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path: root/src/env/__init_security.c
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2012-10-07clean up and refactor program initializationRich Felker1-12/+7
the code in __libc_start_main is now responsible for parsing auxv, rather than duplicating the parsing all over the place. this should shave off a few cycles and some code size. __init_libc is left as an external-linkage function despite the fact that it could be static, to prevent it from being inlined and permanently wasting stack space when main is called. a few other minor changes are included, like eliminating per-thread ssp canaries (they were likely broken when combined with certain dlopen usages, and completely unnecessary) and some other unnecessary checks. since this code gets linked into every program, it should be as small and simple as possible.
2012-07-27save AT_HWCAP from auxv for subsequent use in machine-specific codeRich Felker1-0/+1
it's expected that this will be needed/useful only in asm, so I've given it its own symbol that can be addressed in pc-relative ways from asm rather than adding a field in the __libc structure which would require hard-coding the offset wherever it's used.
2012-06-14direct syscall to open in __init_security needs O_LARGEFILERich Felker1-1/+1
it probably does not matter for /dev/null, but this should be done consistently anyway.
2012-05-10fix missing static (namespace clash)Rich Felker1-1/+1
2012-05-03overhaul SSP support to use a real canaryRich Felker1-2/+4
pthread structure has been adjusted to match the glibc/GCC abi for where the canary is stored on i386 and x86_64. it will need variants for other archs to provide the added security of the canary's entropy, but even without that it still works as well as the old "minimal" ssp support. eventually such changes will be made anyway, since they are also needed for GCC/C11 thread-local storage support (not yet implemented). care is taken not to attempt initializing the thread pointer unless the program actually uses SSP (by reference to __stack_chk_fail).
2012-04-24first attempt at enabling stack protector supportRich Felker1-0/+7
the code is written to pre-init the thread pointer in static linked programs that pull in __stack_chk_fail or dynamic-linked programs that lookup the symbol. no explicit canary is set; the canary will be whatever happens to be in the thread structure at the offset gcc hard-coded. this can be improved later.
2011-08-23security hardening: ensure suid programs have valid stdin/out/errRich Felker1-0/+26
this behavior (opening fds 0-2 for a suid program) is explicitly allowed (but not required) by POSIX to protect badly-written suid programs from clobbering files they later open. this commit does add some cost in startup code, but the availability of auxv and the security flag will be useful elsewhere in the future. in particular auxv is needed for static-linked vdso support, which is still waiting to be committed (sorry nik!)