1 #include <stdio.h>
2 #include <assert.h>
3 
4 #include "zbuild.h"
5 #ifdef ZLIB_COMPAT
6 #  include "zlib.h"
7 #else
8 #  include "zlib-ng.h"
9 #endif
10 
11 #define CHECK_ERR(err, msg) { \
12     if (err != Z_OK) { \
13         fprintf(stderr, "%s error: %d\n", msg, err); \
14         exit(1); \
15     } \
16 }
17 
18 static const uint8_t *data;
19 static size_t dataLen;
20 static alloc_func zalloc = NULL;
21 static free_func zfree = NULL;
22 
23 /* ===========================================================================
24  * Test deflate() with full flush
25  */
test_flush(unsigned char * compr,z_size_t * comprLen)26 void test_flush(unsigned char *compr, z_size_t *comprLen) {
27     PREFIX3(stream) c_stream; /* compression stream */
28     int err;
29     unsigned int len = (unsigned int)dataLen;
30 
31     c_stream.zalloc = zalloc;
32     c_stream.zfree = zfree;
33     c_stream.opaque = (void *)0;
34 
35     err = PREFIX(deflateInit)(&c_stream, Z_DEFAULT_COMPRESSION);
36     CHECK_ERR(err, "deflateInit");
37 
38     c_stream.next_in = (z_const unsigned char *)data;
39     c_stream.next_out = compr;
40     c_stream.avail_in = 3;
41     c_stream.avail_out = (unsigned int)*comprLen;
42     err = PREFIX(deflate)(&c_stream, Z_FULL_FLUSH);
43     CHECK_ERR(err, "deflate flush 1");
44 
45     compr[3]++; /* force an error in first compressed block */
46     c_stream.avail_in = len - 3;
47 
48     err = PREFIX(deflate)(&c_stream, Z_FINISH);
49     if (err != Z_STREAM_END) {
50         CHECK_ERR(err, "deflate flush 2");
51     }
52     err = PREFIX(deflateEnd)(&c_stream);
53     CHECK_ERR(err, "deflateEnd");
54 
55     *comprLen = (z_size_t)c_stream.total_out;
56 }
57 
58 /* ===========================================================================
59  * Test inflateSync()
60  */
test_sync(unsigned char * compr,size_t comprLen,unsigned char * uncompr,size_t uncomprLen)61 void test_sync(unsigned char *compr, size_t comprLen, unsigned char *uncompr, size_t uncomprLen) {
62     int err;
63     PREFIX3(stream) d_stream; /* decompression stream */
64 
65     d_stream.zalloc = zalloc;
66     d_stream.zfree = zfree;
67     d_stream.opaque = (void *)0;
68 
69     d_stream.next_in = compr;
70     d_stream.avail_in = 2; /* just read the zlib header */
71 
72     err = PREFIX(inflateInit)(&d_stream);
73     CHECK_ERR(err, "inflateInit");
74 
75     d_stream.next_out = uncompr;
76     d_stream.avail_out = (unsigned int)uncomprLen;
77 
78     err = PREFIX(inflate)(&d_stream, Z_NO_FLUSH);
79     CHECK_ERR(err, "inflate");
80 
81     d_stream.avail_in = (unsigned int)comprLen - 2; /* read all compressed data */
82     err = PREFIX(inflateSync)(&d_stream); /* but skip the damaged part */
83     CHECK_ERR(err, "inflateSync");
84 
85     err = PREFIX(inflate)(&d_stream, Z_FINISH);
86     if (err != Z_STREAM_END) {
87         fprintf(stderr, "inflate should report Z_STREAM_END\n");
88         exit(1);
89     }
90     err = PREFIX(inflateEnd)(&d_stream);
91     CHECK_ERR(err, "inflateEnd");
92 }
93 
LLVMFuzzerTestOneInput(const uint8_t * d,size_t size)94 int LLVMFuzzerTestOneInput(const uint8_t *d, size_t size) {
95     z_size_t comprLen = 100 + 2 * PREFIX(compressBound)(size);
96     z_size_t uncomprLen = (z_size_t)size;
97     uint8_t *compr, *uncompr;
98 
99     /* Discard inputs larger than 1Mb. */
100     static size_t kMaxSize = 1024 * 1024;
101 
102     // This test requires at least 3 bytes of input data.
103     if (size <= 3 || size > kMaxSize)
104         return 0;
105 
106     data = d;
107     dataLen = size;
108     compr = (uint8_t *)calloc(1, comprLen);
109     uncompr = (uint8_t *)calloc(1, uncomprLen);
110 
111     test_flush(compr, &comprLen);
112     test_sync(compr, comprLen, uncompr, uncomprLen);
113 
114     free(compr);
115     free(uncompr);
116 
117     /* This function must return 0. */
118     return 0;
119 }
120