hx509: add hx509_certs_destroy()

lib/hx509/file.c

@@ -300,3 +300,90 @@ hx509_pem_read(hx509_context context,
 
     return ret;
 }
+
+/*
+ * On modern systems there's no such thing as scrubbing a file.  Not this way
+ * anyways.  However, for now we'll cargo-cult this along just as in lib/krb5.
+ */
+static int
+scrub_file(int fd, ssize_t sz)
+{
+    char buf[128];
+
+    memset(buf, 0, sizeof(buf));
+    while (sz > 0) {
+        ssize_t tmp;
+        size_t wr = sizeof(buf) > sz ? (size_t)sz : sizeof(buf);
+
+        tmp = write(fd, buf, wr);
+        if (tmp == -1)
+            return errno;
+        sz -= tmp;
+    }
+#ifdef _MSC_VER
+    return _commit(fd);
+#else
+    return fsync(fd);
+#endif
+}
+
+int
+_hx509_erase_file(hx509_context context, const char *fn)
+{
+    struct stat sb1, sb2;
+    int ret;
+    int fd;
+
+    if (fn == NULL)
+        return 0;
+
+    /* This is based on _krb5_erase_file(), minus file locking */
+    ret = lstat(fn, &sb1);
+    if (ret == -1 && errno == ENOENT)
+        return 0;
+    if (ret == -1) {
+        hx509_set_error_string(context, 0, ret, "hx509_certs_destroy: "
+                               "stat of \"%s\": %s", fn, strerror(ret));
+        return errno;
+    }
+
+    fd = open(fn, O_RDWR | O_BINARY | O_CLOEXEC | O_NOFOLLOW);
+    rk_cloexec(fd);
+    if (ret == -1 && errno == ENOENT)
+        return 0;
+    if (ret == -1)
+        return errno;
+
+    if (unlink(fn) < 0) {
+	ret = errno;
+        (void) close(fd);
+        hx509_set_error_string(context, 0, ret, "hx509_certs_destroy: "
+                               "unlinking \"%s\": %s", fn, strerror(ret));
+        return ret;
+    }
+
+    /* check TOCTOU, symlinks */
+    ret = fstat(fd, &sb2);
+    if (ret < 0) {
+	ret = errno;
+        hx509_set_error_string(context, 0, ret, "hx509_certs_destroy: "
+                               "fstat of %d, \"%s\": %s", fd, fn,
+                               strerror(ret));
+	(void) close(fd);
+	return ret;
+    }
+    if (sb1.st_dev != sb2.st_dev || sb1.st_ino != sb2.st_ino) {
+	(void) close(fd);
+	return EPERM;
+    }
+
+    /* there are still hard links to this file */
+    if (sb2.st_nlink != 0) {
+        close(fd);
+        return 0;
+    }
+
+    ret = scrub_file(fd, sb2.st_size);
+    (void) close(fd);
+    return ret;
+}

lib/hx509/hx_locl.h

@@ -70,6 +70,13 @@
 
 #include <der.h>
 
+#ifndef O_CLOEXEC
+#define O_CLOEXEC 0
+#endif
+#ifndef O_BINARY
+#define O_BINARY 0
+#endif
+
 /*
  * We use OpenSSL for EC, but to do this we need to disable cross-references
  * between OpenSSL and hcrypto bn.h and such.  Source files that use OpenSSL EC
@@ -180,6 +187,7 @@ struct hx509_keyset_ops {
 		     void *, int (*)(void *, const char *), void *);
     int (*getkeys)(hx509_context, hx509_certs, void *, hx509_private_key **);
     int (*addkey)(hx509_context, hx509_certs, void *, hx509_private_key);
+    int (*destroy)(hx509_context, hx509_certs, void *);
 };
 
 struct _hx509_password {

lib/hx509/keyset.c

@@ -168,6 +168,33 @@ hx509_certs_init(hx509_context context,
     return 0;
 }
 
+/**
+ * Destroys and frees a hx509 certificate store.
+ *
+ * @param context A hx509 context
+ * @param certs A store to destroy
+ *
+ * @return Returns an hx509 error code.
+ *
+ * @ingroup hx509_keyset
+ */
+
+HX509_LIB_FUNCTION int HX509_LIB_CALL
+hx509_certs_destroy(hx509_context context,
+                    hx509_certs *certs)
+{
+    int ret = 0;
+
+    if (*certs) {
+        if ((*certs)->ops->destroy)
+            ret = ((*certs)->ops->destroy)(context, *certs, (*certs)->ops_data);
+        else
+            ret = ENOTSUP;
+    }
+    hx509_certs_free(certs);
+    return ret;
+}
+
 /**
  * Write the certificate store to stable storage.
  *

