psm: add .note.GNU-stack section as executable stack is not needed #136
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symphorien
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| @@ -0,0 +1,3 @@ | |||
| #if defined(__linux__) && defined(__ELF__) | |||
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Probably should be checking for __gnu_linux__ or __GNUC__ (which despite having "C" in its name) is defined when compiling assembly and is going to be specific for gnu targets where this matters.
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Additionally, lets rename the file to be more self-descriptive (e.g. gnu_stack_note.s)
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gentoo wiki recommends it this way. https://wiki.gentoo.org/wiki/Hardened/GNU_stack_quickstart#Patching
I suspect it covers the case where the assembler is not gnu but the linker is (as this note is directed to the linker, as far as I understand)
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Additionally, lets rename the file to be more self-descriptive (e.g. gnu_stack_note.s)
Done
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Hm, having done some more research, I think this check could drop the linux check altogether and just condition on just the
defined(__ELF__)
https://github.com/llvm/llvm-project/blob/66df6cceea001a2082bc78678305a86b9bb29ecb/llvm/lib/MC/MCAsmInfoELF.cpp#L30-L37 does not emit this section on solaris, but psm does not need to worry too much about creating that one superfluous mini-section on targets that might not use it.
On GNU/Linux, when linking an executable comprising a static library created by cargo because Cargo.toml contains crate-type = ["staticlib"] the linker outputs the following warning: ``` /nix/store/dc9vaz50jg7mibk9xvqw5dqv89cxzla3-binutils-2.44/bin/ld: warning: 4f9a91766097c4c5-x86_64.o: missing .note.GNU-stack section implies executable stack /nix/store/dc9vaz50jg7mibk9xvqw5dqv89cxzla3-binutils-2.44/bin/ld: NOTE: This behaviour is deprecated and will be removed in a future version of the linker ``` (where 4f9a91766097c4c5-x86_64.o is the object corresponding to psm/src/arch/x86_64.s) Add the note requested by the linker. For some reason, executables linked directly by rustc do not seem affected. I only observed this with a c++ project linking a rust static library comprising psm (lnav).
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can you restart the job that failed due to a timeout? It seems the button to do it is privileged. |
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On GNU/Linux, when linking an executable comprising psm in a static library created by cargo because Cargo.toml contains
crate-type = ["staticlib"], the linker outputs the following warning:(where 4f9a91766097c4c5-x86_64.o is the object corresponding to psm/src/arch/x86_64.s)
Add the note requested by the linker.
For some reason, executables linked directly by rustc do not seem affected. I only observed this with a c++ project linking a rust static library comprising psm (lnav).
Note that I'm quite out of my depth here, and that I have only tested on x86_64-linux-gnu. I expect that a note will not be problematic with non-gnu toolchains, which should ignore it.