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137 lines
3.0 KiB
137 lines
3.0 KiB
// SPDX-License-Identifier: GPL-2.0 |
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/* |
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* fs/f2fs/hash.c |
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* |
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* Copyright (c) 2012 Samsung Electronics Co., Ltd. |
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* http://www.samsung.com/ |
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* |
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* Portions of this code from linux/fs/ext3/hash.c |
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* |
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* Copyright (C) 2002 by Theodore Ts'o |
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*/ |
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#include <linux/types.h> |
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#include <linux/fs.h> |
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#include <linux/f2fs_fs.h> |
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#include <linux/pagemap.h> |
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#include <linux/unicode.h> |
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#include "f2fs.h" |
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/* |
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* Hashing code copied from ext3 |
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*/ |
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#define DELTA 0x9E3779B9 |
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static void TEA_transform(unsigned int buf[4], unsigned int const in[]) |
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{ |
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__u32 sum = 0; |
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__u32 b0 = buf[0], b1 = buf[1]; |
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__u32 a = in[0], b = in[1], c = in[2], d = in[3]; |
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int n = 16; |
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do { |
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sum += DELTA; |
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b0 += ((b1 << 4)+a) ^ (b1+sum) ^ ((b1 >> 5)+b); |
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b1 += ((b0 << 4)+c) ^ (b0+sum) ^ ((b0 >> 5)+d); |
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} while (--n); |
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buf[0] += b0; |
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buf[1] += b1; |
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} |
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static void str2hashbuf(const unsigned char *msg, size_t len, |
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unsigned int *buf, int num) |
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{ |
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unsigned pad, val; |
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int i; |
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pad = (__u32)len | ((__u32)len << 8); |
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pad |= pad << 16; |
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val = pad; |
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if (len > num * 4) |
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len = num * 4; |
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for (i = 0; i < len; i++) { |
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if ((i % 4) == 0) |
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val = pad; |
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val = msg[i] + (val << 8); |
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if ((i % 4) == 3) { |
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*buf++ = val; |
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val = pad; |
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num--; |
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} |
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} |
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if (--num >= 0) |
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*buf++ = val; |
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while (--num >= 0) |
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*buf++ = pad; |
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} |
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static u32 TEA_hash_name(const u8 *p, size_t len) |
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{ |
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__u32 in[8], buf[4]; |
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/* Initialize the default seed for the hash checksum functions */ |
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buf[0] = 0x67452301; |
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buf[1] = 0xefcdab89; |
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buf[2] = 0x98badcfe; |
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buf[3] = 0x10325476; |
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while (1) { |
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str2hashbuf(p, len, in, 4); |
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TEA_transform(buf, in); |
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p += 16; |
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if (len <= 16) |
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break; |
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len -= 16; |
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} |
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return buf[0] & ~F2FS_HASH_COL_BIT; |
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} |
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/* |
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* Compute @fname->hash. For all directories, @fname->disk_name must be set. |
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* For casefolded directories, @fname->usr_fname must be set, and also |
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* @fname->cf_name if the filename is valid Unicode and is not "." or "..". |
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*/ |
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void f2fs_hash_filename(const struct inode *dir, struct f2fs_filename *fname) |
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{ |
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const u8 *name = fname->disk_name.name; |
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size_t len = fname->disk_name.len; |
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WARN_ON_ONCE(!name); |
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if (is_dot_dotdot(name, len)) { |
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fname->hash = 0; |
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return; |
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} |
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#if IS_ENABLED(CONFIG_UNICODE) |
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if (IS_CASEFOLDED(dir)) { |
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/* |
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* If the casefolded name is provided, hash it instead of the |
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* on-disk name. If the casefolded name is *not* provided, that |
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* should only be because the name wasn't valid Unicode or was |
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* "." or "..", so fall back to treating the name as an opaque |
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* byte sequence. Note that to handle encrypted directories, |
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* the fallback must use usr_fname (plaintext) rather than |
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* disk_name (ciphertext). |
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*/ |
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WARN_ON_ONCE(!fname->usr_fname->name); |
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if (fname->cf_name.name) { |
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name = fname->cf_name.name; |
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len = fname->cf_name.len; |
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} else { |
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name = fname->usr_fname->name; |
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len = fname->usr_fname->len; |
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} |
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if (IS_ENCRYPTED(dir)) { |
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struct qstr tmp = QSTR_INIT(name, len); |
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fname->hash = |
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cpu_to_le32(fscrypt_fname_siphash(dir, &tmp)); |
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return; |
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} |
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} |
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#endif |
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fname->hash = cpu_to_le32(TEA_hash_name(name, len)); |
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}
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