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Remove somewhat obvious comment about executing attacker-controlled programs. Be more clear the examples are not exhaustive.
…affleLapkin explicit tail calls: support indirect arguments tracking issue: rust-lang#112788 After discussion in rust-lang#144855, I was wrong and it is actually possible to support tail calls with `PassMode::Indirect { on_stack: false, .. }` arguments. Normally an indirect argument with `on_stack: false` would be passed as a pointer into the caller's stack frame. For tail calls, that would be unsound, because the caller's stack frame is overwritten by the callee's stack frame. Therefore we store the argument for the callee in the corresponding caller's slot. Because guaranteed tail calls demand that the caller's signature matches the callee's, the corresponding slot has the correct type. To handle cases like the one below, the tail call arguments must first be copied to a temporary, and can only then be copied to the caller's argument slots. ```rust // A struct big enough that it is not passed via registers. pub struct Big([u64; 4]); fn swapper(a: Big, b: Big) -> (Big, Big) { become swapper_helper(b, a); } ``` --- I'm not really familiar with MIR and what tricks/helpers we have, so I'm just cobbling this together. Hopefully we can arrive at something more elegant.
Stop using `LinkedGraph` in `lexical_region_resolve` There are only two users of the older `LinkedGraph` data structure, and this is one. It turns out that this diagnostic-related code doesn't need any non-trivial graph operations (since it does its own graph traversal); it just needs the ability to get a list of in-edges or out-edges (constraints) for any particular node. That's easy enough to do with a simple custom data structure. Inspired by rust-lang#152621, which wants to make changes to `LinkedGraph` that wouldn't make sense for this use-site.
…iper Improved security section in rustdoc for `current_exe` A few improvements to the security section of the docs about `current_exe` 0. The explanatory link <https://vulners.com/securityvulns/SECURITYVULNS:DOC:22183> is ~~broken~~ not directly very helpful in understanding the risk. 1. It basically previously says to never trust the result, which is IMO too pessimistic to be helpful. It's worth understanding the behavior but if you have a use case to re-exec the current program, which is not uncommon, this is a reasonable way to do it. 2. The particular risk is about setuid/setgid processes that shouldn't fully trust the user that spawned them. 3. IMO the most important risk with this function is that the invoker can control argv and PATH, so I made this more explicit. (Many unixes, including Linux, don't rely on them in the implementation, but some do.) 4. The previous text about TOCTOU and races is IMO not really coherent: if an attacker can write to the location where you're going to re-exec, they can fundamentally control what program is executed. They don't need to race with your execution of current_exe, and there is no up-front check. 5. Briefly explain the pattern of CVE-2009-1894: on Linux, depending on system configuration, an attacker who can create hardlinks to the executable can potentially control `/proc/self/exe`. On modern Linux this should normally require permission to write to the executable. I did some web research for "argv0 vulnerability" and similar terms and didn't find anything else we should be documenting here. (There are issues about argc=0 but those should be prevented by memory safety in Rust.) I found what the link seemed to be pointing to in <https://vulners.com/cve/CVE-2009-1894>, which talks about confusing a setuid program by creating a hardlink to its exe. I think this is in very particular circumstances something people should still be concerned about: a setuid program on a machine with `fs.protected_hardlinks = 0`. I don't think this justifies warning people not to use the function at all. cc @mgeisler
…, r=GuillaumeGomez Remove mutation from macro path URL construction Resolves the `FIXME` in `generate_macro_def_id_path`. The old code mutated `path` to build the URL — popping the macro name, pushing an interned filename, then restoring the original at the end. None of that was necessary. A slice pattern gives us `module_path` and `last` without touching the original, and `push_fmt(format_args!(...))` writes the filename directly into the URL builder, same as `make_href` already does. Also tightened the error guards: the original `path.len() < 2` is now two distinct checks with messages that describe the actual failure (empty path vs. single-element path missing the crate prefix). r? @GuillaumeGomez
…oboet Recover feature lang_items for emscripten Fixes rust-lang#152469 (comment)
…r=petrochenkov Print path root when printing path Extracted from rust-lang#152996. r? petrochenkov
…rcote Work around a false `err.emit();` type error in rust-analyzer For whatever reason, rust-analyzer doesn't see that these calls to `err.emit();` are diverging, so the trailing semicolon makes r-a complain about a type mismatch between `()` and some other type. Removing the trailing semicolon makes no functional difference (because the emit still unwinds the stack), but seems to be enough to allow rust-analyzer to see that emitting an error returns `!` in these cases, which silences the false error.
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Rollup of 7 pull requests Successful merges: - #151143 (explicit tail calls: support indirect arguments) - #153012 (Stop using `LinkedGraph` in `lexical_region_resolve`) - #150828 (Improved security section in rustdoc for `current_exe`) - #153117 (Remove mutation from macro path URL construction) - #153128 (Recover feature lang_items for emscripten) - #153138 (Print path root when printing path) - #153159 (Work around a false `err.emit();` type error in rust-analyzer)
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Successful merges:
LinkedGraphinlexical_region_resolve#153012 (Stop usingLinkedGraphinlexical_region_resolve)current_exe#150828 (Improved security section in rustdoc forcurrent_exe)err.emit();type error in rust-analyzer #153159 (Work around a falseerr.emit();type error in rust-analyzer)r? @ghost
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