/src/gzio_fuzzer.c

Source (jump to first uncovered line)
/********************************************************************************
 * Copyright 2025 Google LLC
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 *******************************************************************************/
#include <stdio.h>
#include <stddef.h>
#include <stdint.h>
#include <string.h>
#include <assert.h>
#include <stdlib.h>
#include <inttypes.h>
#include "zlib.h"

#undef gzgetc

int LLVMFuzzerTestOneInput(const uint8_t *data, size_t dataLen) {

    gzFile file;
    char fname[] = "gzio.XXXXXX";
    close(mkstemp(fname));
    unsigned mode_sz = (dataLen ? (--dataLen, *data++) | 2 : 8) & 0xF;
    char mode[mode_sz];
    memcpy(mode, data, dataLen >= mode_sz ? mode_sz - 1: dataLen);
    mode[mode_sz - 1] = 0;
    file = gzopen(fname, mode);

    /* Chain I/O operations on a file opened with random mode the nature of the
     * operation and their operand are controlled by the fuzzer
     */
    int op_count = 2; //< Number of operations chained.
    while(op_count--) {
      switch((--dataLen, (*data)%19)) {
        case 0: {
          char c = dataLen ? (--dataLen, (char)*data++) : 'c';
          if(gzputc(file, c) < 0) {
            goto exit;
          }
          break;
        }
        case 1: {
          unsigned sz = dataLen ? ((--dataLen, *data++)&0xF) + 1 : 8;
          char input[sz];
          memcpy(input, data, dataLen >= sz ? sz - 1: dataLen);
          input[sz - 1] = 0;
          if(gzputs(file, input) < 0)
            goto exit;
          break;
        }
        case 2: {
          unsigned sz = dataLen ? ((--dataLen, *data++)&0xF) + 1 : 8;
          unsigned nitems = dataLen ? ((--dataLen, *data++)&0xF) + 1 : 8;
          unsigned count = sz * nitems;
          char input[count];
          memcpy(input, data, dataLen >= count ? count - 1: dataLen);
          input[count - 1] = 0;
          if(gzfwrite(input, sz, nitems, file) <= 0)
            goto exit;
          break;
        }
        case 3: {
          unsigned sz = dataLen ? (--dataLen, *data++) : 8;
          char uncompr[sz];
          if(gzread(file, uncompr, sz) < 0)
            goto exit;
          break;
        }
        case 4: {
          int whences[5] = {SEEK_CUR, SEEK_SET, SEEK_END, 18};
          int whence = dataLen ? (--dataLen, whences[(*data++)%6]) : SEEK_CUR;
          long offset = dataLen >= sizeof(long) ? (*(long*)data &0xFF) + 1: 1L;
          if(gzseek(file, offset, whence) < 0)
            goto exit;
          break;
        }
        case 5:
          gztell(file);
          break;
        case 6:
          gzgetc(file);
          break;
        case 7: {
          char c = dataLen ? (--dataLen, (char)*data++) : 'c';
          if(gzungetc(c, file) < 0)
            goto exit;
          break;
        }
        case 8: {
          unsigned sz = dataLen ? (--dataLen, *data++) : 8;
          char uncompr[sz];
          if(gzgets(file, uncompr, sz) < 0)
            goto exit;
          break;
        }
        case 9: {
          int level = dataLen ? (--dataLen, *data++) : 1;
          int strat = dataLen ? (--dataLen, *data++) : 2;
          if(gzsetparams(file, level, strat) < 0)
            goto exit;
          break;
        }
        case 10: {
          int flush = dataLen ? (--dataLen, *data++) : 1;
          gzflush(file, flush); break;
        }
        case 11: {
          static const char formats [][4] = { "%d", "%f", "%c", "%s" };
          int nformat = dataLen ? (--dataLen, *data++)%5 : 1;
          switch(nformat) {
            case 0: {
              int value = dataLen >= sizeof(int) ? *(int*)data : 1;
              gzprintf(file, formats[nformat], value);
              break;
            }
            case 1: {
              float value = dataLen >= sizeof(float) ? *(float*)data : 1;
              gzprintf(file, formats[nformat], value);
              break;
            }
            case 2: {
              char value = dataLen >= sizeof(char) ? *(char*)data : 1;
              gzprintf(file, formats[nformat], value);
              break;
            }
            case 3: {
             unsigned sz = dataLen ? ((--dataLen, *data++)&0xF)+1 : 8;
             char input[sz];
             memcpy(input, data, dataLen >= sz ? sz - 1: dataLen);
             input[sz - 1] = 0;
             gzprintf(file, formats[nformat], input);
             break;
            }
            default: {
             unsigned sz = dataLen ? ((--dataLen, *data++)&0xF)+1 : 8;
             char input[sz] = {};
             memcpy(input, data, dataLen >= sz ? sz - 1: dataLen);
             for(int i = 0; i < sz - 1; ++i)
               if(input[i] == '%') input[i] = '!';
             gzprintf(file, input);
             break;
            }
          };
          break;
        }
        case 12: {
          gzoffset(file);
          break;
        }
        case 13: {
          gzrewind(file);
          break;
        }
        case 14: {
          gzeof(file);
          break;
        }
        case 15: {
          gzdirect(file);
          break;
        }
        case 16: {
          unsigned sz = dataLen ? ((--dataLen, *data++))|1 : 128;
          if(gzbuffer(file, sz) <0)
            goto exit;
          break;
        }
        case 17: {
          int errnum;
          gzerror(file, &errnum);
          break;
        }
        case 18: {
          gzclearerr(file);
          break;
        }
      }
    }
    gzclose(file);
    remove(fname);
  return 0;
exit:
    gzclose(file);
    remove(fname);
  return -1;
}

