From 6668ed271eaefaa63e686bdfbedaeb7b8e492722 Mon Sep 17 00:00:00 2001 From: Kumar Kartikeya Dwivedi Date: Fri, 4 Sep 2026 10:43:19 +0200 Subject: selftests/bpf: Reject graph kptr use after RCU unlock Add a sleepable verifier test that loads a graph-node local kptr in an explicit RCU read-side critical section, then passes its node to bpf_rbtree_remove() after the section ends. Before the verifier fix, the stale NON_OWN_REF flag makes the node look like a live borrowed reference and the program is accepted. After the fix, the pointer is demoted without NON_OWN_REF and the graph kfunc argument is rejected. Also exercise a graph kptr loaded while a spin lock provides implicit RCU protection. The pointer must be invalidated when the lock is released, which guards the required ordering between non-owning-reference invalidation and RCU demotion. Update the existing fault-protected load test state description. The post-unlock pointer no longer carries NON_OWN_REF, but remains readable because the load is rewritten to use BPF_PROBE_MEM. Signed-off-by: Kumar Kartikeya Dwivedi Link: https://lore.kernel.org/r/20260904084325.52250-7-memxor@gmail.com Signed-off-by: Alexei Starovoitov --- fs/smb/client/smb1encrypt.c | 140 ++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 140 insertions(+) create mode 100644 fs/smb/client/smb1encrypt.c (limited to 'fs/smb/client/smb1encrypt.c') diff --git a/fs/smb/client/smb1encrypt.c b/fs/smb/client/smb1encrypt.c new file mode 100644 index 000000000..bf10fdeee --- /dev/null +++ b/fs/smb/client/smb1encrypt.c @@ -0,0 +1,140 @@ +// SPDX-License-Identifier: LGPL-2.1 +/* + * + * Encryption and hashing operations relating to NTLM, NTLMv2. See MS-NLMP + * for more detailed information + * + * Copyright (C) International Business Machines Corp., 2005,2013 + * Author(s): Steve French (sfrench@us.ibm.com) + * + */ + +#include +#include +#include +#include "cifsproto.h" +#include "smb1proto.h" +#include "cifs_debug.h" + +/* + * Calculate and return the CIFS signature based on the mac key and SMB PDU. + * The 16 byte signature must be allocated by the caller. Note we only use the + * 1st eight bytes and that the smb header signature field on input contains + * the sequence number before this function is called. Also, this function + * should be called with the server->srv_mutex held. + */ +static int cifs_calc_signature(struct smb_rqst *rqst, + struct TCP_Server_Info *server, char *signature) +{ + struct md5_ctx ctx; + + if (!rqst->rq_iov || !signature || !server) + return -EINVAL; + if (fips_enabled) { + cifs_dbg(VFS, + "MD5 signature support is disabled due to FIPS\n"); + return -EOPNOTSUPP; + } + + md5_init(&ctx); + md5_update(&ctx, server->session_key.response, server->session_key.len); + + return __cifs_calc_signature( + rqst, server, signature, + &(struct cifs_calc_sig_ctx){ .md5 = &ctx }); +} + +/* must be called with server->srv_mutex held */ +int cifs_sign_rqst(struct smb_rqst *rqst, struct TCP_Server_Info *server, + __u32 *pexpected_response_sequence_number) +{ + int rc = 0; + char smb_signature[20]; + struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base; + + if ((cifs_pdu == NULL) || (server == NULL)) + return -EINVAL; + + spin_lock(&server->srv_lock); + if (!(cifs_pdu->Flags2 & SMBFLG2_SECURITY_SIGNATURE) || + server->tcpStatus == CifsNeedNegotiate) { + spin_unlock(&server->srv_lock); + return rc; + } + spin_unlock(&server->srv_lock); + + if (!server->session_estab) { + memcpy(cifs_pdu->Signature.SecuritySignature, "BSRSPYL", 8); + return rc; + } + + cifs_pdu->Signature.Sequence.SequenceNumber = + cpu_to_le32(server->sequence_number); + cifs_pdu->Signature.Sequence.Reserved = 0; + + *pexpected_response_sequence_number = ++server->sequence_number; + ++server->sequence_number; + + rc = cifs_calc_signature(rqst, server, smb_signature); + if (rc) + memset(cifs_pdu->Signature.SecuritySignature, 0, 8); + else + memcpy(cifs_pdu->Signature.SecuritySignature, smb_signature, 8); + + return rc; +} + +int cifs_verify_signature(struct smb_rqst *rqst, + struct TCP_Server_Info *server, + __u32 expected_sequence_number) +{ + unsigned int rc; + char server_response_sig[8]; + char what_we_think_sig_should_be[20]; + struct smb_hdr *cifs_pdu = (struct smb_hdr *)rqst->rq_iov[0].iov_base; + + if (cifs_pdu == NULL || server == NULL) + return -EINVAL; + + if (!server->session_estab) + return 0; + + if (cifs_pdu->Command == SMB_COM_LOCKING_ANDX) { + struct smb_com_lock_req *pSMB = + (struct smb_com_lock_req *)cifs_pdu; + if (pSMB->LockType & LOCKING_ANDX_OPLOCK_RELEASE) + return 0; + } + + /* BB what if signatures are supposed to be on for session but + server does not send one? BB */ + + /* Do not need to verify session setups with signature "BSRSPYL " */ + if (memcmp(cifs_pdu->Signature.SecuritySignature, "BSRSPYL ", 8) == 0) + cifs_dbg(FYI, "dummy signature received for smb command 0x%x\n", + cifs_pdu->Command); + + /* save off the original signature so we can modify the smb and check + its signature against what the server sent */ + memcpy(server_response_sig, cifs_pdu->Signature.SecuritySignature, 8); + + cifs_pdu->Signature.Sequence.SequenceNumber = + cpu_to_le32(expected_sequence_number); + cifs_pdu->Signature.Sequence.Reserved = 0; + + cifs_server_lock(server); + rc = cifs_calc_signature(rqst, server, what_we_think_sig_should_be); + cifs_server_unlock(server); + + if (rc) + return rc; + +/* cifs_dump_mem("what we think it should be: ", + what_we_think_sig_should_be, 16); */ + + if (crypto_memneq(server_response_sig, what_we_think_sig_should_be, 8)) + return -EACCES; + else + return 0; + +} -- cgit v1.3.1