fuzz: add sshconfig_fuzz harness for SSH client config parser#680
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XananasX7 wants to merge 1 commit into
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fuzz: add sshconfig_fuzz harness for SSH client config parser#680XananasX7 wants to merge 1 commit into
XananasX7 wants to merge 1 commit into
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Add a libfuzzer harness covering the SSH client configuration file parser (readconf.c). The parser handles complex directives including Match blocks, ProxyCommand, IdentityFile patterns, and many other options that represent a large attack surface for malformed input. The new harness: - Writes fuzz input to a tempfile and calls read_config_file() - Exercises process_config_line_depth() across all config keywords - Covers Match block evaluation and conditional parsing - Builds against readconf.o, addrmatch.o, misc.o, krl.o Also adds sshconfig_fuzz to the TARGETS list in Makefile.
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Summary
Add a new libfuzzer harness
sshconfig_fuzz.ccthat covers the SSH client configuration file parser (readconf.c).Motivation
The SSH client config parser (
readconf.c, 3957 lines) handles complex and security-sensitive directives:Matchblocks with arbitrary criteriaProxyCommand/ProxyJumpargumentsIdentityFile/CertificateFilepath patternsThis parser is exercised whenever a client reads
~/.ssh/configor/etc/ssh/ssh_config. It is currently not covered by any OSS-Fuzz harness.Changes
regress/misc/fuzz-harness/sshconfig_fuzz.cc: new harness callingread_config_file()with fuzz input written to a tempfile. Exercisesprocess_config_line_depth()across all config keywords and Match blocks.regress/misc/fuzz-harness/Makefile: addsshconfig_fuzztoTARGETSwith correct link deps (readconf.o,addrmatch.o,misc.o,krl.o).Testing
Harness builds cleanly following the existing Makefile pattern. Verified locally that
initialize_options()+read_config_file()is the correct entry point used by the SSH client binary.