Merge bitcoin/bitcoin#23213: rest: Return error when header count is not integral

fa8d49289479b8eda7ba7530515c414d1cd566a3 rest: Return error when header count is not integral (MarcoFalke)

Pull request description:

  Seems odd to interpret a hash (or any other string) as integer when it contains more than the digits 0 to 9.

ACKs for top commit:
  practicalswift:
    cr ACK fa8d49289479b8eda7ba7530515c414d1cd566a3
  promag:
    Code review ACK fa8d49289479b8eda7ba7530515c414d1cd566a3.
  shaavan:
    Code Review ACK fa8d49289479b8eda7ba7530515c414d1cd566a3

Tree-SHA512: d6335b132ca2010fb8cae311dd936b2dea99a5bd0e6b2556a604f93698b8456df9190c5151345a03344243ede4aad0e2526cedc2aa8b5b1b8e8ce786cb3b6e50

3 files changed, 14 insertions, 6 deletions

diff --git a/src/rest.cpp b/src/rest.cpp
index e50ab33e54..f6e34c2d81 100644
--- a/src/rest.cpp
+++ b/src/rest.cpp
@@ -189,9 +189,10 @@ static bool rest_headers(const std::any& context,
     if (path.size() != 2)
         return RESTERR(req, HTTP_BAD_REQUEST, "No header count specified. Use /rest/headers/<count>/<hash>.<ext>.");
 
-    long count = strtol(path[0].c_str(), nullptr, 10);
-    if (count < 1 || count > 2000)
+    const auto parsed_count{ToIntegral<size_t>(path[0])};
+    if (!parsed_count.has_value() || *parsed_count < 1 || *parsed_count > 2000) {
         return RESTERR(req, HTTP_BAD_REQUEST, "Header count out of range: " + path[0]);
+    }
 
     std::string hashStr = path[1];
     uint256 hash;
@@ -199,8 +200,8 @@ static bool rest_headers(const std::any& context,
         return RESTERR(req, HTTP_BAD_REQUEST, "Invalid hash: " + hashStr);
 
     const CBlockIndex* tip = nullptr;
-    std::vector<const CBlockIndex *> headers;
-    headers.reserve(count);
+    std::vector<const CBlockIndex*> headers;
+    headers.reserve(*parsed_count);
     {
         ChainstateManager* maybe_chainman = GetChainman(context, req);
         if (!maybe_chainman) return false;
@@ -211,8 +212,9 @@ static bool rest_headers(const std::any& context,
         const CBlockIndex* pindex = chainman.m_blockman.LookupBlockIndex(hash);
         while (pindex != nullptr && active_chain.Contains(pindex)) {
             headers.push_back(pindex);
-            if (headers.size() == (unsigned long)count)
+            if (headers.size() == *parsed_count) {
                 break;
+            }
             pindex = active_chain.Next(pindex);
         }
     }
diff --git a/test/functional/interface_rest.py b/test/functional/interface_rest.py
index e0716fc54a..adc33bd9df 100755
--- a/test/functional/interface_rest.py
+++ b/test/functional/interface_rest.py
@@ -279,6 +279,13 @@ class RESTTest (BitcoinTestFramework):
         json_obj = self.test_rest_request(f"/headers/5/{bb_hash}")
         assert_equal(len(json_obj), 5)  # now we should have 5 header objects
 
+        # Test number parsing
+        for num in ['5a', '-5', '0', '2001', '99999999999999999999999999999999999']:
+            assert_equal(
+                bytes(f'Header count out of range: {num}\r\n', 'ascii'),
+                self.test_rest_request(f"/headers/{num}/{bb_hash}", ret_type=RetType.BYTES, status=400),
+            )
+
         self.log.info("Test tx inclusion in the /mempool and /block URIs")
 
         # Make 3 tx and mine them on node 1
diff --git a/test/lint/lint-locale-dependence.sh b/test/lint/lint-locale-dependence.sh
index f82d82f890..34022ece35 100755
--- a/test/lint/lint-locale-dependence.sh
+++ b/test/lint/lint-locale-dependence.sh
@@ -43,7 +43,6 @@ export LC_ALL=C
 KNOWN_VIOLATIONS=(
     "src/bitcoin-tx.cpp.*stoul"
     "src/dbwrapper.cpp:.*vsnprintf"
-    "src/rest.cpp:.*strtol"
     "src/test/dbwrapper_tests.cpp:.*snprintf"
     "src/test/fuzz/locale.cpp"
     "src/test/fuzz/string.cpp"