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authorRich Felker <dalias@aerifal.cx>2011-02-18 17:04:56 -0500
committerRich Felker <dalias@aerifal.cx>2011-02-18 17:04:56 -0500
commit446b4207cc7a30d8a4d5b2445a5a1b27d440f55d (patch)
tree3bc2e2969267d28e3c5b841c25e025afbb1623d4 /src/temp/mkdtemp.c
parent3e9e30166f22f8fb0d5664500bb52a00d1a3c6a3 (diff)
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major improvements to temp file name generator
use current time in nanoseconds and some potentially-random (if aslr
is enabled) pointer values for the initial tempfile name generation,
and step via a cheap linear prng on collisions. limit the number of
retry attempts to prevent denial of service attacks even if an
attacker can guess the filenames.
Diffstat (limited to 'src/temp/mkdtemp.c')
-rw-r--r--src/temp/mkdtemp.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/src/temp/mkdtemp.c b/src/temp/mkdtemp.c
index 162d98b0..f2ecc510 100644
--- a/src/temp/mkdtemp.c
+++ b/src/temp/mkdtemp.c
@@ -12,7 +12,8 @@ char *__mktemp(char *);
 
 char *mkdtemp(char *template)
 {
-	for (;;) {
+	int retries = 100;
+	while (retries--) {
 		if (!__mktemp(template)) return 0;
 		if (!mkdir(template, 0700)) return template;
 		if (errno != EEXIST) return 0;
@@ -20,4 +21,5 @@ char *mkdtemp(char *template)
 		 * that we have a valid template string */
 		strcpy(template+strlen(template)-6, "XXXXXX");
 	}
+	return 0;
 }