From 5e1f8c9e20a92743eefc9a82c2db835213905e26 Mon Sep 17 00:00:00 2001 From: Theodore Ts'o Date: Tue, 28 Oct 2008 13:21:55 -0400 Subject: 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" Cc: akpm@linux-foundation.org Cc: linux-kernel@vger.kernel.org --- fs/ext3/hash.c | 77 +++++++++++++++++++++++++++++++++++++++++++++++++-------- fs/ext3/namei.c | 7 ++++++ fs/ext3/super.c | 12 +++++++++ 3 files changed, 86 insertions(+), 10 deletions(-) (limited to 'fs/ext3') diff --git a/fs/ext3/hash.c b/fs/ext3/hash.c index c30e149fbd2..7d215b4d4f2 100644 --- a/fs/ext3/hash.c +++ b/fs/ext3/hash.c @@ -35,23 +35,71 @@ static void TEA_transform(__u32 buf[4], __u32 const in[]) /* 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; + __u32 hash, hash0 = 0x12a3fe2d, hash1 = 0x37abe8f9; + const unsigned char *ucp = (const unsigned char *) name; + + while (len--) { + hash = hash1 + (hash0 ^ (((int) *ucp++) * 7152373)); + + if (hash & 0x80000000) + hash -= 0x7fffffff; + hash1 = hash0; + hash0 = hash; + } + return hash0 << 1; +} + +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--) { - __u32 hash = hash1 + (hash0 ^ (*name++ * 7152373)); + hash = hash1 + (hash0 ^ (((int) *scp++) * 7152373)); - if (hash & 0x80000000) hash -= 0x7fffffff; + 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 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 @@ static void str2hashbuf(const char *msg, int len, __u32 *buf, int num) 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 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo) 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 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo) } switch (hinfo->hash_version) { + case DX_HASH_LEGACY_UNSIGNED: + hash = dx_hack_hash_unsigned(name, len); + break; case DX_HASH_LEGACY: - hash = dx_hack_hash(name, len); + 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 @@ int ext3fs_dirhash(const char *name, int len, struct dx_hash_info *hinfo) 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; diff --git a/fs/ext3/namei.c b/fs/ext3/namei.c index 1dd2abe6313..287b304d42a 100644 --- a/fs/ext3/namei.c +++ b/fs/ext3/namei.c @@ -368,6 +368,8 @@ dx_probe(struct qstr *entry, struct inode *dir, goto fail; } hinfo->hash_version = root->info.hash_version; + if (hinfo->hash_version <= DX_HASH_TEA) + hinfo->hash_version += EXT3_SB(dir->i_sb)->s_hash_unsigned; hinfo->seed = EXT3_SB(dir->i_sb)->s_hash_seed; if (entry) ext3fs_dirhash(entry->name, entry->len, hinfo); @@ -636,6 +638,9 @@ int ext3_htree_fill_tree(struct file *dir_file, __u32 start_hash, dir = dir_file->f_path.dentry->d_inode; if (!(EXT3_I(dir)->i_flags & EXT3_INDEX_FL)) { hinfo.hash_version = EXT3_SB(dir->i_sb)->s_def_hash_version; + if (hinfo.hash_version <= DX_HASH_TEA) + hinfo.hash_version += + EXT3_SB(dir->i_sb)->s_hash_unsigned; hinfo.seed = EXT3_SB(dir->i_sb)->s_hash_seed; count = htree_dirblock_to_tree(dir_file, dir, 0, &hinfo, start_hash, start_minor_hash); @@ -1398,6 +1403,8 @@ static int make_indexed_dir(handle_t *handle, struct dentry *dentry, /* Initialize as for dx_probe */ hinfo.hash_version = root->info.hash_version; + if (hinfo.hash_version <= DX_HASH_TEA) + hinfo.hash_version += EXT3_SB(dir->i_sb)->s_hash_unsigned; hinfo.seed = EXT3_SB(dir->i_sb)->s_hash_seed; ext3fs_dirhash(name, namelen, &hinfo); frame = frames; diff --git a/fs/ext3/super.c b/fs/ext3/super.c index f6c94f232ec..541d5e4f7f6 100644 --- a/fs/ext3/super.c +++ b/fs/ext3/super.c @@ -1744,6 +1744,18 @@ static int ext3_fill_super (struct super_block *sb, void *data, int silent) for (i=0; i < 4; i++) sbi->s_hash_seed[i] = le32_to_cpu(es->s_hash_seed[i]); sbi->s_def_hash_version = es->s_def_hash_version; + i = le32_to_cpu(es->s_flags); + if (i & EXT2_FLAGS_UNSIGNED_HASH) + sbi->s_hash_unsigned = 3; + else if ((i & EXT2_FLAGS_SIGNED_HASH) == 0) { +#ifdef __CHAR_UNSIGNED__ + es->s_flags |= cpu_to_le32(EXT2_FLAGS_UNSIGNED_HASH); + sbi->s_hash_unsigned = 3; +#else + es->s_flags |= cpu_to_le32(EXT2_FLAGS_SIGNED_HASH); +#endif + sb->s_dirt = 1; + } if (sbi->s_blocks_per_group > blocksize * 8) { printk (KERN_ERR -- cgit v1.2.3