commit 309a220194fd4b49df6f42db0b89b84054458b46
author Martijn Coenen <maco@google.com> Mon Mar 15 23:45:07 2021 +0100
committer Martijn Coenen <maco@google.com> Tue Mar 16 00:15:44 2021 +0100
tree dd64aee4b0bc2fe88bdada3dcee22e77c1d2bf2a
parent 430de6f5d3dcf069b81d4f575c1470f92559573b

On-device signing: some more error checking.

Handle error conditions while computing a digest for a file, and fix a
memory leak.

Bug: 165630556
Test: boots
Change-Id: Iab73486c2fad5d54adb9b983b74dd697f7063c38

ondevice-signing/VerityUtils.cpp

diff --git a/ondevice-signing/VerityUtils.cpp b/ondevice-signing/VerityUtils.cpp
index ff7de7e..cab92e2 100644
--- a/ondevice-signing/VerityUtils.cpp
+++ b/ondevice-signing/VerityUtils.cpp
@@ -74,8 +74,14 @@
 Result<std::vector<uint8_t>> createDigest(const std::string& path) {
     struct stat filestat;
     unique_fd fd(TEMP_FAILURE_RETRY(open(path.c_str(), O_RDONLY | O_CLOEXEC)));
+    if (fd < 0) {
+        return ErrnoError() << "Failed to open " << path;
+    }
 
-    stat(path.c_str(), &filestat);
+    int ret = stat(path.c_str(), &filestat);
+    if (ret < 0) {
+        return ErrnoError() << "Failed to stat " << path;
+    }
     struct libfsverity_merkle_tree_params params = {
         .version = 1,
         .hash_algorithm = FS_VERITY_HASH_ALG_SHA256,
@@ -84,9 +90,13 @@
     };
 
     struct libfsverity_digest* digest;
-    libfsverity_compute_digest(&fd, &read_callback, &params, &digest);
-
-    return std::vector<uint8_t>(&digest->digest[0], &digest->digest[32]);
+    ret = libfsverity_compute_digest(&fd, &read_callback, &params, &digest);
+    if (ret < 0) {
+        return ErrnoError() << "Failed to compute fs-verity digest for " << path;
+    }
+    std::vector<uint8_t> digestVector(&digest->digest[0], &digest->digest[32]);
+    free(digest);
+    return digestVector;
 }
 
 namespace {