpoint free won\u0027t delay the port release, as the\nport release happens in sctp_endpoint_destroy() before calling call_rcu().\nAlso, freeing endpoint by call_rcu() makes it safe to access the sk by\nasoc-\u003ebase.sk in sctp_assocs_seq_show() and sctp_rcv().\n\nThanks Jones to bring this issue up.\n\nv1-\u003ev2:\n - improve the changelog.\n - add kfree(ep) into sctp_endpoint_destroy_rcu(), as Jakub noticed."
},
{
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"value": "En el kernel de Linux, se resolvi\u00f3 la siguiente vulnerabilidad: sctp: use call_rcu para liberar el endpoint. Este parche tiene como objetivo retrasar la liberaci\u00f3n del endpoint llamando a call_rcu() para solucionar otro problema de use-after-free en sctp_sock_dump(): ERROR: KASAN: use-after-free en __lock_acquire+0x36d9/0x4c20 Rastreo de llamadas: __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218 lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844 __raw_spin_lock_bh include/linux/spinlock_api_smp.h :135 [en l\u00ednea] _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168 spin_lock_bh include/linux/spinlock.h:334 [en l\u00ednea] __lock_sock+0x203/0x350 net/core/sock.c:2253 lock_sock_nested+0xfe/ 0x120 net/core/sock.c:2774 lock_sock include/net/sock.h:1492 [en l\u00ednea] sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324 sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c: 5091 sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527 __inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049 inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065 netlink_dump+0x6 06/0x1080 neto/ netlink/af_netlink.c:2244 __netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352 netlink_dump_start include/linux/netlink.h:216 [en l\u00ednea] inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170 __sock_diag_cm re neto /core/sock_diag.c:232 [en l\u00ednea] sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477 sock_diag_rcv+0x2a/0x40 net/core/sock_diag. c:274 Este problema ocurre cuando se quita asoc y se libera el sk antiguo despu\u00e9s de obtenerlo mediante asoc-\u0026gt;base.sk y antes de llamar a lock_sock(sk). Para evitar que sk se libere, como titular de sk, ep debe estar activo al llamar a lock_sock(). Este parche usa call_rcu() y mueve sock_put y ep free a sctp_endpoint_destroy_rcu(), por lo que es seguro intentar mantener el ep bajo rcu_read_lock en sctp_transport_traverse_process(). Si sctp_endpoint_hold() devuelve verdadero, significa que este ep todav\u00eda est\u00e1 vivo, lo hemos retenido y podemos continuar descart\u00e1ndolo; Si devuelve falso, significa que este ep est\u00e1 muerto y puede liberarse despu\u00e9s de rcu_read_unlock, y debemos omitirlo. En sctp_sock_dump(), despu\u00e9s de bloquear el sk, si este ep es diferente de tsp-\u0026gt;asoc-\u0026gt;ep, significa que durante este volcado, este asoc se elimin\u00f3 antes de llamar a lock_sock(), y el sk debe omitirse; Si este ep es el mismo con tsp-\u0026gt;asoc-\u0026gt;ep, significa que no se produce ning\u00fan despegue en este asoc y, debido a lock_sock, tampoco se producir\u00e1 ning\u00fan despegue hasta que se libere_sock. Tenga en cuenta que retrasar la liberaci\u00f3n del endpoint no retrasar\u00e1 la liberaci\u00f3n del puerto, ya que la liberaci\u00f3n del puerto ocurre en sctp_endpoint_destroy() antes de llamar a call_rcu(). Adem\u00e1s, liberar el endpoint mediante call_rcu() hace que sea seguro acceder a sk mediante asoc-\u0026gt;base.sk en sctp_assocs_seq_show() y sctp_rcv(). Gracias Jones por plantear este problema. v1-\u0026gt;v2: - mejorar el registro de cambios. - agregue kfree(ep) a sctp_endpoint_destroy_rcu(), como not\u00f3 Jakub."
