From e2e1fe5aad50809f00f6f5258432bd7aa605f47c Mon Sep 17 00:00:00 2001
From: Dean Camera <dean@fourwalledcubicle.com>
Date: Thu, 15 Jul 2010 04:45:31 +0000
Subject: [PATCH] Fixed possible buffer overrun in the XPLAINBridge project
when in serial bridge mode.
---
Projects/Benito/Lib/LightweightRingBuff.h | 20 +++++++++++++++++++
.../USBtoSerial/Lib/LightweightRingBuff.h | 20 +++++++++++++++++++
Projects/USBtoSerial/USBtoSerial.c | 2 +-
.../XPLAINBridge/Lib/LightweightRingBuff.h | 20 +++++++++++++++++++
Projects/XPLAINBridge/XPLAINBridge.c | 2 +-
5 files changed, 62 insertions(+), 2 deletions(-)
diff --git a/Projects/Benito/Lib/LightweightRingBuff.h b/Projects/Benito/Lib/LightweightRingBuff.h
index 9c25707b4..0ffe792dc 100644
--- a/Projects/Benito/Lib/LightweightRingBuff.h
+++ b/Projects/Benito/Lib/LightweightRingBuff.h
@@ -75,6 +75,26 @@
Buffer->Count = 0;
}
+ /** Atomically determines if the specified ring buffer contains any free space. This should
+ * be tested before storing data to the buffer, to ensure that no data is lost due to a
+ * buffer overrun.
+ *
+ * \param[in,out] Buffer Pointer to a ring buffer structure to insert into
+ *
+ * \return Boolean true if the buffer contains no free space, false otherwise
+ */
+ static inline bool RingBuffer_IsFull(RingBuff_t* const Buffer)
+ {
+ bool IsFull;
+
+ ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
+ {
+ IsFull = (Buffer->Count == BUFFER_SIZE);
+ }
+
+ return IsFull;
+ }
+
/** Atomically inserts an element into the ring buffer.
*
* \param[in,out] Buffer Pointer to a ring buffer structure to insert into
diff --git a/Projects/USBtoSerial/Lib/LightweightRingBuff.h b/Projects/USBtoSerial/Lib/LightweightRingBuff.h
index 9c25707b4..0ffe792dc 100644
--- a/Projects/USBtoSerial/Lib/LightweightRingBuff.h
+++ b/Projects/USBtoSerial/Lib/LightweightRingBuff.h
@@ -75,6 +75,26 @@
Buffer->Count = 0;
}
+ /** Atomically determines if the specified ring buffer contains any free space. This should
+ * be tested before storing data to the buffer, to ensure that no data is lost due to a
+ * buffer overrun.
+ *
+ * \param[in,out] Buffer Pointer to a ring buffer structure to insert into
+ *
+ * \return Boolean true if the buffer contains no free space, false otherwise
+ */
+ static inline bool RingBuffer_IsFull(RingBuff_t* const Buffer)
+ {
+ bool IsFull;
+
+ ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
+ {
+ IsFull = (Buffer->Count == BUFFER_SIZE);
+ }
+
+ return IsFull;
+ }
+
/** Atomically inserts an element into the ring buffer.
*
* \param[in,out] Buffer Pointer to a ring buffer structure to insert into
diff --git a/Projects/USBtoSerial/USBtoSerial.c b/Projects/USBtoSerial/USBtoSerial.c
index 145047cbc..1cd6f5563 100644
--- a/Projects/USBtoSerial/USBtoSerial.c
+++ b/Projects/USBtoSerial/USBtoSerial.c
@@ -84,7 +84,7 @@ int main(void)
/* Read bytes from the USB OUT endpoint into the USART transmit buffer */
for (uint8_t DataBytesRem = CDC_Device_BytesReceived(&VirtualSerial_CDC_Interface); DataBytesRem != 0; DataBytesRem--)
{
- if (!(BUFFER_SIZE - USBtoUSART_Buffer.Count))
+ if (RingBuffer_IsFull(&USBtoUSART_Buffer))
break;
RingBuffer_AtomicInsert(&USBtoUSART_Buffer, CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface));
diff --git a/Projects/XPLAINBridge/Lib/LightweightRingBuff.h b/Projects/XPLAINBridge/Lib/LightweightRingBuff.h
index 9c25707b4..0ffe792dc 100644
--- a/Projects/XPLAINBridge/Lib/LightweightRingBuff.h
+++ b/Projects/XPLAINBridge/Lib/LightweightRingBuff.h
@@ -75,6 +75,26 @@
Buffer->Count = 0;
}
+ /** Atomically determines if the specified ring buffer contains any free space. This should
+ * be tested before storing data to the buffer, to ensure that no data is lost due to a
+ * buffer overrun.
+ *
+ * \param[in,out] Buffer Pointer to a ring buffer structure to insert into
+ *
+ * \return Boolean true if the buffer contains no free space, false otherwise
+ */
+ static inline bool RingBuffer_IsFull(RingBuff_t* const Buffer)
+ {
+ bool IsFull;
+
+ ATOMIC_BLOCK(ATOMIC_RESTORESTATE)
+ {
+ IsFull = (Buffer->Count == BUFFER_SIZE);
+ }
+
+ return IsFull;
+ }
+
/** Atomically inserts an element into the ring buffer.
*
* \param[in,out] Buffer Pointer to a ring buffer structure to insert into
diff --git a/Projects/XPLAINBridge/XPLAINBridge.c b/Projects/XPLAINBridge/XPLAINBridge.c
index f08dfc5c7..3bbc0bc65 100644
--- a/Projects/XPLAINBridge/XPLAINBridge.c
+++ b/Projects/XPLAINBridge/XPLAINBridge.c
@@ -120,7 +120,7 @@ void UARTBridge_Task(void)
return;
/* Read bytes from the USB OUT endpoint into the UART transmit buffer */
- if (CDC_Device_BytesReceived(&VirtualSerial_CDC_Interface))
+ if (CDC_Device_BytesReceived(&VirtualSerial_CDC_Interface) && !(RingBuffer_IsFull(&USBtoUART_Buffer)))
RingBuffer_AtomicInsert(&USBtoUART_Buffer, CDC_Device_ReceiveByte(&VirtualSerial_CDC_Interface));
/* Check if the software UART flush timer has expired */
--
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