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LibTextCodec: Heap buffer overflow in UTF16-BE decoderΒ #5769

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@Lubrsi

Description

@Lubrsi

With just one byte: 0xa
Trace:

=================================================================
==35012==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x6020000000f1 at pc 0x000000568e44 bp 0x7ffd23defd30 sp 0x7ffd23defd28
READ of size 1 at 0x6020000000f1 thread T0
    #0 0x568e43 in TextCodec::UTF16BEDecoder::to_utf8(AK::StringView const&) /home/lukew/Desktop/serenity-project/serenity/build/../Userland/Libraries/LibTextCodec/Decoder.cpp:187:44
    #1 0x55d55b in LLVMFuzzerTestOneInput /home/lukew/Desktop/serenity-project/serenity/build/../Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder.cpp:36:14
    #2 0x4656f1 in fuzzer::Fuzzer::ExecuteCallback(unsigned char const*, unsigned long) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x4656f1)
    #3 0x464e35 in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool*) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x464e35)
    #4 0x467611 in fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x467611)
    #5 0x467ab9 in fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x467ab9)
    #6 0x45678e in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x45678e)
    #7 0x47f5d2 in main (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x47f5d2)
    #8 0x7f050ac3e0b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16
    #9 0x42b52d in _start (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x42b52d)

0x6020000000f1 is located 0 bytes to the right of 1-byte region [0x6020000000f0,0x6020000000f1)
allocated by thread T0 here:
    #0 0x52b25d in malloc (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x52b25d)
    #1 0x43f917 in operator new(unsigned long) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x43f917)
    #2 0x464e35 in fuzzer::Fuzzer::RunOne(unsigned char const*, unsigned long, bool, fuzzer::InputInfo*, bool*) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x464e35)
    #3 0x467611 in fuzzer::Fuzzer::ReadAndExecuteSeedCorpora(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x467611)
    #4 0x467ab9 in fuzzer::Fuzzer::Loop(std::__Fuzzer::vector<fuzzer::SizedFile, fuzzer::fuzzer_allocator<fuzzer::SizedFile> >&) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x467ab9)
    #5 0x45678e in fuzzer::FuzzerDriver(int*, char***, int (*)(unsigned char const*, unsigned long)) (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x45678e)
    #6 0x47f5d2 in main (/home/lukew/Desktop/serenity-project/serenity/build/Meta/Lagom/Fuzzers/FuzzUTF16BEDecoder+0x47f5d2)
    #7 0x7f050ac3e0b2 in __libc_start_main /build/glibc-eX1tMB/glibc-2.31/csu/../csu/libc-start.c:308:16

SUMMARY: AddressSanitizer: heap-buffer-overflow /home/lukew/Desktop/serenity-project/serenity/build/../Userland/Libraries/LibTextCodec/Decoder.cpp:187:44 in TextCodec::UTF16BEDecoder::to_utf8(AK::StringView const&)
Shadow bytes around the buggy address:
  0x0c047fff7fc0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c047fff7fd0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c047fff7fe0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c047fff7ff0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
  0x0c047fff8000: fa fa 00 00 fa fa 00 fa fa fa 00 fa fa fa 00 fa
=>0x0c047fff8010: fa fa fd fa fa fa 00 fa fa fa 01 fa fa fa[01]fa
  0x0c047fff8020: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8030: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8040: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8050: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa
  0x0c047fff8060: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 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
==35012==ABORTING
MS: 0 ; base unit: 0000000000000000000000000000000000000000
0xa,
\x0a
artifact_prefix='./'; Test unit written to ./crash-adc83b19e793491b1c6ea0fd8b46cd9f32e592fc
Base64: Cg==

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