1 files changed, 9 insertions, 6 deletions

diff --git a/src/device/device_ledger.cpp b/src/device/device_ledger.cpp
index 6f2bcf37f..f7bf58531 100644
--- a/src/device/device_ledger.cpp
+++ b/src/device/device_ledger.cpp
@@ -187,14 +187,15 @@ namespace hw {
     void device_ledger::logCMD() {
       if (apdu_verbose) {
         char  strbuffer[1024];
-        sprintf(strbuffer, "%.02x %.02x %.02x %.02x %.02x ",
+        snprintf(strbuffer, sizeof(strbuffer), "%.02x %.02x %.02x %.02x %.02x ",
           this->buffer_send[0],
           this->buffer_send[1],
           this->buffer_send[2],
           this->buffer_send[3],
           this->buffer_send[4]
           );
-        buffer_to_str(strbuffer+strlen(strbuffer), sizeof(strbuffer), (char*)(this->buffer_send+5), this->length_send-5);
+        const size_t len = strlen(strbuffer);
+        buffer_to_str(strbuffer+len, sizeof(strbuffer)-len, (char*)(this->buffer_send+5), this->length_send-5);
         MDEBUG( "CMD  :" << strbuffer);
       }
     }
@@ -202,11 +203,12 @@ namespace hw {
     void device_ledger::logRESP() {
       if (apdu_verbose) {
         char  strbuffer[1024];
-        sprintf(strbuffer, "%.02x%.02x ",
+        snprintf(strbuffer, sizeof(strbuffer), "%.02x%.02x ",
           this->buffer_recv[this->length_recv-2],
           this->buffer_recv[this->length_recv-1]
           );
-        buffer_to_str(strbuffer+strlen(strbuffer), sizeof(strbuffer), (char*)(this->buffer_recv), this->length_recv-2);
+        const size_t len = strlen(strbuffer);
+        buffer_to_str(strbuffer+len, sizeof(strbuffer)-len, (char*)(this->buffer_recv), this->length_recv-2);
         MDEBUG( "RESP :" << strbuffer);
 
       }
@@ -303,7 +305,7 @@ namespace hw {
      
     unsigned int device_ledger::exchange(unsigned int ok, unsigned int mask) {
       LONG rv;
-      int sw;
+      unsigned int sw;
 
       ASSERT_T0(this->length_send <= BUFFER_SEND_SIZE);
       logCMD();
@@ -312,6 +314,7 @@ namespace hw {
                          SCARD_PCI_T0, this->buffer_send, this->length_send,
                          NULL,         this->buffer_recv, &this->length_recv);
       ASSERT_RV(rv);
+      ASSERT_T0(this->length_recv >= 2);
       ASSERT_T0(this->length_recv <= BUFFER_RECV_SIZE);
       logRESP();
 
@@ -415,7 +418,7 @@ namespace hw {
         }
       }
 
-      if (mszReaders) {
+      if (rv == SCARD_S_SUCCESS && mszReaders) {
         #ifdef SCARD_AUTOALLOCATE
         SCardFreeMemory(this->hContext, mszReaders);
         #else