lib/lz4_wrapper.c

   1 // SPDX-License-Identifier: GPL 2.0+ OR BSD-3-Clause
   2 /*
   3  * Copyright 2015 Google Inc.
   4  */
   5
   6 #include <common.h>
   7 #include <compiler.h>
   8 #include <image.h>
   9 #include <lz4.h>
  10 #include <linux/kernel.h>
  11 #include <linux/types.h>
  12 #include <asm/unaligned.h>
  13
  14 static u16 LZ4_readLE16(const void *src) { return le16_to_cpu(*(u16 *)src); }
  15 static void LZ4_copy4(void *dst, const void *src) { *(u32 *)dst = *(u32 *)src; }
  16 static void LZ4_copy8(void *dst, const void *src) { *(u64 *)dst = *(u64 *)src; }
  17
  18 typedef  uint8_t BYTE;
  19 typedef uint16_t U16;
  20 typedef uint32_t U32;
  21 typedef  int32_t S32;
  22 typedef uint64_t U64;
  23
  24 #define FORCE_INLINE static inline __attribute__((always_inline))
  25
  26 /* lz4.c is unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
  27 #include "lz4.c"        /* #include for inlining, do not link! */
  28
  29 #define LZ4F_BLOCKUNCOMPRESSED_FLAG 0x80000000U
  30
  31 int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
  32 {
  33         const void *end = dst + *dstn;
  34         const void *in = src;
  35         void *out = dst;
  36         int has_block_checksum;
  37         int ret;
  38         *dstn = 0;
  39
  40         { /* With in-place decompression the header may become invalid later. */
  41                 u32 magic;
  42                 u8 flags, version, independent_blocks, has_content_size;
  43                 u8 block_desc;
  44
  45                 if (srcn < sizeof(u32) + 3*sizeof(u8))
  46                         return -EINVAL; /* input overrun */
  47
  48                 magic = get_unaligned_le32(in);
  49                 in += sizeof(u32);
  50                 flags = *(u8 *)in;
  51                 in += sizeof(u8);
  52                 block_desc = *(u8 *)in;
  53                 in += sizeof(u8);
  54
  55                 version = (flags >> 6) & 0x3;
  56                 independent_blocks = (flags >> 5) & 0x1;
  57                 has_block_checksum = (flags >> 4) & 0x1;
  58                 has_content_size = (flags >> 3) & 0x1;
  59
  60                 /* We assume there's always only a single, standard frame. */
  61                 if (magic != LZ4F_MAGIC || version != 1)
  62                         return -EPROTONOSUPPORT;        /* unknown format */
  63                 if ((flags & 0x03) || (block_desc & 0x8f))
  64                         return -EINVAL; /* reserved bits must be zero */
  65                 if (!independent_blocks)
  66                         return -EPROTONOSUPPORT; /* we can't support this yet */
  67
  68                 if (has_content_size) {
  69                         if (srcn < sizeof(u32) + 3*sizeof(u8) + sizeof(u64))
  70                                 return -EINVAL; /* input overrun */
  71                         in += sizeof(u64);
  72                 }
  73                 /* Header checksum byte */
  74                 in += sizeof(u8);
  75         }
  76
  77         while (1) {
  78                 u32 block_header, block_size;
  79
  80                 block_header = get_unaligned_le32(in);
  81                 in += sizeof(u32);
  82                 block_size = block_header & ~LZ4F_BLOCKUNCOMPRESSED_FLAG;
  83
  84                 if (in - src + block_size > srcn) {
  85                         ret = -EINVAL;          /* input overrun */
  86                         break;
  87                 }
  88
  89                 if (!block_size) {
  90                         ret = 0;        /* decompression successful */
  91                         break;
  92                 }
  93
  94                 if (block_header & LZ4F_BLOCKUNCOMPRESSED_FLAG) {
  95                         size_t size = min((ptrdiff_t)block_size, end - out);
  96                         memcpy(out, in, size);
  97                         out += size;
  98                         if (size < block_size) {
  99                                 ret = -ENOBUFS; /* output overrun */
 100                                 break;
 101                         }
 102                 } else {
 103                         /* constant folding essential, do not touch params! */
 104                         ret = LZ4_decompress_generic(in, out, block_size,
 105                                         end - out, endOnInputSize,
 106                                         full, 0, noDict, out, NULL, 0);
 107                         if (ret < 0) {
 108                                 ret = -EPROTO;  /* decompression error */
 109                                 break;
 110                         }
 111                         out += ret;
 112                 }
 113
 114                 in += block_size;
 115                 if (has_block_checksum)
 116                         in += sizeof(u32);
 117         }
 118
 119         *dstn = out - dst;
 120         return ret;
 121 }