On Sun, Dec 6, 2020 at 11:31 PM Nicolas Iooss <nicolas.iooss@xxxxxxx> wrote: > > 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 Oops, I forgot to Cc the orginal author of the patch. Adding him now, with my: Acked-by: Nicolas Iooss <nicolas.iooss@xxxxxxx> Nicolas > --- > 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 >
