ext3: Add support for non-native signed/unsigned htree hash algorithms
The original ext3 hash algorithms assumed that variables of type char
were signed, as God and K&R intended. Unfortunately, this assumption
is not true on some architectures. Userspace support for marking
filesystems with non-native signed/unsigned chars was added two years
ago, but the kernel-side support was never added (until now).
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Cc: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org
diff --git a/fs/ext3/hash.c b/fs/ext3/hash.c
index c30e149..7d215b4 100644
--- a/fs/ext3/hash.c
+++ b/fs/ext3/hash.c
@@ -35,23 +35,71 @@
/* The old legacy hash */
-static __u32 dx_hack_hash (const char *name, int len)
+static __u32 dx_hack_hash_unsigned(const char *name, int len)
{
- __u32 hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
- while (len--) {
- __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373));
+ __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+ const unsigned char *ucp = (const unsigned char *) name;
- if (hash & 0x80000000) hash -= 0x7fffffff;
+ while (len--) {
+ hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373));
+
+ if (hash & 0x80000000)
+ hash -= 0x7fffffff;
hash1 = hash0;
hash0 = hash;
}
- return (hash0 << 1);
+ return hash0 << 1;
}
-static void str2hashbuf(const char *msg, int len, __u32 *buf, int num)
+static __u32 dx_hack_hash_signed(const char *name, int len)
+{
+ __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9;
+ const signed char *scp = (const signed char *) name;
+
+ while (len--) {
+ hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373));
+
+ if (hash & 0x80000000)
+ hash -= 0x7fffffff;
+ hash1 = hash0;
+ hash0 = hash;
+ }
+ return hash0 << 1;
+}
+
+static void str2hashbuf_signed(const char *msg, int len, __u32 *buf, int num)
{
__u32 pad, val;
int i;
+ const signed char *scp = (const signed char *) msg;
+
+ pad = (__u32)len | ((__u32)len << 8);
+ pad |= pad << 16;
+
+ val = pad;
+ if (len > num*4)
+ len = num * 4;
+ for (i = 0; i < len; i++) {
+ if ((i % 4) == 0)
+ val = pad;
+ val = ((int) scp[i]) + (val << 8);
+ if ((i % 4) == 3) {
+ *buf++ = val;
+ val = pad;
+ num--;
+ }
+ }
+ if (--num >= 0)
+ *buf++ = val;
+ while (--num >= 0)
+ *buf++ = pad;
+}
+
+static void str2hashbuf_unsigned(const char *msg, int len, __u32 *buf, int num)
+{
+ __u32 pad, val;
+ int i;
+ const unsigned char *ucp = (const unsigned char *) msg;
pad = (__u32)len | ((__u32)len << 8);
pad |= pad << 16;
@@ -62,7 +110,7 @@
for (i=0; i < len; i++) {
if ((i % 4) == 0)
val = pad;
- val = msg[i] + (val << 8);
+ val = ((int) ucp[i]) + (val << 8);
if ((i % 4) == 3) {
*buf++ = val;
val = pad;
@@ -95,6 +143,8 @@
const char *p;
int i;
__u32 in[8], buf[4];
+ void (*str2hashbuf)(const char *, int, __u32 *, int) =
+ str2hashbuf_signed;
/* Initialize the default seed for the hash checksum functions */
buf[0] = 0x67452301;
@@ -113,13 +163,18 @@
}
switch (hinfo->hash_version) {
- case DX_HASH_LEGACY:
- hash = dx_hack_hash(name, len);
+ case DX_HASH_LEGACY_UNSIGNED:
+ hash = dx_hack_hash_unsigned(name, len);
break;
+ case DX_HASH_LEGACY:
+ hash = dx_hack_hash_signed(name, len);
+ break;
+ case DX_HASH_HALF_MD4_UNSIGNED:
+ str2hashbuf = str2hashbuf_unsigned;
case DX_HASH_HALF_MD4:
p = name;
while (len > 0) {
- str2hashbuf(p, len, in, 8);
+ (*str2hashbuf)(p, len, in, 8);
half_md4_transform(buf, in);
len -= 32;
p += 32;
@@ -127,10 +182,12 @@
minor_hash = buf[2];
hash = buf[1];
break;
+ case DX_HASH_TEA_UNSIGNED:
+ str2hashbuf = str2hashbuf_unsigned;
case DX_HASH_TEA:
p = name;
while (len > 0) {
- str2hashbuf(p, len, in, 4);
+ (*str2hashbuf)(p, len, in, 4);
TEA_transform(buf, in);
len -= 16;
p += 16;