Fix improper null-byte termination handling #2875
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Fix a few cases where null-byte termination of strings was done unnecessarily or incorrectly. - The snprintf() function always produces a null-byte terminated string for non-negative return values, so it is not necessary to write out a null-byte as a separate step. - Also, it is unsafe to use the return value of snprintf() as an offset for placing a null-byte, because if the output was truncated the return value is the number of bytes that _would_ have been written had enough space been available. Therefore the return value may index beyond the array boundaries. - Finally, snprintf() accounts for the null-byte when limiting its output size, so there is no need to pass it a size parameter that is one less than the buffer size. Signed-off-by: Ned Bass <bass6@llnl.gov>
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Merged as: 7b2d78a Fix improper null-byte termination handling |
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Nov 29, 2014
Fix a few cases where null-byte termination of strings was done unnecessarily or incorrectly. - The snprintf() function always produces a null-byte terminated string for non-negative return values, so it is not necessary to write out a null-byte as a separate step. - Also, it is unsafe to use the return value of snprintf() as an offset for placing a null-byte, because if the output was truncated the return value is the number of bytes that _would_ have been written had enough space been available. Therefore the return value may index beyond the array boundaries. - Finally, snprintf() accounts for the null-byte when limiting its output size, so there is no need to pass it a size parameter that is one less than the buffer size. Signed-off-by: Ned Bass <bass6@llnl.gov> Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov> Closes openzfs#2875
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Fix a few cases where null-byte termination of strings was done
unnecessarily or incorrectly.
for non-negative return values, so it is not necessary to write out a
null-byte as a separate step.
for placing a null-byte, because if the output was truncated the return
value is the number of bytes that would have been written had enough
space been available. Therefore the return value may index beyond the
array boundaries.
size, so there is no need to pass it a size parameter that is one less
than the buffer size.
Signed-off-by: Ned Bass bass6@llnl.gov