harden output file handling against race conditions and symlink attacks#4640
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metsw24-max wants to merge 1 commit intofacebook:devfrom
Open
harden output file handling against race conditions and symlink attacks#4640metsw24-max wants to merge 1 commit intofacebook:devfrom
metsw24-max wants to merge 1 commit intofacebook:devfrom
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This change hardens the CLI output file creation path by eliminating race-prone patterns and preventing symlink-based overwrite attacks.
The update replaces the existing unlink-and-recreate workflow with atomic file creation semantics and introduces additional safety checks for output file handling
Replace non-atomic
unlink() + open()pattern with atomic open usingO_EXCLfor non-overwrite modePrevent symlink traversal during output file creation using
O_NOFOLLOWAdd
O_CLOEXECto reduce file descriptor leakage across exec boundariesIntroduce explicit handling of
EEXISTandELOOPfor clearer and safer error reporting