From: Rich Felker <dalias@aerifal.cx>
Date: Sat, 15 Sep 2012 07:03:21 +0000 (-0400)
Subject: revert low rounds-count limits in crypt hashes
X-Git-Url: http://nsz.repo.hu/git/?p=musl;a=commitdiff_plain;h=aeaceb1fa89b865eb0bca739da9c450b5a054866

revert low rounds-count limits in crypt hashes

it was determined in discussion that these kind of limits are not
sufficient to protect single-threaded servers against denial of
service attacks from maliciously large round counts. the time scales
simply vary too much; many users will want login passwords with rounds
counts on a scale that gives decisecond latency, while highly loaded
webservers will need millisecond latency or shorter.

still some limit is left in place; the idea is not to protect against
attacks, but to avoid the runtime of a single call to crypt being, for
all practical purposes, infinite, so that configuration errors can be
caught and fixed without bringing down whole systems. these limits are
very high, on the order of minute-long runtimes for modest systems.
---

diff --git a/src/crypt/crypt_blowfish.c b/src/crypt/crypt_blowfish.c
index bd37be84..d3f79851 100644
--- a/src/crypt/crypt_blowfish.c
+++ b/src/crypt/crypt_blowfish.c
@@ -625,7 +625,7 @@ static char *BF_crypt(const char *key, const char *setting,
 	}
 
 	count = (BF_word)1 << ((setting[4] - '0') * 10 + (setting[5] - '0'));
-	if (count < min || count > 2048 || BF_decode(data.binary.salt, &setting[7], 16)) {
+	if (count < min || BF_decode(data.binary.salt, &setting[7], 16)) {
 		return NULL;
 	}
 	BF_swap(data.binary.salt, 4);
diff --git a/src/crypt/crypt_des.c b/src/crypt/crypt_des.c
index d7b2b15a..4454a130 100644
--- a/src/crypt/crypt_des.c
+++ b/src/crypt/crypt_des.c
@@ -911,7 +911,7 @@ static char *_crypt_extended_r_uut(const char *_key, const char *_setting, char
 				return NULL;
 			count |= value << (i - 1) * 6;
 		}
-		if (!count || count > 262143)
+		if (!count)
 			return NULL;
 
 		for (i = 5, salt = 0; i < 9; i++) {
diff --git a/src/crypt/crypt_sha256.c b/src/crypt/crypt_sha256.c
index 2dc27ee7..076e4b16 100644
--- a/src/crypt/crypt_sha256.c
+++ b/src/crypt/crypt_sha256.c
@@ -172,7 +172,7 @@ static char *to64(char *s, unsigned int u, int n)
 #define SALT_MAX 16
 #define ROUNDS_DEFAULT 5000
 #define ROUNDS_MIN 1000
-#define ROUNDS_MAX 50000
+#define ROUNDS_MAX 9999999
 
 /* hash n bytes of the repeated md message digest */
 static void hashmd(struct sha256 *s, unsigned int n, const void *md)
diff --git a/src/crypt/crypt_sha512.c b/src/crypt/crypt_sha512.c
index 2c0de698..0f1de814 100644
--- a/src/crypt/crypt_sha512.c
+++ b/src/crypt/crypt_sha512.c
@@ -193,7 +193,7 @@ static char *to64(char *s, unsigned int u, int n)
 #define SALT_MAX 16
 #define ROUNDS_DEFAULT 5000
 #define ROUNDS_MIN 1000
-#define ROUNDS_MAX 20000
+#define ROUNDS_MAX 9999999
 
 /* hash n bytes of the repeated md message digest */
 static void hashmd(struct sha512 *s, unsigned int n, const void *md)