Bug 2535069 (CVE-2026-89784)
| Summary: | CVE-2026-89784 kernel: SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6 | ||
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| Product: | [Other] Security Response | Reporter: | OSIDB Bzimport <bzimport> |
| Component: | vulnerability | Assignee: | Product Security <prodsec-ir-bot> |
| Status: | NEW --- | QA Contact: | |
| Severity: | low | Docs Contact: | |
| Priority: | low | ||
| Version: | unspecified | CC: | akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers |
| Target Milestone: | --- | Keywords: | Security |
| Target Release: | --- | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Whiteboard: | |||
| Fixed In Version: | Doc Type: | --- | |
| Doc Text: |
A flaw was found in the Linux kernel's SUNRPC component. When an in-kernel RPC service registers with the local rpcbind under memory pressure, a failure in memory allocation can lead to a NULL pointer being dereferenced. This unchecked NULL pointer can cause the kernel to crash, resulting in a Denial of Service (DoS).
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Story Points: | --- |
| Clone Of: | Environment: | ||
| Last Closed: | Type: | --- | |
| Regression: | --- | Mount Type: | --- |
| Documentation: | --- | CRM: | |
| Verified Versions: | Category: | --- | |
| oVirt Team: | --- | RHEL 7.3 requirements from Atomic Host: | |
| Cloudforms Team: | --- | Target Upstream Version: | |
| Embargoed: | |||
In the Linux kernel, the following vulnerability has been resolved: SUNRPC: check rpc_sockaddr2uaddr() return value in rpcb_register_inet4/6 rpcb_register_inet4() and rpcb_register_inet6() store the result of rpc_sockaddr2uaddr() into map->r_addr without checking it for NULL. rpc_sockaddr2uaddr() returns NULL when its final kstrdup() fails, and the unchecked NULL is then carried into the synchronous RPCBPROC_SET encode path: rpcb_register_call() -> rpc_call_sync() -> rpcb_enc_getaddr() -> encode_rpcb_string(), whose first statement is strlen(string), dereferencing NULL and oopsing the kernel. The crash reproduces under failslab on v6.12; with KASAN the NULL dereference surfaces as a fault on the shadow of address zero: Oops: general protection fault, probably for non-canonical address 0xdffffc0000000000 [#1] PREEMPT SMP KASAN RIP: 0010:strlen (lib/string.c:409) Call Trace: encode_rpcb_string (net/sunrpc/rpcb_clnt.c:890) rpcb_enc_getaddr (net/sunrpc/rpcb_clnt.c:910) rpcauth_wrap_req_encode (net/sunrpc/auth.c:745) call_encode (net/sunrpc/clnt.c:1966) __rpc_execute (net/sunrpc/sched.c:952) rpc_run_task (net/sunrpc/clnt.c:1243) rpc_call_sync (net/sunrpc/clnt.c:1272) rpcb_v4_register (net/sunrpc/rpcb_clnt.c:500) svc_generic_rpcbind_set nfsd_rpcbind_set svc_register svc_setup_socket svc_addsock write_ports nfsctl_transaction_write vfs_write The crash is reachable when an in-kernel RPC service (nfsd, lockd, nfs-callback) registers with the local rpcbind under enough memory pressure for the small GFP_KERNEL kstrdup() in rpc_sockaddr2uaddr() to fail. The asynchronous getport path already handles this exact failure mode by returning -ENOMEM; only the two register helpers omit the check. Mirror that handling: bail out with -ENOMEM when rpc_sockaddr2uaddr() returns NULL, before the address is fed into the encoder.