fix(git): add missing argument injection guards#3545
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ElliotJLT wants to merge 1 commit intomodelcontextprotocol:mainfrom
Open
fix(git): add missing argument injection guards#3545ElliotJLT wants to merge 1 commit intomodelcontextprotocol:mainfrom
ElliotJLT wants to merge 1 commit intomodelcontextprotocol:mainfrom
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…te_branch, git_log, and git_branch
git_diff and git_checkout already reject user-supplied values starting
with '-' to prevent flag injection (even when a malicious ref exists via
filesystem manipulation). The same defense-in-depth pattern was missing
from four other functions:
- git_show: revision parameter passed directly to repo.commit()
- git_create_branch: branch_name and base_branch unchecked
- git_log: start_timestamp and end_timestamp passed to --since/--until
- git_branch: contains and not_contains passed as raw args to repo.git.branch()
Adds the same startswith("-") guards with matching tests for each function.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>
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Summary
git_diffandgit_checkoutalready reject user inputs starting with-to block flag injection attacks — but four other functions lacked the same protection:git_show,git_create_branch,git_log(timestamps), andgit_branch(contains/not_contains)Context
An attacker with filesystem write access (e.g. via
mcp-filesystem) could create malicious git refs like--format=evilunder.git/refs/heads/. Without the leading-dash check, these values would be passed as flags to git commands via GitPython. The existing guards ongit_diffandgit_checkout(+ tests for malicious refs) demonstrate this threat model is already recognised — this PR closes the remaining gaps.Test plan
git_show,git_create_branch,git_log, andgit_branchgit_showrejects malicious refs even when they exist on disk🤖 Generated with Claude Code