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Recommendations

FIO00-C. Take care when creating format strings

FIO01-C. Be careful using functions that use file names for identification

FIO02-C. Canonicalize path names originating from untrusted sources

FIO03-C. Do not make assumptions about fopen() and file creation

FIO04-C. Detect and handle input and output errors

FIO05-C. Identify files using multiple file attributes

FIO06-C. Create files with appropriate access permissions

FIO07-C. Prefer fseek() to rewind()

FIO08-C. Take care when calling remove() on an open file

FIO09-C. Be careful with binary data when transferring data across systems

FIO10-C. Take care when using the rename() function

FIO11-C. Take care when specifying the mode parameter of fopen()

FIO12-C. Prefer setvbuf() to setbuf()

FIO13-C. Never push back anything other than one read character

FIO14-C. Understand the difference between text mode and binary mode with file streams

FIO15-C. Ensure that file operations are performed in a secure directory

FIO16-C. Limit access to files by creating a jail

FIO17-C. Do not rely on an ending null character when using fread()

Rules

FIO30-C. Exclude user input from format strings

FIO31-C. Do not simultaneously open the same file multiple times

FIO32-C. Do not perform operations on devices that are only appropriate for files

FIO33-C. Detect and handle input output errors resulting in undefined behavior

FIO34-C. Use int to capture the return value of character IO functions

FIO35-C. Use feof() and ferror() to detect end-of-file and file errors when sizeof(int) == sizeof(char)

FIO36-C. Do not assume a new-line character is read when using fgets()

FIO37-C. Do not assume character data has been read

FIO38-C. Do not use a copy of a FILE object for input and output

FIO39-C. Do not alternately input and output from a stream without an intervening flush or positioning call

FIO40-C. Reset strings on fgets() failure

FIO41-C. Do not call getc() or putc() with stream arguments that have side effects

FIO42-C. Ensure files are properly closed when they are no longer needed

FIO43-C. Do not create temporary files in shared directories

FIO44-C. Only use values for fsetpos() that are returned from fgetpos()

Risk Assessment Summary

Recommendation	Severity	Likelihood	Remediation Cost	Priority	Level
FIO00-C	high	unlikely	medium	P6	L2
FIO01-C	medium	likely	medium	P12	L1
FIO02-C	medium	probable	medium	P8	L2
FIO03-C	medium	probable	high	P4	L3
FIO04-C	medium	probable	high	P4	L3
FIO05-C	medium	probable	medium	P8	L2
FIO06-C	medium	probable	high	P4	L3
FIO07-C	low	unlikely	low	P3	L3
FIO08-C	medium	probable	high	P4	L3
FIO09-C	medium	probable	high	P4	L3
FIO10-C	medium	probable	medium	P8	L2
FIO11-C	medium	probable	medium	P8	L2
FIO12-C	low	unlikely	medium	P2	L3
FIO13-C	medium	probable	high	P4	L3
FIO14-C	low	probable	high	P2	L3
FIO15-C	high	probable	high	P6	L2
FIO16-C	medium	probable	high	P4	L3
FIO17-C	low	likely	medium	P6	L2

Rule	Severity	Likelihood	Remediation Cost	Priority	Level
FIO30-C	high	likely	medium	P18	L1
FIO31-C	medium	probable	high	P4	L3
FIO32-C	medium	unlikely	medium	P4	L3
FIO33-C	high	probable	medium	P12	L1
FIO34-C	high	probable	medium	P12	L1
FIO35-C	low	unlikely	medium	P2	L3
FIO36-C	medium	likely	medium	P12	L1
FIO37-C	high	probable	medium	P12	L1
FIO38-C	low	probable	medium	P4	L3
FIO39-C	low	likely	medium	P6	L2
FIO40-C	low	probable	medium	P4	L3
FIO41-C	low	unlikely	medium	P2	L3
FIO42-C	medium	unlikely	medium	P4	L3
FIO43-C	high	probable	medium	P12	L1
FIO44-C	medium	unlikely	medium	P4	L3

Related Rules and Recommendations

CERT C Secure Coding Standard FIO00-C. Take care when creating format strings