fix: harden store writes, strict schemas, null cfg

src/config/sources.ts

@@ -36,6 +36,12 @@ export const readConfigFile = (path: string | undefined): ConnectionConfig[] =>
         console.error('dbmole: config file ' + path + ' is not valid JSON, ignoring')
         return []
     }
+    if (typeof parsed !== 'object' || parsed === null || Array.isArray(parsed)) {
+        console.error(
+            'dbmole: config file ' + path + ' must contain { "connections": [...] }, ignoring'
+        )
+        return []
+    }
     const connections = (parsed as { connections?: unknown }).connections
     if (!Array.isArray(connections)) {
         console.error(

src/config/store.ts

@@ -1,4 +1,4 @@
-import { existsSync, mkdirSync, readFileSync, renameSync, writeFileSync } from 'node:fs'
+import { existsSync, mkdirSync, readFileSync, renameSync, rmSync, writeFileSync } from 'node:fs'
 import { homedir } from 'node:os'
 import { dirname, join } from 'node:path'
 import { type ConnectionConfig, connectionConfigSchema } from './types.js'
@@ -47,10 +47,25 @@ let writeSeq = 0
 
 export const writeStore = (path: string, connections: ConnectionConfig[]): void => {
     mkdirSync(dirname(path), { recursive: true, mode: 0o700 })
-    writeSeq += 1
-    const tmp = path + '.' + process.pid + '.' + writeSeq + '.tmp'
     const items = connections.map((c) => JSON.stringify(c, null, 4))
     const content = items.length === 0 ? '[]\n' : '[\n' + items.join(',\n') + '\n]\n'
-    writeFileSync(tmp, content, { mode: 0o600 })
-    renameSync(tmp, path)
+    let tmp: string
+    for (;;) {
+        writeSeq += 1
+        tmp = path + '.' + process.pid + '.' + writeSeq + '.tmp'
+        try {
+            writeFileSync(tmp, content, { mode: 0o600, flag: 'wx' })
+            break
+        } catch (error) {
+            if ((error as NodeJS.ErrnoException).code !== 'EEXIST') {
+                throw error
+            }
+        }
+    }
+    try {
+        renameSync(tmp, path)
+    } catch (error) {
+        rmSync(tmp, { force: true })
+        throw error
+    }
 }

src/config/types.ts

@@ -1,27 +1,31 @@
 import * as z from 'zod'
 
-export const sshConfigSchema = z.object({
-    host: z.string().min(1),
-    port: z.number().int().positive().default(22),
-    user: z.string().min(1),
-    password: z.string().optional(),
-    privateKey: z.string().optional(),
-    privateKeyPath: z.string().optional(),
-    passphrase: z.string().optional(),
-    agent: z.boolean().optional()
-})
+export const sshConfigSchema = z
+    .object({
+        host: z.string().min(1),
+        port: z.number().int().positive().default(22),
+        user: z.string().min(1),
+        password: z.string().optional(),
+        privateKey: z.string().optional(),
+        privateKeyPath: z.string().optional(),
+        passphrase: z.string().optional(),
+        agent: z.boolean().optional()
+    })
+    .strict()
 
-export const connectionConfigSchema = z.object({
-    name: z.string().regex(/^[a-zA-Z0-9_-]+$/, 'name must match [a-zA-Z0-9_-]+'),
-    type: z.enum(['postgres', 'mysql']),
-    host: z.string().min(1),
-    port: z.number().int().positive().optional(),
-    user: z.string().min(1),
-    password: z.string().optional(),
-    database: z.string().optional(),
-    readonly: z.boolean().default(false),
-    ssh: sshConfigSchema.optional()
-})
+export const connectionConfigSchema = z
+    .object({
+        name: z.string().regex(/^[a-zA-Z0-9_-]+$/, 'name must match [a-zA-Z0-9_-]+'),
+        type: z.enum(['postgres', 'mysql']),
+        host: z.string().min(1),
+        port: z.number().int().positive().optional(),
+        user: z.string().min(1),
+        password: z.string().optional(),
+        database: z.string().optional(),
+        readonly: z.boolean().default(false),
+        ssh: sshConfigSchema.optional()
+    })
+    .strict()
 
 export type SshConfig = z.infer<typeof sshConfigSchema>
 export type ConnectionConfig = z.infer<typeof connectionConfigSchema>