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Linux toolchain unpack leaves bin/* without execute permission (644) #4900
Description
Summary
After rustup update / toolchain install on Linux, binaries under $RUSTUP_HOME/toolchains/*/bin/ can be installed with mode 644 (-rw-r--r--) instead of 755, causing immediate failures:
error: Permission denied (os error 13)
when invoking cargo, rustc, rustfmt, etc.
Environment
- OS: Linux x86_64 (ext4)
- rustup: 1.29.0 (28d1352 2026-03-05)
- RUSTUP_HOME:
~/.rustup(default) - umask:
022 - Reproduced: 2026-06-08 after
rustup update stable
Steps to reproduce
rustup --version
rustup update stable # or: rustup toolchain install stable
find "$RUSTUP_HOME/toolchains" -path '*/bin/*' -type f ! -perm -111 -print | head
stat -c '%a %n' "$RUSTUP_HOME/toolchains/stable-x86_64-unknown-linux-gnu/bin/cargo"
cargo --version # may fail with os error 13 if 644Expected behaviour
Toolchain binaries under toolchains/*/bin/ are executable (mode includes +x, typically 755 with umask 022).
Actual behaviour
Some or all toolchain bin/* files are 644. The rustup shim itself remains executable; only unpacked toolchain components are affected.
Impact
Breaks CI runners and automation that calls cargo/rustfmt immediately after a toolchain refresh.
Workaround
find "$RUSTUP_HOME/toolchains" -path '*/bin/*' -type f ! -perm -111 -exec chmod +x {} +Additional notes
- Default
~/.rustupwas used (no custom relocation). - Historical toolchains on the same host also showed 644 on
bin/*, suggesting unpack/install rather than backup restore.
Activity
rami3l commentedon Jun 11, 2026
@AlexMikhalev Hello, as far as I know rustup's logic of determining the FS permissions of unpacked files is as follows, based on the
tar_mode:rustup/src/dist/component/package.rs
Lines 330 to 339 in 835392d
This means only a tar with mode
0o6xxin the header can generate0o644files. In other words, it doesn't look like a rustup problem, but a problem with the files it downloads.Is there anything special about your setup in that regard? Are you downloading from a corporate archive of Rust releases? Are you downloading nightlies? Stables should be quite hard to have that problem, otherwise many must have noticed already.