Fix for large file transfers on client side with SFTP

.github/workflows/sshd-test.yml

@@ -22,7 +22,7 @@ jobs:
     - name: autogen
       run: ./autogen.sh
     - name: configure
-      run: ./configure --enable-all CPPFLAGS=-DWOLFSSH_NO_FPKI
+      run: ./configure --enable-all CPPFLAGS="-DWOLFSSH_NO_FPKI -DWOLFSSH_NO_SFTP_TIMEOUT -DWOLFSSH_MAX_SFTP_RW=4000000"
     - name: make
       run: make
     - name: make check

apps/wolfsshd/test/run_all_sshd_tests.sh

@@ -59,6 +59,7 @@ run_test() {
 
 run_test "sshd_exec_test.sh"
 run_test "sshd_term_size_test.sh"
+run_test "sshd_large_sftp_test.sh"
 
 #Github actions needs resolved for these test cases
 #run_test "error_return.sh"

apps/wolfsshd/test/sshd_large_sftp_test.sh

@@ -0,0 +1,40 @@
+#!/bin/sh
+
+# sshd local test
+
+PWD=`pwd`
+cd ../../..
+
+TEST_SFTP_CLIENT="./examples/sftpclient/wolfsftp"
+USER=`whoami`
+PRIVATE_KEY="./keys/hansel-key-ecc.der"
+PUBLIC_KEY="./keys/hansel-key-ecc.pub"
+
+if [ -z "$1" ] || [ -z "$2" ]; then
+    echo "expecting host and port as arguments"
+    echo "./sshd_exec_test.sh 127.0.0.1 22222"
+    exit 1
+fi
+
+
+# create a large file with random data (larger than word32 max value)
+head -c 4400000010 < /dev/random > large-random.txt
+
+set -e
+echo "$TEST_SFTP_CLIENT -u $USER -i $PRIVATE_KEY -j $PUBLIC_KEY -g -l large-random.txt -r `pwd`/large-random-2.txt -h \"$1\" -p \"$2\""
+$TEST_SFTP_CLIENT -u $USER -i $PRIVATE_KEY -j $PUBLIC_KEY -g -l large-random.txt -r `pwd`/large-random-2.txt -h "$1" -p "$2"
+
+cmp large-random.txt large-random-2.txt
+RESULT=$?
+if [ "$RESULT" != "0" ]; then
+    echo "files did not match when compared"
+    exit 1
+fi
+rm -f large-random.txt
+rm -f large-random-2.txt
+
+set +e
+
+cd $PWD
+exit 0
+

src/internal.c

@@ -14379,7 +14379,9 @@ void AddAssign64(word32* addend1, word32 addend2)
 {
     if (addend1[0] > (WOLFSSL_MAX_32BIT - addend2)) {
         addend1[1]++;
-        addend1[0] = addend2 - (WOLFSSL_MAX_32BIT- addend1[0]);
+
+        /* -1 to account for roll over digit */
+        addend1[0] = addend2 - (WOLFSSL_MAX_32BIT- addend1[0]) - 1;
     }
     else {
         addend1[0] += addend2;