net/smc: release the internal TCP sock on IPPROTO_SMC socket creation failure
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.12.110, 6.18.52, 7.2.6
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
In the Linux kernel, the following vulnerability has been resolved: net/smc: release the internal TCP sock on IPPROTO_SMC socket creation failure IPPROTO_SMC sockets create an internal TCP sock ("clcsock") from the proto->init hook. When socket creation fails after proto->init has run - e.g. a cgroup BPF program attached to BPF_CGROUP_INET_SOCK_CREATE denies the socket - sk_common_release() only invokes sk_prot->destroy if it is set, but neither smc_inet_prot nor smc_inet6_prot defines it, and smc_destruct() returns early unless sk_state is SMC_CLOSED. As a result, every failing socket(AF_INET, SOCK_STREAM, IPPROTO_SMC) call leaks one tcp_sock, so an unprivileged task able to attach a deny-all BPF_CGROUP_INET_SOCK_CREATE program to its own cgroup can grow kernel memory unboundedly. Add a .destroy hook to both protos that releases the clcsock via smc_clcsock_release(). smc_sk_init() hashes the sock into the smc hashinfo before the clcsock is created, and smc_diag dumps walk that hash dereferencing smc->clcsock without taking clcsock_release_lock, while sk_common_release() calls .destroy before .unhash. Unhash the sock before releasing the clcsock, as __smc_release() does, so a concurrent dump cannot observe the release; the second unhash in sk_common_release() is a no-op.
Timeline
- CVE published
- Record last updated
Affected versions
- Linux Linux
From d25a92ccae6bed02327b63d138e12e7806830f78 · fixed in 2f4ece7fed6d915ec64b7735962c0d84d6261032; From d25a92ccae6bed02327b63d138e12e7806830f78 · fixed in 84180988a455fd8e147c6b35c8df65d8b8cc76c2; From d25a92ccae6bed02327b63d138e12e7806830f78 · fixed in 94a913cd521c0f0408820bcdbd80dadf076d97b5; From d25a92ccae6bed02327b63d138e12e7806830f78 · fixed in cec261b0b4c5c0b044165303198d10ffcdf3414c
- Linux Linux
6.11
- KernelLinux
From 6.11.0 · fixed in 6.12.110; From 6.13.0 · fixed in 6.18.52; From 6.19.0 · fixed in 7.2.6