Line	Count	Source (jump to first uncovered line)
1		/********************************************************************************
2		* Copyright 2025 Google LLC
3		*
4		* Licensed under the Apache License, Version 2.0 (the "License");
5		* you may not use this file except in compliance with the License.
6		* You may obtain a copy of the License at
7		*
8		* http://www.apache.org/licenses/LICENSE-2.0
9		*
10		* Unless required by applicable law or agreed to in writing, software
11		* distributed under the License is distributed on an "AS IS" BASIS,
12		* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13		* See the License for the specific language governing permissions and
14		* limitations under the License.
15		*
16		*******************************************************************************/
17		#include <stdio.h>
18		#include <stddef.h>
19		#include <stdint.h>
20		#include <string.h>
21		#include <assert.h>
22		#include <stdlib.h>
23		#include <inttypes.h>
24		#include "zlib.h"
25
26		#undef gzgetc
27
28	1.37k	int LLVMFuzzerTestOneInput(const uint8_t *data, size_t dataLen) {
29
30	1.37k	gzFile file;
31	1.37k	char fname[] = "gzio.XXXXXX";
32	1.37k	close(mkstemp(fname));
33	1.37k	unsigned mode_sz = (dataLen ? (--dataLen, *data++) \| 2 : 8) & 0xF;
34	1.37k	char mode[mode_sz];
35	1.37k	memcpy(mode, data, dataLen >= mode_sz ? mode_sz - 1: dataLen);
36	1.37k	mode[mode_sz - 1] = 0;
37	1.37k	file = gzopen(fname, mode);
38
39		/* Chain I/O operations on a file opened with random mode the nature of the
40		* operation and their operand are controlled by the fuzzer
41		*/
42	1.37k	int op_count = 2; //< Number of operations chained.
43	3.68k	while(op_count--) {
44	2.57k	switch((--dataLen, (*data)%19)) {
45	97	case 0: {
46	97	char c = dataLen ? (--dataLen, (char)*data++) : 'c';
47	97	if(gzputc(file, c) < 0) {
48	60	goto exit;
49	60	}
50	37	break;
51	97	}
52	108	case 1: {
53	108	unsigned sz = dataLen ? ((--dataLen, *data++)&0xF) + 1 : 8;
54	108	char input[sz];
55	108	memcpy(input, data, dataLen >= sz ? sz - 1: dataLen);
56	108	input[sz - 1] = 0;
57	108	if(gzputs(file, input) < 0)
58	44	goto exit;
59	64	break;
60	108	}
61	827	case 2: {
62	827	unsigned sz = dataLen ? ((--dataLen, *data++)&0xF) + 1 : 8;
63	827	unsigned nitems = dataLen ? ((--dataLen, *data++)&0xF) + 1 : 8;
64	827	unsigned count = sz * nitems;
65	827	char input[count];
66	827	memcpy(input, data, dataLen >= count ? count - 1: dataLen);
67	827	input[count - 1] = 0;
68	827	if(gzfwrite(input, sz, nitems, file) <= 0)
69	29	goto exit;
70	798	break;
71	827	}
72	798	case 3: {
73	50	unsigned sz = dataLen ? (--dataLen, *data++) : 8;
74	50	char uncompr[sz];
75	50	if(gzread(file, uncompr, sz) < 0)
76	22	goto exit;
77	28	break;
78	50	}
79	233	case 4: {
80	233	int whences[5] = {SEEK_CUR, SEEK_SET, SEEK_END, 18};
81	233	int whence = dataLen ? (--dataLen, whences[(*data++)%6]) : SEEK_CUR;
