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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 <linux/kernel.h>
9 #include <linux/types.h>
10 
LZ4_readLE16(const void * src)11 static u16 LZ4_readLE16(const void *src) { return le16_to_cpu(*(u16 *)src); }
LZ4_copy4(void * dst,const void * src)12 static void LZ4_copy4(void *dst, const void *src) { *(u32 *)dst = *(u32 *)src; }
LZ4_copy8(void * dst,const void * src)13 static void LZ4_copy8(void *dst, const void *src) { *(u64 *)dst = *(u64 *)src; }
14 
15 typedef  uint8_t BYTE;
16 typedef uint16_t U16;
17 typedef uint32_t U32;
18 typedef  int32_t S32;
19 typedef uint64_t U64;
20 
21 #define FORCE_INLINE static inline __attribute__((always_inline))
22 
23 /* Unaltered (except removing unrelated code) from github.com/Cyan4973/lz4. */
24 #include "lz4.c"	/* #include for inlining, do not link! */
25 
26 #define LZ4F_MAGIC 0x184D2204
27 
28 struct lz4_frame_header {
29 	u32 magic;
30 	union {
31 		u8 flags;
32 		struct {
33 			u8 reserved0:2;
34 			u8 has_content_checksum:1;
35 			u8 has_content_size:1;
36 			u8 has_block_checksum:1;
37 			u8 independent_blocks:1;
38 			u8 version:2;
39 		};
40 	};
41 	union {
42 		u8 block_descriptor;
43 		struct {
44 			u8 reserved1:4;
45 			u8 max_block_size:3;
46 			u8 reserved2:1;
47 		};
48 	};
49 	/* + u64 content_size iff has_content_size is set */
50 	/* + u8 header_checksum */
51 } __packed;
52 
53 struct lz4_block_header {
54 	union {
55 		u32 raw;
56 		struct {
57 			u32 size:31;
58 			u32 not_compressed:1;
59 		};
60 	};
61 	/* + size bytes of data */
62 	/* + u32 block_checksum iff has_block_checksum is set */
63 } __packed;
64 
ulz4fn(const void * src,size_t srcn,void * dst,size_t * dstn)65 int ulz4fn(const void *src, size_t srcn, void *dst, size_t *dstn)
66 {
67 	const void *end = dst + *dstn;
68 	const void *in = src;
69 	void *out = dst;
70 	int has_block_checksum;
71 	int ret;
72 	*dstn = 0;
73 
74 	{ /* With in-place decompression the header may become invalid later. */
75 		const struct lz4_frame_header *h = in;
76 
77 		if (srcn < sizeof(*h) + sizeof(u64) + sizeof(u8))
78 			return -EINVAL;	/* input overrun */
79 
80 		/* We assume there's always only a single, standard frame. */
81 		if (le32_to_cpu(h->magic) != LZ4F_MAGIC || h->version != 1)
82 			return -EPROTONOSUPPORT;	/* unknown format */
83 		if (h->reserved0 || h->reserved1 || h->reserved2)
84 			return -EINVAL;	/* reserved must be zero */
85 		if (!h->independent_blocks)
86 			return -EPROTONOSUPPORT; /* we can't support this yet */
87 		has_block_checksum = h->has_block_checksum;
88 
89 		in += sizeof(*h);
90 		if (h->has_content_size)
91 			in += sizeof(u64);
92 		in += sizeof(u8);
93 	}
94 
95 	while (1) {
96 		struct lz4_block_header b;
97 
98 		b.raw = le32_to_cpu(*(u32 *)in);
99 		in += sizeof(struct lz4_block_header);
100 
101 		if (in - src + b.size > srcn) {
102 			ret = -EINVAL;		/* input overrun */
103 			break;
104 		}
105 
106 		if (!b.size) {
107 			ret = 0;	/* decompression successful */
108 			break;
109 		}
110 
111 		if (b.not_compressed) {
112 			size_t size = min((ptrdiff_t)b.size, end - out);
113 			memcpy(out, in, size);
114 			out += size;
115 			if (size < b.size) {
116 				ret = -ENOBUFS;	/* output overrun */
117 				break;
118 			}
119 		} else {
120 			/* constant folding essential, do not touch params! */
121 			ret = LZ4_decompress_generic(in, out, b.size,
122 					end - out, endOnInputSize,
123 					full, 0, noDict, out, NULL, 0);
124 			if (ret < 0) {
125 				ret = -EPROTO;	/* decompression error */
126 				break;
127 			}
128 			out += ret;
129 		}
130 
131 		in += b.size;
132 		if (has_block_checksum)
133 			in += sizeof(u32);
134 	}
135 
136 	*dstn = out - dst;
137 	return ret;
138 }
139