fixup! Single-process-lifetime rollback protection for protected files (WIP)

Signed-off-by: g2flyer <[email protected]>

Author: g2flyer

libos/include/libos_fs_encrypted.h

@@ -202,6 +202,7 @@ int encrypted_file_read(struct libos_encrypted_file* enc, void* buf, size_t buf_
 int encrypted_file_write(struct libos_encrypted_file* enc, const void* buf, size_t buf_size,
                          file_off_t offset, size_t* out_count);
 int encrypted_file_rename(struct libos_encrypted_file* enc, const char* new_uri);
+int encrypted_file_unlink(struct libos_encrypted_file* enc);
 
 int encrypted_file_get_size(struct libos_encrypted_file* enc, file_off_t* out_size);
 int encrypted_file_set_size(struct libos_encrypted_file* enc, file_off_t size);

libos/src/fs/chroot/encrypted.c

@@ -338,6 +338,13 @@ static int chroot_encrypted_unlink(struct libos_dentry* dent) {
     if (ret < 0)
         return ret;
 
+    struct libos_encrypted_file* enc = dent->inode->data;
+    if (!enc)
+        return -EACCES;
+    ret = encrypted_file_unlink(enc);
+    if (ret < 0)
+        return ret;
+
     PAL_HANDLE palhdl;
     ret = PalStreamOpen(uri, PAL_ACCESS_RDONLY, /*share_flags=*/0, PAL_CREATE_NEVER,
                         PAL_OPTION_PASSTHROUGH, &palhdl);

libos/src/fs/libos_fs_encrypted.c

@@ -300,8 +300,13 @@ static void encrypted_file_internal_close(struct libos_encrypted_file* enc) {
         file_state->state = PF_FILE_ERROR;
         pf_set_corrupted(enc->pf);
     } else {
-        memcpy(file_state->last_seen_root_gmac, closing_root_gmac, sizeof(pf_mac_t));
-        file_state->state = PF_FILE_CLOSED;
+        // TODO (MST): Below also has to rule out that our file is stale, i.e., somebody has renamed
+        // a file to our own original file name
+        if (file_state->state != PF_FILE_DELETED) {
+            // TODO (MST): omit below if read-only file?
+            memcpy(file_state->last_seen_root_gmac, closing_root_gmac, sizeof(pf_mac_t));
+            file_state->state = PF_FILE_CLOSED;
+        }
     }
     unlock(&(enc->volume->files_state_map_lock));
 
@@ -768,8 +773,8 @@ int encrypted_file_rename(struct libos_encrypted_file* enc, const char* new_uri)
         HASH_ADD_KEYPTR(hh, enc->volume->files_state_map, new_file_state->norm_path,
                         strlen(new_file_state->norm_path), new_file_state);
     } else {
-        free(new_file_state->norm_path);  // should be same but free old one to simplify below
-        new_file_state->norm_path = new_norm_path;
+        free(new_norm_path);  // should be same as old one used during HASH_ADD
+        new_norm_path = new_file_state->norm_path;
     }
     new_file_state->state = old_file_state->state;
     memcpy(new_file_state->last_seen_root_gmac, new_root_gmac, sizeof(pf_mac_t));
@@ -803,6 +808,21 @@ int encrypted_file_rename(struct libos_encrypted_file* enc, const char* new_uri)
     return ret;
 }
 
+int encrypted_file_unlink(struct libos_encrypted_file* enc) {
+    lock(&(enc->volume->files_state_map_lock));
+    struct libos_encrypted_volume_state_map* file_state = NULL;
+    HASH_FIND_STR(enc->volume->files_state_map, enc->norm_path, file_state);
+    assert(file_state != NULL);
+    pf_mac_t root_gmac_before_unlink;
+    memcpy(root_gmac_before_unlink, file_state->last_seen_root_gmac, sizeof(pf_mac_t));
+    file_state->state = PF_FILE_DELETED;
+    memset(file_state->last_seen_root_gmac, 0, sizeof(pf_mac_t));
+    unlock(&(enc->volume->files_state_map_lock));
+    log_debug("file '%s' unlinked, previously with MAC=" MAC_PRINTF_PATTERN, enc->norm_path,
+              MAC_PRINTF_ARGS(root_gmac_before_unlink));  // TODO (MST): remove me eventually?
+    return 0;
+}
+
 /* Checkpoint the `g_keys` list. */
 BEGIN_CP_FUNC(all_encrypted_files_keys) {
     __UNUSED(size);

libos/test/regression/rename_unlink

@@ -0,0 +1 @@
+../../../build/libos/test/regression/rename_unlink