From: Harmen Stoppels <me@harmenstoppels.nl>
To: "musl@lists.openwall.com" <musl@lists.openwall.com>
Subject: [musl] [PATCH] Improve locating ld-musl-[arch].path file
Date: Mon, 03 Jan 2022 17:00:19 +0000 [thread overview]
Message-ID: <KORRcazC3jZihuTlLVKOeASexiV0a6ddk52DXfkFH0ZY5cloL3_9jUOPmUMb9dKq4Vy04kiR8qERpRT3Kf1-xdYyiTHg2qHrV1fhHWAosYU=@harmenstoppels.nl> (raw)
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musl locates the config file with search paths relative to the
interpreter/loader by taking the path up to the second to last /, that
is, it tries to drop the filename and dir. This logic is flawed when the
interpreter contains multiple /'s between dir and filename. This commit
fixes that.
Example:
```
$ ./configure "--prefix=$PWD/build" "--syslibdir=$PWD/build/loader/lib"
$ make install -j
$ mkdir -p build/loader/etc example
$ echo "$PWD/example" > "./build/loader/etc/ld-musl-$(arch).path"
$ echo 'int f() {return 0;}' | ./build/bin/musl-gcc -shared -x c - -Wl,-soname,libf.so -o example/libf.so
$ echo 'int f(); int main(){return f();}' | ./build/bin/musl-gcc -x c - -Lexample -lf -o example/a.out
$ ./example/a.out && echo "works"
works
$ patchelf --set-interpreter "$PWD/build/loader/lib//ld-musl-$(arch).so.1" example/a.out
$ ./example/a.out || echo "does not work"
Error loading shared library libf.so: No such file or directory (needed by ./example/a.out)
Error relocating ./example/a.out: f: symbol not found
does not work
```
---
ldso/dynlink.c | 8 ++++++--
1 file changed, 6 insertions(+), 2 deletions(-)
diff --git a/ldso/dynlink.c b/ldso/dynlink.c
index 5b9c8be4..3e7766ac 100644
--- a/ldso/dynlink.c
+++ b/ldso/dynlink.c
@@ -1065,8 +1065,12 @@ static struct dso *load_library(const char *name, struct dso *needed_by)
size_t prefix_len;
if (ldso.name[0]=='/') {
char *s, *t, *z;
- for (s=t=z=ldso.name; *s; s++)
- if (*s=='/') z=t, t=s;
+ s=t=z=ldso.name;
+ do {
+ if (*s++ != '/') continue;
+ z=t, t=s-1;
+ while (*s == '/') ++s;
+ } while (*s);
prefix_len = z-ldso.name;
if (prefix_len < PATH_MAX)
prefix = ldso.name;
--
2.25.1
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reply other threads:[~2022-01-03 17:00 UTC|newest]
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