Issue 60887 in oss-fuzz: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib

Issue 60887 in oss-fuzz: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib

[ClusterFuzz-External via monorail]

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Status: New
Owner: ----
CC: elfut...@sourceware.org, da...@adalogics.com, evv...@gmail.com, izzeem@google.com 
Labels: ClusterFuzz Stability-Memory-AddressSanitizer Reproducible Stability-Memory-LeakSanitizer Engine-libfuzzer OS-Linux Proj-elfutils Reported-2023-07-27
Type: Bug

New issue 60887 by ClusterFuzz-External: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=60887

Detailed Report: https://oss-fuzz.com/testcase?key=4651173658099712

Project: elfutils
Fuzzing Engine: libFuzzer
Fuzz Target: fuzz-libelf
Job Type: libfuzzer_asan_elfutils
Platform Id: linux

Crash Type: Direct-leak
Crash Address: 
Crash State:
  __libelf_decompress_zlib
  __libelf_decompress_elf
  get_zdata
  
Sanitizer: address (ASAN)

Regressed: https://oss-fuzz.com/revisions?job=libfuzzer_asan_elfutils&range=202203161800:202203170000

Reproducer Testcase: https://oss-fuzz.com/download?testcase_id=4651173658099712

Issue filed automatically.

See https://google.github.io/oss-fuzz/advanced-topics/reproducing for instructions to reproduce this bug locally.
When you fix this bug, please
  * mention the fix revision(s).
  * state whether the bug was a short-lived regression or an old bug in any stable releases.
  * add any other useful information.
This information can help downstream consumers.

If you need to contact the OSS-Fuzz team with a question, concern, or any other feedback, please file an issue at https://github.com/google/oss-fuzz/issues. Comments on individual Monorail issues are not monitored.

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Re: Issue 60887 in oss-fuzz: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib

[Mark Wielaard]

Hi Evgeny,

Do you happen to know what clusterfuzz is trying to tell us?  The
stack trace is not detailed enough to understand what is going on.
The reproducer is a corrupt ELF file with no indication of what code
is being run on it. And the detailed report is not accessible (it
seems to require a google or github account to login).

Thanks,

Mark

On Thu, Jul 27, 2023 at 01:44:24PM -0700, ClusterFuzz-External via monorail via Elfutils-devel wrote:
> Status: New
> Owner: ----
> CC: elfut...@sourceware.org, da...@adalogics.com, evv...@gmail.com, izzeem@google.com 
> Labels: ClusterFuzz Stability-Memory-AddressSanitizer Reproducible Stability-Memory-LeakSanitizer Engine-libfuzzer OS-Linux Proj-elfutils Reported-2023-07-27
> Type: Bug
> 
> New issue 60887 by ClusterFuzz-External: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib
> https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=60887
> 
> Detailed Report: https://oss-fuzz.com/testcase?key=4651173658099712
> 
> Project: elfutils
> Fuzzing Engine: libFuzzer
> Fuzz Target: fuzz-libelf
> Job Type: libfuzzer_asan_elfutils
> Platform Id: linux
> 
> Crash Type: Direct-leak
> Crash Address: 
> Crash State:
>   __libelf_decompress_zlib
>   __libelf_decompress_elf
>   get_zdata
>   
> Sanitizer: address (ASAN)
> 
> Regressed: https://oss-fuzz.com/revisions?job=libfuzzer_asan_elfutils&range=202203161800:202203170000
> 
> Reproducer Testcase: https://oss-fuzz.com/download?testcase_id=4651173658099712
> 
> Issue filed automatically.
> 
> See https://google.github.io/oss-fuzz/advanced-topics/reproducing for instructions to reproduce this bug locally.
> When you fix this bug, please
>   * mention the fix revision(s).
>   * state whether the bug was a short-lived regression or an old bug in any stable releases.
>   * add any other useful information.
> This information can help downstream consumers.
> 
> If you need to contact the OSS-Fuzz team with a question, concern, or any other feedback, please file an issue at https://github.com/google/oss-fuzz/issues. Comments on individual Monorail issues are not monitored.
> 
> -- 
> You received this message because:
>   1. You were specifically CC'd on the issue
> 
> You may adjust your notification preferences at:
> https://bugs.chromium.org/hosting/settings
> 
> Reply to this email to add a comment.

