Fix buffer-overflow assigning global Wire instances. #317
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Two pointer arrays declared, which contain pointers to the global SCI/I2C Wire instances: "g_SCIWires" and "g_I2CWires". Since there's a different number of SCI vs pure I2C "I2C" interfaces those buffers are of different size. Due to a typo the constant declaring the size of the pointe rarray for "g_SCIWires" ("TWOWIRE_MAX_SCI_CHANNELS") was used to define the size of "g_I2CWires" and vice versa. This had the result that on Portenta C33, íf you were calling "TwoWire::_begin()" for "Wire3" (which has channel "3") a buffer overflow occurs and random memory is overwritten.
aentinger
added
type: imperfection
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Brilliant @aentinger ! Thanks a lot for your help with this 🙏 |
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Two pointer arrays declared, which contain pointers to the global SCI/I2C Wire instances: "g_SCIWires" and "g_I2CWires". Since there's a different number of SCI vs pure I2C "I2C" interfaces those buffers are of different size. Due to a typo the constant declaring the size of the pointe rarray for "g_SCIWires" ("TWOWIRE_MAX_SCI_CHANNELS") was used to define the size of "g_I2CWires" and vice versa. This had the result that on Portenta C33, íf you were calling "TwoWire::_begin()" for "Wire3" (which has channel "3") a buffer overflow occurs and random memory is overwritten.