CVE-2021-4442 (GCVE-0-2021-4442)
Vulnerability from cvelistv5
Published
2024-08-29 09:05
Modified
2026-05-11 13:44
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
tcp: add sanity tests to TCP_QUEUE_SEQ
Qingyu Li reported a syzkaller bug where the repro
changes RCV SEQ _after_ restoring data in the receive queue.
mprotect(0x4aa000, 12288, PROT_READ) = 0
mmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000
mmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000
mmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000
socket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3
setsockopt(3, SOL_TCP, TCP_REPAIR, [1], 4) = 0
connect(3, {sa_family=AF_INET6, sin6_port=htons(0), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, "::1", &sin6_addr), sin6_scope_id=0}, 28) = 0
setsockopt(3, SOL_TCP, TCP_REPAIR_QUEUE, [1], 4) = 0
sendmsg(3, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base="0x0000000000000003\0\0", iov_len=20}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 20
setsockopt(3, SOL_TCP, TCP_REPAIR, [0], 4) = 0
setsockopt(3, SOL_TCP, TCP_QUEUE_SEQ, [128], 4) = 0
recvfrom(3, NULL, 20, 0, NULL, NULL) = -1 ECONNRESET (Connection reset by peer)
syslog shows:
[ 111.205099] TCP recvmsg seq # bug 2: copied 80, seq 0, rcvnxt 80, fl 0
[ 111.207894] WARNING: CPU: 1 PID: 356 at net/ipv4/tcp.c:2343 tcp_recvmsg_locked+0x90e/0x29a0
This should not be allowed. TCP_QUEUE_SEQ should only be used
when queues are empty.
This patch fixes this case, and the tx path as well.
References
Impacted products
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: add sanity tests to TCP_QUEUE_SEQ\n\nQingyu Li reported a syzkaller bug where the repro\nchanges RCV SEQ _after_ restoring data in the receive queue.\n\nmprotect(0x4aa000, 12288, PROT_READ) = 0\nmmap(0x1ffff000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x1ffff000\nmmap(0x20000000, 16777216, PROT_READ|PROT_WRITE|PROT_EXEC, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x20000000\nmmap(0x21000000, 4096, PROT_NONE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0x21000000\nsocket(AF_INET6, SOCK_STREAM, IPPROTO_IP) = 3\nsetsockopt(3, SOL_TCP, TCP_REPAIR, [1], 4) = 0\nconnect(3, {sa_family=AF_INET6, sin6_port=htons(0), sin6_flowinfo=htonl(0), inet_pton(AF_INET6, \"::1\", \u0026sin6_addr), sin6_scope_id=0}, 28) = 0\nsetsockopt(3, SOL_TCP, TCP_REPAIR_QUEUE, [1], 4) = 0\nsendmsg(3, {msg_name=NULL, msg_namelen=0, msg_iov=[{iov_base=\"0x0000000000000003\\0\\0\", iov_len=20}], msg_iovlen=1, msg_controllen=0, msg_flags=0}, 0) = 20\nsetsockopt(3, SOL_TCP, TCP_REPAIR, [0], 4) = 0\nsetsockopt(3, SOL_TCP, TCP_QUEUE_SEQ, [128], 4) = 0\nrecvfrom(3, NULL, 20, 0, NULL, NULL) = -1 ECONNRESET (Connection reset by peer)\n\nsyslog shows:\n[ 111.205099] TCP recvmsg seq # bug 2: copied 80, seq 0, rcvnxt 80, fl 0\n[ 111.207894] WARNING: CPU: 1 PID: 356 at net/ipv4/tcp.c:2343 tcp_recvmsg_locked+0x90e/0x29a0\n\nThis should not be allowed. TCP_QUEUE_SEQ should only be used\nwhen queues are empty.\n\nThis patch fixes this case, and the tx path as well."
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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