i#2356: Add md5 of initial ELF bytes to drsymcache (#2357)

Previously, for Linux drsymcache only checked the library file size to
determine whether the library had changed.  This led to bogus values
and subsequent false positives and worse problems.  Here we add an md5
computed over the first 1024 bytes of the mapped-in library as a
checksum.  It experimentally is enough to distinguish similar libc
versions (which have identical file sizes and top-level ELF headers).

Tested on Debian libc.so.6 2.31-5 vs 2.31-9.

Fixes #2356
2 files changed
tree: 9bce7ce1a0b6782048cda06f5a0e57f1e48286ff
  1. .github/
  2. common/
  3. docs/
  4. drfuzz/
  5. drheapstat/
  6. drltrace/
  7. drmemory/
  8. drstrace/
  9. drsymcache/
  10. drsyscall/
  11. framework/
  12. make/
  13. tests/
  14. third_party/
  15. tools/
  16. umbra/
  17. wininc/
  18. .gitmodules
  19. ACKNOWLEDGEMENTS
  20. CMakeLists.txt
  21. codereview.cmake
  22. CONTRIBUTING.md
  23. CTestConfig.cmake
  24. lgpl-2.1.txt
  25. license.txt
  26. package.cmake
  27. README
  28. README.md
README.md

Dr. Memory: the memory debugger

About Dr. Memory

Dr. Memory is a memory monitoring tool capable of identifying memory-related programming errors such as accesses of uninitialized memory, accesses to unaddressable memory (including outside of allocated heap units and heap underflow and overflow), accesses to freed memory, double frees, memory leaks, and (on Windows) handle leaks, GDI API usage errors, and accesses to un-reserved thread local storage slots.

Dr. Memory operates on unmodified application binaries running on Windows, Linux, Mac, or Android on commodity IA-32, AMD64, and ARM hardware.

Dr. Memory is released under an LGPL license and binary packages are available for download.

Dr. Memory is built on the DynamoRIO dynamic instrumentation tool plaform.

DynamoRIO logo

Dr. Memory Performance

Dr. Memory is faster than comparable tools, including Valgrind, as shown in our CGO 2011 paper Practical Memory Checking with Dr. Memory, where we compare the two tools on Linux on the SPECCPU 2006 benchmark suite:

Performance chart

(Valgrind is unable to run 434.zeusmp and 447.dealII).

Documentation

Documentation is included in the release package. We also maintain a copy for online browsing.

System call tracer for Windows

The Dr. Memory package includes an “strace for Windows” tool called drstrace.

Obtaining help

Dr. Memory has its own discussion list.

To report a bug, use the issue tracker.

See also the Dr. Memory home page: http://drmemory.org/