82	233	long offset = dataLen >= sizeof(long) ? ((long)data &0xFF) + 1: 1L;
83	233	if(gzseek(file, offset, whence) < 0)
84	26	goto exit;
85	207	break;
86	233	}
87	207	case 5:
88	128	gztell(file);
89	128	break;
90	65	case 6:
91	65	gzgetc(file);
92	65	break;
93	60	case 7: {
94	60	char c = dataLen ? (--dataLen, (char)*data++) : 'c';
95	60	if(gzungetc(c, file) < 0)
96	41	goto exit;
97	19	break;
98	60	}
99	89	case 8: {
100	89	unsigned sz = dataLen ? (--dataLen, *data++) : 8;
101	89	char uncompr[sz];
102	89	if(gzgets(file, uncompr, sz) < 0)
103	0	goto exit;
104	89	break;
105	89	}
106	163	case 9: {
107	163	int level = dataLen ? (--dataLen, *data++) : 1;
108	163	int strat = dataLen ? (--dataLen, *data++) : 2;
109	163	if(gzsetparams(file, level, strat) < 0)
110	28	goto exit;
111	135	break;
112	163	}
113	135	case 10: {
114	72	int flush = dataLen ? (--dataLen, *data++) : 1;
115	72	gzflush(file, flush); break;
116	163	}
117	347	case 11: {
118	347	static const char formats [][4] = { "%d", "%f", "%c", "%s" };
119	347	int nformat = dataLen ? (--dataLen, *data++)%5 : 1;
120	347	switch(nformat) {
121	38	case 0: {
122	38	int value = dataLen >= sizeof(int) ? (int)data : 1;
123	38	gzprintf(file, formats[nformat], value);
124	38	break;
125	0	}
126	86	case 1: {
127	86	float value = dataLen >= sizeof(float) ? (float)data : 1;
128	86	gzprintf(file, formats[nformat], value);
129	86	break;
130	0	}
131	31	case 2: {
132	31	char value = dataLen >= sizeof(char) ? (char)data : 1;
133	31	gzprintf(file, formats[nformat], value);
134	31	break;
135	0	}
136	58	case 3: {
137	58	unsigned sz = dataLen ? ((--dataLen, *data++)&0xF)+1 : 8;
138	58	char input[sz];
139	58	memcpy(input, data, dataLen >= sz ? sz - 1: dataLen);
140	58	input[sz - 1] = 0;
141	58	gzprintf(file, formats[nformat], input);
142	58	break;
143	0	}
144	134	default: {
145	134	unsigned sz = dataLen ? ((--dataLen, *data++)&0xF)+1 : 8;
146	134	char input[sz] = {};
147	134	memcpy(input, data, dataLen >= sz ? sz - 1: dataLen);
148	1.12k	for(int i = 0; i < sz - 1; ++i)
149	993	if(input[i] == '%') input[i] = '!';
150	134	gzprintf(file, input);
151	134	break;
152	0	}
153	347	};
154	347	break;
155	347	}
156	28	case 12: {
157	28	gzoffset(file);
158	28	break;
159	347	}
160	38	case 13: {
161	38	gzrewind(file);
162	38	break;
163	347	}
164	17	case 14: {
165	17	gzeof(file);
166	17	break;
167	347	}
168	29	case 15: {
169	29	gzdirect(file);
170	29	break;
171	347	}
172	186	case 16: {
173	186	unsigned sz = dataLen ? ((--dataLen, *data++))\|1 : 128;
174	186	if(gzbuffer(file, sz) <0)
175	19	goto exit;
176	167	break;
177	186	}
178	167	case 17: {
179	22	int errnum;
180	22	gzerror(file, &errnum);
181	22	break;
182	186	}
183	19	case 18: {
184	19	gzclearerr(file);
185	19	break;
186	186	}
187	2.57k	}
188	2.57k	}
189	1.10k	gzclose(file);
190	1.10k	remove(fname);
191	1.10k	return 0;
192	269	exit:
193	269	gzclose(file);
194	269	remove(fname);
195	269	return -1;
196	1.37k	}

Coverage Report

Created: 2025-07-18 06:42