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authorDavid Disseldorp2023-04-13 23:49:57 +0900
committerSteve French2023-04-13 14:17:32 -0500
commite7067a446264a7514fa1cfaa4052cdb6803bc6a2 (patch)
treeb4600382146430cdb6cc340d2244f4f8541e604e /fs/ksmbd
parent09a9639e56c01c7a00d6c0ca63f4c7c41abe075d (diff)
ksmbd: avoid out of bounds access in decode_preauth_ctxt()
Confirm that the accessed pneg_ctxt->HashAlgorithms address sits within the SMB request boundary; deassemble_neg_contexts() only checks that the eight byte smb2_neg_context header + (client controlled) DataLength are within the packet boundary, which is insufficient. Checking for sizeof(struct smb2_preauth_neg_context) is overkill given that the type currently assumes SMB311_SALT_SIZE bytes of trailing Salt. Signed-off-by: David Disseldorp <ddiss@suse.de> Acked-by: Namjae Jeon <linkinjeon@kernel.org> Cc: <stable@vger.kernel.org> Signed-off-by: Steve French <stfrench@microsoft.com>
Diffstat (limited to 'fs/ksmbd')
-rw-r--r--fs/ksmbd/smb2pdu.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
index 8af939a181be..67b7e766a06b 100644
--- a/fs/ksmbd/smb2pdu.c
+++ b/fs/ksmbd/smb2pdu.c
@@ -876,17 +876,21 @@ static void assemble_neg_contexts(struct ksmbd_conn *conn,
}
static __le32 decode_preauth_ctxt(struct ksmbd_conn *conn,
- struct smb2_preauth_neg_context *pneg_ctxt)
+ struct smb2_preauth_neg_context *pneg_ctxt,
+ int len_of_ctxts)
{
- __le32 err = STATUS_NO_PREAUTH_INTEGRITY_HASH_OVERLAP;
+ /*
+ * sizeof(smb2_preauth_neg_context) assumes SMB311_SALT_SIZE Salt,
+ * which may not be present. Only check for used HashAlgorithms[1].
+ */
+ if (len_of_ctxts < MIN_PREAUTH_CTXT_DATA_LEN)
+ return STATUS_INVALID_PARAMETER;
- if (pneg_ctxt->HashAlgorithms == SMB2_PREAUTH_INTEGRITY_SHA512) {
- conn->preauth_info->Preauth_HashId =
- SMB2_PREAUTH_INTEGRITY_SHA512;
- err = STATUS_SUCCESS;
- }
+ if (pneg_ctxt->HashAlgorithms != SMB2_PREAUTH_INTEGRITY_SHA512)
+ return STATUS_NO_PREAUTH_INTEGRITY_HASH_OVERLAP;
- return err;
+ conn->preauth_info->Preauth_HashId = SMB2_PREAUTH_INTEGRITY_SHA512;
+ return STATUS_SUCCESS;
}
static void decode_encrypt_ctxt(struct ksmbd_conn *conn,
@@ -1014,7 +1018,8 @@ static __le32 deassemble_neg_contexts(struct ksmbd_conn *conn,
break;
status = decode_preauth_ctxt(conn,
- (struct smb2_preauth_neg_context *)pctx);
+ (struct smb2_preauth_neg_context *)pctx,
+ len_of_ctxts);
if (status != STATUS_SUCCESS)
break;
} else if (pctx->ContextType == SMB2_ENCRYPTION_CAPABILITIES) {