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Prevent buffer overflow in AppendGraph()

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This commit is contained in:
Henry Gabryjelski 2023-02-18 12:50:05 -08:00
commit 28af1a870d
1 changed files with 23 additions and 5 deletions
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28
client/src/graph.c
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@ -29,21 +29,39 @@ int g_GraphBuffer[MAX_GRAPH_TRACE_LEN];
size_t g_GraphTraceLen;
/* write a manchester bit to the graph
TODO, verfy that this doesn't overflow buffer (iceman)
*/
void AppendGraph(bool redraw, uint16_t clock, int bit) {
uint8_t half = clock / 2;
uint16_t half = clock / 2;
uint16_t end = clock;
uint16_t i;
// overflow/underflow safe checks ... Assumptions:
// _Assert(g_GraphTraceLen >= 0);
// _Assert(g_GraphTraceLen <= MAX_GRAPH_TRACE_LEN);
// If this occurs, allow partial rendering, up to the last sample...
if ((MAX_GRAPH_TRACE_LEN - g_GraphTraceLen) < half) {
PrintAndLogEx(DEBUG, "WARNING: AppendGraph() - Request exceeds max graph length");
end = MAX_GRAPH_TRACE_LEN - g_GraphTraceLen;
half = end;
}
if ((MAX_GRAPH_TRACE_LEN - g_GraphTraceLen) < end) {
PrintAndLogEx(DEBUG, "WARNING: AppendGraph() - Request exceeds max graph length");
end = MAX_GRAPH_TRACE_LEN - g_GraphTraceLen;
}
//set first half the clock bit (all 1's or 0's for a 0 or 1 bit)
for (i = 0; i < half; ++i)
for (i = 0; i < half; ++i) {
g_GraphBuffer[g_GraphTraceLen++] = bit;
}
//set second half of the clock bit (all 0's or 1's for a 0 or 1 bit)
for (; i < clock; ++i)
for (; i < end; ++i) {
g_GraphBuffer[g_GraphTraceLen++] = bit ^ 1;
}
if (redraw)
if (redraw) {
RepaintGraphWindow();
}
}
// clear out our graph window