From: Evgeny Vereshchagin <evvers@xxxxx> It was found in https://github.com/google/oss-fuzz/pull/4790: ``` Invalid token '' at line 2 of fuzz NEW_FUNC[1/2]: 0x67fff0 in yy_get_previous_state /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1143 NEW_FUNC[2/2]: 0x6803e0 in yy_try_NUL_trans /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1176 ================================================================= ==12==ERROR: AddressSanitizer: heap-use-after-free on address 0x602000007992 at pc 0x000000681800 bp 0x7ffccddee530 sp 0x7ffccddee528 WRITE of size 1 at 0x602000007992 thread T0 SCARINESS: 41 (1-byte-write-heap-use-after-free) #0 0x6817ff in cil_yy_switch_to_buffer /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1315:17 #1 0x6820cc in cil_yy_scan_buffer /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1571:2 #2 0x682662 in cil_lexer_setup /src/selinux/libsepol/src/../cil/src/cil_lexer.l:73:6 #3 0x5cf2ae in cil_parser /src/selinux/libsepol/src/../cil/src/cil_parser.c:220:2 #4 0x56d5e2 in cil_add_file /src/selinux/libsepol/src/../cil/src/cil.c:514:7 #5 0x556e91 in LLVMFuzzerTestOneInput /src/secilc-fuzzer.c:434:7 #6 0x459ab1 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:599:15 #7 0x45a755 in fuzzer::Fuzzer::TryDetectingAMemoryLeak(unsigned char const*, unsigned long, bool) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:675:3 #8 0x45acd9 in fuzzer::Fuzzer::MutateAndTestOne() /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:747:5 #9 0x45b875 in fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:883:5 #10 0x4499fb in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:906:6 #11 0x473a32 in main /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:10 #12 0x7f982296d83f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f) #13 0x41e758 in _start (/out/secilc-fuzzer+0x41e758) DEDUP_TOKEN: cil_yy_switch_to_buffer--cil_yy_scan_buffer--cil_lexer_setup 0x602000007992 is located 2 bytes inside of 4-byte region [0x602000007990,0x602000007994) freed by thread T0 here: #0 0x521ef2 in free /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:127:3 #1 0x56d630 in cil_add_file /src/selinux/libsepol/src/../cil/src/cil.c:526:2 #2 0x556e91 in LLVMFuzzerTestOneInput /src/secilc-fuzzer.c:434:7 #3 0x459ab1 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:599:15 #4 0x458fba in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool, bool*) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:505:3 #5 0x45acc7 in fuzzer::Fuzzer::MutateAndTestOne() /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:745:19 #6 0x45b875 in fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:883:5 #7 0x4499fb in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:906:6 #8 0x473a32 in main /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:10 #9 0x7f982296d83f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f) DEDUP_TOKEN: free--cil_add_file--LLVMFuzzerTestOneInput previously allocated by thread T0 here: #0 0x52215d in malloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:145:3 #1 0x5cecb8 in cil_malloc /src/selinux/libsepol/src/../cil/src/cil_mem.c:39:14 #2 0x56d584 in cil_add_file /src/selinux/libsepol/src/../cil/src/cil.c:510:11 #3 0x556e91 in LLVMFuzzerTestOneInput /src/secilc-fuzzer.c:434:7 #4 0x459ab1 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:599:15 #5 0x458fba in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool, bool*) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:505:3 #6 0x45acc7 in fuzzer::Fuzzer::MutateAndTestOne() /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:745:19 #7 0x45b875 in fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerLoop.cpp:883:5 #8 0x4499fb in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerDriver.cpp:906:6 #9 0x473a32 in main /src/llvm-project/compiler-rt/lib/fuzzer/FuzzerMain.cpp:20:10 #10 0x7f982296d83f in __libc_start_main (/lib/x86_64-linux-gnu/libc.so.6+0x2083f) DEDUP_TOKEN: malloc--cil_malloc--cil_add_file SUMMARY: AddressSanitizer: heap-use-after-free /src/selinux/libsepol/src/../cil/src/cil_lexer.c:1315:17 in cil_yy_switch_to_buffer Shadow bytes around the buggy address: 0x0c047fff8ee0: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fd 0x0c047fff8ef0: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fd 0x0c047fff8f00: fa fa fd fa fa fa fd fa fa fa fd fa fa fa fd fd 0x0c047fff8f10: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fd 0x0c047fff8f20: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fa =>0x0c047fff8f30: fa fa[fd]fa fa fa fd fa fa fa fd fa fa fa fd fa 0x0c047fff8f40: fa fa fd fa fa fa fd fa fa fa fd fa fa fa fd fa 0x0c047fff8f50: fa fa fd fa fa fa fd fd fa fa fd fa fa fa fd fa 0x0c047fff8f60: fa fa fd fd fa fa fd fa fa fa fd fd fa fa fd fa 0x0c047fff8f70: fa fa 00 00 fa fa 02 fa fa fa 02 fa fa fa 00 fa 0x0c047fff8f80: fa fa 03 fa fa fa 00 fa fa fa 03 fa fa fa 00 fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb Shadow gap: cc ==12==ABORTING ``` Signed-off-by: Evgeny Vereshchagin <evvers@xxxxx> --- Patch forwarded from https://github.com/SELinuxProject/selinux/pull/274 --- libsepol/cil/src/cil_parser.c | 1 + 1 file changed, 1 insertion(+) diff --git a/libsepol/cil/src/cil_parser.c b/libsepol/cil/src/cil_parser.c index 585ea7704eeb..a8af1dce2c4b 100644 --- a/libsepol/cil/src/cil_parser.c +++ b/libsepol/cil/src/cil_parser.c @@ -310,6 +310,7 @@ exit: while (!cil_stack_is_empty(stack)) { pop_hll_info(stack, &hll_lineno, &hll_expand); } + cil_lexer_destroy(); cil_stack_destroy(&stack); return SEPOL_ERR; -- 2.29.2