lib/hx509/ks_dir.c

@@ -220,6 +220,7 @@ static struct hx509_keyset_ops keyset_dir = {
     dir_iter_end,
     NULL,
     NULL,
+    NULL,
     NULL
 };
 

lib/hx509/ks_file.c

@@ -664,6 +664,15 @@ file_addkey(hx509_context context,
     return _hx509_certs_keys_add(context, ksf->certs, key);
 }
 
+static int
+file_destroy(hx509_context context,
+             hx509_certs certs,
+             void *data)
+{
+    struct ks_file *ksf = data;
+    return _hx509_erase_file(context, ksf->fn);
+}
+
 static struct hx509_keyset_ops keyset_file = {
     "FILE",
     0,
@@ -677,7 +686,8 @@ static struct hx509_keyset_ops keyset_file = {
     file_iter_end,
     NULL,
     file_getkeys,
-    file_addkey
+    file_addkey,
+    file_destroy
 };
 
 static struct hx509_keyset_ops keyset_pemfile = {
@@ -693,7 +703,8 @@ static struct hx509_keyset_ops keyset_pemfile = {
     file_iter_end,
     NULL,
     file_getkeys,
-    file_addkey
+    file_addkey,
+    file_destroy
 };
 
 static struct hx509_keyset_ops keyset_derfile = {
@@ -709,7 +720,8 @@ static struct hx509_keyset_ops keyset_derfile = {
     file_iter_end,
     NULL,
     file_getkeys,
-    file_addkey
+    file_addkey,
+    file_destroy
 };
 
 

lib/hx509/ks_keychain.c

@@ -599,6 +599,7 @@ struct hx509_keyset_ops keyset_keychain = {
     keychain_iter_end,
     NULL,
     NULL,
+    NULL,
     NULL
 };
 

lib/hx509/ks_mem.c

@@ -213,7 +213,8 @@ static struct hx509_keyset_ops keyset_mem = {
     mem_iter_end,
     NULL,
     mem_getkeys,
-    mem_addkey
+    mem_addkey,
+    NULL
 };
 
 HX509_LIB_FUNCTION void HX509_LIB_CALL

lib/hx509/ks_null.c

@@ -90,6 +90,7 @@ struct hx509_keyset_ops keyset_null = {
     null_iter_end,
     NULL,
     NULL,
+    NULL,
     NULL
 };
 

lib/hx509/ks_p11.c

@@ -1208,6 +1208,7 @@ static struct hx509_keyset_ops keyset_pkcs11 = {
     p11_iter_end,
     p11_printinfo,
     NULL,
+    NULL,
     NULL
 };
 

lib/hx509/ks_p12.c

@@ -697,6 +697,13 @@ p12_iter_end(hx509_context context,
     return hx509_certs_end_seq(context, p12->certs, cursor);
 }
 
+static int
+p12_destroy(hx509_context context, hx509_certs certs, void *data)
+{
+    struct ks_pkcs12 *p12 = data;
+    return _hx509_erase_file(context, p12->fn);
+}
+
 static struct hx509_keyset_ops keyset_pkcs12 = {
     "PKCS12",
     0,
@@ -710,7 +717,8 @@ static struct hx509_keyset_ops keyset_pkcs12 = {
     p12_iter_end,
     NULL,
     NULL,
-    NULL
+    NULL,
+    p12_destroy
 };
 
 HX509_LIB_FUNCTION void HX509_LIB_CALL

lib/hx509/libhx509-exports.def

@@ -92,6 +92,7 @@ EXPORTS
 	hx509_cert_set_friendly_name
 	hx509_certs_add
 	hx509_certs_append
+	hx509_certs_destroy
 	hx509_certs_end_seq
 	hx509_certs_ref
 	hx509_certs_filter

lib/hx509/version-script.map

@@ -88,6 +88,7 @@ HEIMDAL_X509_1.2 {
 		hx509_certs_add;
 		hx509_certs_append;
 		hx509_certs_end_seq;
+		hx509_certs_destroy;
 		hx509_certs_ref;
 		hx509_certs_filter;
 		hx509_certs_find;