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsctp: use call_rcu to free endpoint\n\nThis patch is to delay the endpoint free by calling call_rcu() to fix\nanother use-after-free issue in sctp_sock_dump():\n\n BUG: KASAN: use-after-free in __lock_acquire+0x36d9/0x4c20\n Call Trace:\n __lock_acquire+0x36d9/0x4c20 kernel/locking/lockdep.c:3218\n lock_acquire+0x1ed/0x520 kernel/locking/lockdep.c:3844\n __raw_spin_lock_bh include/linux/spinlock_api_smp.h:135 [inline]\n _raw_spin_lock_bh+0x31/0x40 kernel/locking/spinlock.c:168\n spin_lock_bh include/linux/spinlock.h:334 [inline]\n __lock_sock+0x203/0x350 net/core/sock.c:2253\n lock_sock_nested+0xfe/0x120 net/core/sock.c:2774\n lock_sock include/net/sock.h:1492 [inline]\n sctp_sock_dump+0x122/0xb20 net/sctp/diag.c:324\n sctp_for_each_transport+0x2b5/0x370 net/sctp/socket.c:5091\n sctp_diag_dump+0x3ac/0x660 net/sctp/diag.c:527\n __inet_diag_dump+0xa8/0x140 net/ipv4/inet_diag.c:1049\n inet_diag_dump+0x9b/0x110 net/ipv4/inet_diag.c:1065\n netlink_dump+0x606/0x1080 net/netlink/af_netlink.c:2244\n __netlink_dump_start+0x59a/0x7c0 net/netlink/af_netlink.c:2352\n netlink_dump_start include/linux/netlink.h:216 [inline]\n inet_diag_handler_cmd+0x2ce/0x3f0 net/ipv4/inet_diag.c:1170\n __sock_diag_cmd net/core/sock_diag.c:232 [inline]\n sock_diag_rcv_msg+0x31d/0x410 net/core/sock_diag.c:263\n netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2477\n sock_diag_rcv+0x2a/0x40 net/core/sock_diag.c:274\n\nThis issue occurs when asoc is peeled off and the old sk is freed after\ngetting it by asoc-\u003ebase.sk and before calling lock_sock(sk).\n\nTo prevent the sk free, as a holder of the sk, ep should be alive when\ncalling lock_sock(). This patch uses call_rcu() and moves sock_put and\nep free into sctp_endpoint_destroy_rcu(), so that it\u0027s safe to try to\nhold the ep under rcu_read_lock in sctp_transport_traverse_process().\n\nIf sctp_endpoint_hold() returns true, it means this ep is still alive\nand we have held it and can continue to dump it; If it returns false,\nit means this ep is dead and can be freed after rcu_read_unlock, and\nwe should skip it.\n\nIn sctp_sock_dump(), after locking the sk, if this ep is different from\ntsp-\u003easoc-\u003eep, it means during this dumping, this asoc was peeled off\nbefore calling lock_sock(), and the sk should be skipped; If this ep is\nthe same with tsp-\u003easoc-\u003eep, it means no peeloff happens on this asoc,\nand due to lock_sock, no peeloff will happen either until release_sock.\n\nNote that delaying endpoint free won\u0027t delay the port release, as the\nport release happens in sctp_endpoint_destroy() before calling call_rcu().\nAlso, freeing endpoint by call_rcu() makes it safe to access the sk by\nasoc-\u003ebase.sk in sctp_assocs_seq_show() and sctp_rcv().\n\nThanks Jones to bring this issue up.\n\nv1-\u003ev2:\n - improve the changelog.\n - add kfree(ep) into sctp_endpoint_destroy_rcu(), as Jakub noticed."
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},
{
"url": "https://git.kernel.org/stable/c/831de271452b87657fcf8d715ee20519b79caef5"
},
{
"url": "https://git.kernel.org/stable/c/769d14abd35e0e153b5149c3e1e989a9d719e3ff"
},
{
"url": "https://git.kernel.org/stable/c/75799e71df1da11394740b43ae5686646179561d"
},
{
"url": "https://git.kernel.org/stable/c/5ec7d18d1813a5bead0b495045606c93873aecbb"
}
],
"title": "sctp: use call_rcu to free endpoint",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2021-46929",
"datePublished": "2024-02-27T09:43:58.047Z",
"dateReserved": "2024-02-25T13:45:52.720Z",
"dateUpdated": "2026-08-05T08:45:08.476Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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