1 /* 2 * Copyright 2015 Google Inc. 3 * 4 * SPDX-License-Identifier: GPL 2.0+ BSD-3-Clause 5 */ 6 7 #include <common.h> 8 #include <compiler.h> 9 #include <linux/kernel.h> 10 #include <linux/types.h> 11 #include <asm/unaligned.h> 12 13 static u16 LZ4_readLE16(const void *src) 14 { 15 return get_unaligned_le16(src); 16 } 17 static void LZ4_copy4(void *dst, const void *src) 18 { 19 put_unaligned(get_unaligned((const u32 *)src), (u32 *)dst); 20 } 21 static void LZ4_copy8(void *dst, const void *src) 22 { 23 put_unaligned(get_unaligned((const u64 *)src), (u64 *)dst); 24 } 25 26 typedef uint8_t BYTE; 27 typedef uint16_t U16; 28 typedef uint32_t U32; 29 typedef int32_t S32; 30 typedef uint64_t U64; 31 32 #define FORCE_INLINE static inline __attribute__((always_inline)) 33 34 /* Unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */ 35 #include "lz4.c" /* #include for inlining, do not link! */ 36 37 #define LZ4F_MAGIC 0x184D2204 38 39 struct lz4_frame_header { 40 u32 magic; 41 union { 42 u8 flags; 43 struct { 44 u8 reserved0:2; 45 u8 has_content_checksum:1; 46 u8 has_content_size:1; 47 u8 has_block_checksum:1; 48 u8 independent_blocks:1; 49 u8 version:2; 50 }; 51 }; 52 union { 53 u8 block_descriptor; 54 struct { 55 u8 reserved1:4; 56 u8 max_block_size:3; 57 u8 reserved2:1; 58 }; 59 }; 60 /* + u64 content_size iff has_content_size is set */ 61 /* + u8 header_checksum */ 62 } __packed; 63 64 struct lz4_block_header { 65 union { 66 u32 raw; 67 struct { 68 u32 size:31; 69 u32 not_compressed:1; 70 }; 71 }; 72 /* + size bytes of data */ 73 /* + u32 block_checksum iff has_block_checksum is set */ 74 } __packed; 75 76 bool lz4_is_valid_header(const unsigned char *h) 77 { 78 const struct lz4_frame_header *hdr = (const struct lz4_frame_header *)h; 79 /* We assume there's always only a single, standard frame. */ 80 if (le32_to_cpu(hdr->magic) != LZ4F_MAGIC || hdr->version != 1) 81 return false; /* unknown format */ 82 if (hdr->reserved0 || hdr->reserved1 || hdr->reserved2) 83 return false; /* reserved must be zero */ 84 if (!hdr->independent_blocks) 85 return false; /* we can't support this yet */ 86 87 return true; 88 } 89 90 int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn) 91 { 92 const void *end = dst + *dstn; 93 const void *in = src; 94 void *out = dst; 95 int has_block_checksum; 96 int ret; 97 *dstn = 0; 98 99 { /* With in-place decompression the header may become invalid later. */ 100 const struct lz4_frame_header *h = in; 101 102 if (srcn < sizeof(*h) + sizeof(u64) + sizeof(u8)) 103 return -EINVAL; /* input overrun */ 104 105 /* We assume there's always only a single, standard frame. */ 106 if (le32_to_cpu(h->magic) != LZ4F_MAGIC || h->version != 1) 107 return -EPROTONOSUPPORT; /* unknown format */ 108 if (h->reserved0 || h->reserved1 || h->reserved2) 109 return -EINVAL; /* reserved must be zero */ 110 if (!h->independent_blocks) 111 return -EPROTONOSUPPORT; /* we can't support this yet */ 112 has_block_checksum = h->has_block_checksum; 113 114 in += sizeof(*h); 115 if (h->has_content_size) 116 in += sizeof(u64); 117 in += sizeof(u8); 118 } 119 120 while (1) { 121 struct lz4_block_header b; 122 123 b.raw = le32_to_cpu(*(u32 *)in); 124 in += sizeof(struct lz4_block_header); 125 126 if (in - src + b.size > srcn) { 127 ret = -EINVAL; /* input overrun */ 128 break; 129 } 130 131 if (!b.size) { 132 ret = 0; /* decompression successful */ 133 break; 134 } 135 136 if (b.not_compressed) { 137 size_t size = min((ptrdiff_t)b.size, end - out); 138 memcpy(out, in, size); 139 out += size; 140 if (size < b.size) { 141 ret = -ENOBUFS; /* output overrun */ 142 break; 143 } 144 } else { 145 /* constant folding essential, do not touch params! */ 146 ret = LZ4_decompress_generic(in, out, b.size, 147 end - out, endOnInputSize, 148 full, 0, noDict, out, NULL, 0); 149 if (ret < 0) { 150 ret = -EPROTO; /* decompression error */ 151 break; 152 } 153 out += ret; 154 } 155 156 in += b.size; 157 if (has_block_checksum) 158 in += sizeof(u32); 159 } 160 161 *dstn = out - dst; 162 return ret; 163 } 164