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[libpng16] Unlink temporary file immediately in pngstest (PNG_USE_MKSTEMP)

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This commit is contained in:
Glenn Randers-Pehrson 2015-06-11 16:28:54 -05:00
parent 81487c8b54
commit c6f629ffdd
1 changed files with 22 additions and 4 deletions
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26
contrib/libtests/pngstest.c
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@ -3250,16 +3250,34 @@ write_one_file(Image *output, Image *image, int convert_to_8bit)
#else
/* Experimental. Coverity says tmpfile() is insecure because it
* generates predictable names.
*
* It is possible to satisfy Coverity by using mkstemp(); however,
* any platform supporting mkstemp() undoubtedly has a secure tmpfile()
* implementation as well, and doesn't need the fix. Note that
* the fix won't work on platforms that don't support mkstemp().
*
* https://www.securecoding.cert.org/confluence/display/c/
* FIO21-C.+Do+not+create+temporary+files+in+shared+directories
* says that most historic implementations of tmpfile() provide
* only a limited number of possible temporary file names
* (usually 26) before file names are recycled. That article also
* provides a secure solution that unfortunately depends upon mkstemp().
*/
char tmpfile[] = "pngstest-XXXXXX";
int filedes;
FILE *f;
umask(0600);
umask(0177);
filedes = mkstemp(tmpfile);
if (filedes >= 0)
f = fdopen(filedes,"w+");
else
if (filedes < 0)
f = NULL;
else
{
f = fdopen(filedes,"w+");
/* Hide the filename immediately and ensure that the file does
* not exist after the program ends
*/
(void) unlink(tmpfile);
}
#endif
if (f != NULL)