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CVE PROGRAM SOURCE RECORDUnscored

CVE-2026-52941

net/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint

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Status
Published
Published
Updated
Assigning organization
Linux

Description

In the Linux kernel, the following vulnerability has been resolved: net/smc: avoid NULL deref of conn->lnk in smc_msg_event tracepoint The smc_msg_event tracepoint class, shared by smc_tx_sendmsg and smc_rx_recvmsg, unconditionally dereferences smc->conn.lnk: __string(name, smc->conn.lnk->ibname) conn->lnk is only set for SMC-R; for SMC-D it is NULL. Other code on these paths already handles this (e.g. !conn->lnk in SMC_STAT_RMB_TX_SIZE_SMALL()). With the tracepoint enabled, the first sendmsg()/recvmsg() on an SMC-D socket crashes: Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [...] RIP: 0010:strlen+0x1e/0xa0 Call Trace: trace_event_raw_event_smc_msg_event (net/smc/smc_tracepoint.h:44) smc_rx_recvmsg (net/smc/smc_rx.c:515) smc_recvmsg (net/smc/af_smc.c:2859) __sys_recvfrom (net/socket.c:2315) __x64_sys_recvfrom (net/socket.c:2326) do_syscall_64 The faulting address 0x3e0 is offsetof(struct smc_link, ibname), confirming the NULL ->lnk deref. Enabling the tracepoint requires root, but the trigger itself is unprivileged: socket(AF_SMC, ...) has no capability check, and SMC-D negotiation needs no admin step on s390 or on x86 with the loopback ISM device loaded. Log an empty device name for SMC-D instead of dereferencing NULL.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Linux Linux

Default version status: unaffected

  • aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 to < 68200112534bb2acd1d7117dc2d5c124868d866daffected
  • aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 to < 720c76b930c52cd58f50eb6b10569d03dccc7959affected
  • aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 to < b706d6d76a2a2793fe5ad0fbc2a75b6a460094efaffected
  • aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 to < d2ea0b8aef8746e147602eac87ca8538f4bc7e66affected
  • aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 to < 561cf66fa9b6c86dfe4e687d2d1aeaaa6739917faffected
  • aff3083f10bff7a37eaa2b4e6bc5fb627ddd5f84 to < 7bf563badd37cb796df5477d2b78bb64148a1268affected

Linux Linux

Default version status: affected

  • 5.16affected
  • 0 to < 5.16unaffected
  • 6.1.175 to ≤ 6.1.*unaffected
  • 6.6.142 to ≤ 6.6.*unaffected
  • 6.12.92 to ≤ 6.12.*unaffected
  • 6.18.34 to ≤ 6.18.*unaffected
  • 7.0.11 to ≤ 7.0.*unaffected
  • 7.1 to ≤ *unaffected

References