Issue 60887 in oss-fuzz: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib

[evv… via monorail]

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Comment #1 on issue 60887 by evv...@gmail.com: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=60887#c1

The full backtrace is
```
==178009==ERROR: LeakSanitizer: detected memory leaks
Direct leak of 1 byte(s) in 1 object(s) allocated from:
    #0 0x52efd6 in __interceptor_malloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:69:3
    #1 0x57a228 in __libelf_decompress_zlib /src/elfutils/libelf/elf_compress.c:370:19
    #2 0x57a987 in __libelf_decompress /src/elfutils/libelf/elf_compress.c:440:12
    #3 0x57a987 in __libelf_decompress_elf /src/elfutils/libelf/elf_compress.c:500:7
    #4 0x57629f in get_zdata /src/elfutils/libelf/elf_strptr.c:45:17
    #5 0x575c5e in elf_strptr /src/elfutils/libelf/elf_strptr.c:135:38
    #6 0x56c5b3 in fuzz_logic_one /src/fuzz-libelf.c:40:26
    #7 0x56cc7f in LLVMFuzzerTestOneInput /src/fuzz-libelf.c:88:3
```

I haven't figured out how to trigger that memory leak without the fuzz target
but as far as I can tell `fuzz_logic_one` was inspired by the elfgetzdata test in
the sense that it calls elf_nextscn/elf_strptr/elf_compress.

The code triggering the memory leak is
https://github.com/google/oss-fuzz/blob/24328c88fd610decaf311020ffc7073aec1db252/projects/elfutils/fuzz-libelf.c#L27C6-L27C20

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Re: Issue 60887 in oss-fuzz: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib

[Mark Wielaard]

Hi,

On Sat, Jul 29, 2023 at 03:00:49PM -0700, evv… via monorail via Elfutils-devel wrote:
> 
> Comment #1 on issue 60887 by evv...@gmail.com: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib
> https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=60887#c1
> 
> The full backtrace is
> ```
> ==178009==ERROR: LeakSanitizer: detected memory leaks
> Direct leak of 1 byte(s) in 1 object(s) allocated from:
>     #0 0x52efd6 in __interceptor_malloc /src/llvm-project/compiler-rt/lib/asan/asan_malloc_linux.cpp:69:3
>     #1 0x57a228 in __libelf_decompress_zlib /src/elfutils/libelf/elf_compress.c:370:19
>     #2 0x57a987 in __libelf_decompress /src/elfutils/libelf/elf_compress.c:440:12
>     #3 0x57a987 in __libelf_decompress_elf /src/elfutils/libelf/elf_compress.c:500:7
>     #4 0x57629f in get_zdata /src/elfutils/libelf/elf_strptr.c:45:17
>     #5 0x575c5e in elf_strptr /src/elfutils/libelf/elf_strptr.c:135:38
>     #6 0x56c5b3 in fuzz_logic_one /src/fuzz-libelf.c:40:26
>     #7 0x56cc7f in LLVMFuzzerTestOneInput /src/fuzz-libelf.c:88:3
> ```
> 
> I haven't figured out how to trigger that memory leak without the fuzz target
> but as far as I can tell `fuzz_logic_one` was inspired by the elfgetzdata test in
> the sense that it calls elf_nextscn/elf_strptr/elf_compress.
> 
> The code triggering the memory leak is
> https://github.com/google/oss-fuzz/blob/24328c88fd610decaf311020ffc7073aec1db252/projects/elfutils/fuzz-libelf.c#L27C6-L27C20

Thanks, I can replicate it with that and valgrind.  The issue is when
elf_strptr has (partially) uncompressed the section data (to read the
uncompressed string), the program never requests the (uncompressed)
section data, but does (re)compress it.

Working on a fix.

Cheers,

Mark

Issue 60887 in oss-fuzz: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib

[ClusterFuzz-External via monorail]

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Updates:
	Labels: ClusterFuzz-Verified
	Status: Verified

Comment #2 on issue 60887 by ClusterFuzz-External: elfutils:fuzz-libelf: Direct-leak in __libelf_decompress_zlib
https://bugs.chromium.org/p/oss-fuzz/issues/detail?id=60887#c2

ClusterFuzz testcase 4651173658099712 is verified as fixed in https://oss-fuzz.com/revisions?job=libfuzzer_asan_elfutils&range=202308021200:202308021800

If this is incorrect, please file a bug on https://github.com/google/oss-fuzz/issues/new

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