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)
  15 {
  16         return get_unaligned_le16(src);
  17 }
  18 static void LZ4_copy4(void *dst, const void *src)
  19 {
  20         put_unaligned(get_unaligned((const u32 *)src), (u32 *)dst);
  21 }
  22 static void LZ4_copy8(void *dst, const void *src)
  23 {
  24         put_unaligned(get_unaligned((const u64 *)src), (u64 *)dst);
  25 }
  26
  27 typedef  uint8_t BYTE;
  28 typedef uint16_t U16;
  29 typedef uint32_t U32;
  30 typedef  int32_t S32;
  31 typedef uint64_t U64;
  32
  33 #define FORCE_INLINE static inline __attribute__((always_inline))
  34
  35 /* lz4.c is unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
  36 #include "lz4.c"        /* #include for inlining, do not link! */
  37
  38 #define LZ4F_BLOCKUNCOMPRESSED_FLAG 0x80000000U
  39
  40 int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
  41 {
  42         const void *end = dst + *dstn;
  43         const void *in = src;
  44         void *out = dst;
  45         int has_block_checksum;
  46         int ret;
  47         *dstn = 0;
  48
  49         { /* With in-place decompression the header may become invalid later. */
  50                 u32 magic;
  51                 u8 flags, version, independent_blocks, has_content_size;
  52                 u8 block_desc;
  53
  54                 if (srcn < sizeof(u32) + 3*sizeof(u8))
  55                         return -EINVAL; /* input overrun */
  56
  57                 magic = get_unaligned_le32(in);
  58                 in += sizeof(u32);
  59                 flags = *(u8 *)in;
  60                 in += sizeof(u8);
  61                 block_desc = *(u8 *)in;
  62                 in += sizeof(u8);
  63
  64                 version = (flags >> 6) & 0x3;
  65                 independent_blocks = (flags >> 5) & 0x1;
  66                 has_block_checksum = (flags >> 4) & 0x1;
  67                 has_content_size = (flags >> 3) & 0x1;
  68
  69                 /* We assume there's always only a single, standard frame. */
  70                 if (magic != LZ4F_MAGIC || version != 1)
  71                         return -EPROTONOSUPPORT;        /* unknown format */
  72                 if ((flags & 0x03) || (block_desc & 0x8f))
  73                         return -EINVAL; /* reserved bits must be zero */
  74                 if (!independent_blocks)
  75                         return -EPROTONOSUPPORT; /* we can't support this yet */
  76
  77                 if (has_content_size) {
  78                         if (srcn < sizeof(u32) + 3*sizeof(u8) + sizeof(u64))
  79                                 return -EINVAL; /* input overrun */
  80                         in += sizeof(u64);
  81                 }
  82                 /* Header checksum byte */
  83                 in += sizeof(u8);
  84         }
  85
  86         while (1) {
  87                 u32 block_header, block_size;
  88
  89                 block_header = get_unaligned_le32(in);
  90                 in += sizeof(u32);
  91                 block_size = block_header & ~LZ4F_BLOCKUNCOMPRESSED_FLAG;
  92
  93                 if (in - src + block_size > srcn) {
  94                         ret = -EINVAL;          /* input overrun */
  95                         break;
  96                 }
  97
  98                 if (!block_size) {
  99                         ret = 0;        /* decompression successful */
 100                         break;
 101                 }
 102
 103                 if (block_header & LZ4F_BLOCKUNCOMPRESSED_FLAG) {
 104                         size_t size = min((ptrdiff_t)block_size, end - out);
 105                         memcpy(out, in, size);
 106                         out += size;
 107                         if (size < block_size) {
 108                                 ret = -ENOBUFS; /* output overrun */
 109                                 break;
 110                         }
 111                 } else {
 112                         /* constant folding essential, do not touch params! */
 113                         ret = LZ4_decompress_generic(in, out, block_size,
 114                                         end - out, endOnInputSize,
 115                                         full, 0, noDict, out, NULL, 0);
 116                         if (ret < 0) {
 117                                 ret = -EPROTO;  /* decompression error */
 118                                 break;
 119                         }
 120                         out += ret;
 121                 }
 122
 123                 in += block_size;
 124                 if (has_block_checksum)
 125                         in += sizeof(u32);
 126         }
 127
 128         *dstn = out - dst;
 129         return ret;
 130 }