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fuzz: port fuzz-parse-attr-line from OSS-Fuzz

Git's fuzz tests are run continuously as part of OSS-Fuzz [1]. Several
additional fuzz tests have been contributed directly to OSS-Fuzz;
however, these tests are vulnerable to bitrot because they are not built
during Git's CI runs, and thus breaking changes are much less likely to
be noticed by Git contributors.

Port one of these tests back to the Git project:
fuzz-parse-attr-line

This test was originally written by Eric Sesterhenn as part of a
security audit of Git [2]. It was then contributed to the OSS-Fuzz repo
in commit c58ac4492 (Git fuzzing: uncomment the existing and add new
targets. (#11486), 2024-02-21) by Jaroslav Lobačevski. I (Josh Steadmon)
have verified with both Eric and Jaroslav that they're OK with moving
this test to the Git project.

[1] https://github.com/google/oss-fuzz
[2] https://ostif.org/wp-content/uploads/2023/01/X41-OSTIF-Gitlab-Git-Security-Audit-20230117-public.pdf

Co-authored-by: Jaroslav Lobačevski <jarlob@gmail.com>
Co-authored-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Josh Steadmon <steadmon@google.com>
Signed-off-by: Taylor Blau <me@ttaylorr.com>

authored by

Eric Sesterhenn
Jaroslav Lobačevski
Josh Steadmon and committed by
Taylor Blau 72686d4e 966253db

+87 -38
unified split
+1
Makefile
··· 2426 2426 FUZZ_OBJS += oss-fuzz/fuzz-date.o 2427 2427 FUZZ_OBJS += oss-fuzz/fuzz-pack-headers.o 2428 2428 FUZZ_OBJS += oss-fuzz/fuzz-pack-idx.o 2429 + FUZZ_OBJS += oss-fuzz/fuzz-parse-attr-line.o 2429 2430 .PHONY: fuzz-objs 2430 2431 fuzz-objs: $(FUZZ_OBJS) 2431 2432
+2 -38
attr.c
··· 259 259 return git_attr_internal(name, strlen(name)); 260 260 } 261 261 262 - /* What does a matched pattern decide? */ 263 - struct attr_state { 264 - const struct git_attr *attr; 265 - const char *setto; 266 - }; 267 - 268 - struct pattern { 269 - const char *pattern; 270 - int patternlen; 271 - int nowildcardlen; 272 - unsigned flags; /* PATTERN_FLAG_* */ 273 - }; 274 - 275 - /* 276 - * One rule, as from a .gitattributes file. 277 - * 278 - * If is_macro is true, then u.attr is a pointer to the git_attr being 279 - * defined. 280 - * 281 - * If is_macro is false, then u.pat is the filename pattern to which the 282 - * rule applies. 283 - * 284 - * In either case, num_attr is the number of attributes affected by 285 - * this rule, and state is an array listing them. The attributes are 286 - * listed as they appear in the file (macros unexpanded). 287 - */ 288 - struct match_attr { 289 - union { 290 - struct pattern pat; 291 - const struct git_attr *attr; 292 - } u; 293 - char is_macro; 294 - size_t num_attr; 295 - struct attr_state state[FLEX_ARRAY]; 296 - }; 297 - 298 262 static const char blank[] = " \t\r\n"; 299 263 300 264 /* Flags usable in read_attr() and parse_attr_line() family of functions. */ ··· 353 317 return ep + strspn(ep, blank); 354 318 } 355 319 356 - static struct match_attr *parse_attr_line(const char *line, const char *src, 357 - int lineno, unsigned flags) 320 + struct match_attr *parse_attr_line(const char *line, const char *src, 321 + int lineno, unsigned flags) 358 322 { 359 323 size_t namelen, num_attr, i; 360 324 const char *cp, *name, *states;
+43
attr.h
··· 240 240 241 241 extern char *git_attr_tree; 242 242 243 + /* 244 + * Exposed for fuzz-testing only. 245 + */ 246 + 247 + /* What does a matched pattern decide? */ 248 + struct attr_state { 249 + const struct git_attr *attr; 250 + const char *setto; 251 + }; 252 + 253 + struct pattern { 254 + const char *pattern; 255 + int patternlen; 256 + int nowildcardlen; 257 + unsigned flags; /* PATTERN_FLAG_* */ 258 + }; 259 + 260 + /* 261 + * One rule, as from a .gitattributes file. 262 + * 263 + * If is_macro is true, then u.attr is a pointer to the git_attr being 264 + * defined. 265 + * 266 + * If is_macro is false, then u.pat is the filename pattern to which the 267 + * rule applies. 268 + * 269 + * In either case, num_attr is the number of attributes affected by 270 + * this rule, and state is an array listing them. The attributes are 271 + * listed as they appear in the file (macros unexpanded). 272 + */ 273 + struct match_attr { 274 + union { 275 + struct pattern pat; 276 + const struct git_attr *attr; 277 + } u; 278 + char is_macro; 279 + size_t num_attr; 280 + struct attr_state state[FLEX_ARRAY]; 281 + }; 282 + 283 + struct match_attr *parse_attr_line(const char *line, const char *src, 284 + int lineno, unsigned flags); 285 + 243 286 #endif /* ATTR_H */
+1
ci/run-build-and-minimal-fuzzers.sh
··· 20 20 date 21 21 pack-headers 22 22 pack-idx 23 + parse-attr-line 23 24 " 24 25 25 26 for fuzzer in $fuzzers; do
+1
oss-fuzz/.gitignore
··· 4 4 fuzz-date 5 5 fuzz-pack-headers 6 6 fuzz-pack-idx 7 + fuzz-parse-attr-line
+39
oss-fuzz/fuzz-parse-attr-line.c
··· 1 + #include "git-compat-util.h" 2 + #include <stddef.h> 3 + #include <stdlib.h> 4 + #include <stdint.h> 5 + #include <string.h> 6 + #include "attr.h" 7 + 8 + int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size); 9 + 10 + int LLVMFuzzerTestOneInput(const uint8_t *data, size_t size) 11 + { 12 + struct match_attr *res; 13 + char *buf; 14 + 15 + buf = malloc(size + 1); 16 + if (!buf) 17 + return 0; 18 + 19 + memcpy(buf, data, size); 20 + buf[size] = 0; 21 + 22 + res = parse_attr_line(buf, "dummy", 0, 0); 23 + 24 + if (res) { 25 + int j; 26 + for (j = 0; j < res->num_attr; j++) { 27 + const char *setto = res->state[j].setto; 28 + if (ATTR_TRUE(setto) || ATTR_FALSE(setto) || 29 + ATTR_UNSET(setto)) 30 + ; 31 + else 32 + free((char *)setto); 33 + } 34 + free(res); 35 + } 36 + free(buf); 37 + 38 + return 0; 39 + }