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lix/tests/simple.sh
Robert Hensing d038a67bd3 Fix segfault or stack overflow caused by large derivation fields
This removes a dynamic stack allocation, making the derivation
unparsing logic robust against overflows when large strings are
added to a derivation.
Overflow behavior depends on the platform and stack configuration.

For instance, x86_64-linux/glibc behaves as (somewhat) expected:

$ (ulimit -s 20000; nix-instantiate tests/lang/eval-okay-big-derivation-attr.nix)
error: stack overflow (possible infinite recursion)

$ (ulimit -s 40000; nix-instantiate tests/lang/eval-okay-big-derivation-attr.nix)
error: expression does not evaluate to a derivation (or a set or list of those)

However, on aarch64-darwin:

$ nix-instantiate big-attr.nix                                                                                                                                                                                                                                                       ~
zsh: segmentation fault  nix-instantiate big-attr.nix

This indicates a slight flaw in the single stack protection page
approach that is not encountered with normal stack frames.
2022-01-19 15:21:56 +01:00

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source common.sh
drvPath=$(nix-instantiate simple.nix)
test "$(nix-store -q --binding system "$drvPath")" = "$system"
echo "derivation is $drvPath"
outPath=$(nix-store -rvv "$drvPath")
echo "output path is $outPath"
(! [ -w $outPath ])
text=$(cat "$outPath"/hello)
if test "$text" != "Hello World!"; then exit 1; fi
# Directed delete: $outPath is not reachable from a root, so it should
# be deleteable.
nix-store --delete $outPath
(! [ -e $outPath/hello ])
outPath="$(NIX_REMOTE=local?store=/foo\&real=$TEST_ROOT/real-store nix-instantiate --readonly-mode hash-check.nix)"
if test "$outPath" != "/foo/lfy1s6ca46rm5r6w4gg9hc0axiakjcnm-dependencies.drv"; then
echo "hashDerivationModulo appears broken, got $outPath"
exit 1
fi
outPath="$(NIX_REMOTE=local?store=/foo\&real=$TEST_ROOT/real-store nix-instantiate --readonly-mode big-derivation-attr.nix)"
if test "$outPath" != "/foo/xxiwa5zlaajv6xdjynf9yym9g319d6mn-big-derivation-attr.drv"; then
echo "big-derivation-attr.nix hash appears broken, got $outPath. Memory corruption in large drv attr?"
exit 1
fi