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| author | Geoffrey Thomas <geofft@ldpreload.com> | 2025-02-18 15:58:16 -0500 |
|---|---|---|
| committer | Adhemerval Zanella <adhemerval.zanella@linaro.org> | 2025-03-03 17:05:21 -0300 |
| commit | 372c632ce7c78471dbda69ca33625d1ecb6fb2f7 (patch) | |
| tree | 77a0d5c2ae9aeca4d195e170771234bffe473cbf /elf/Makefile | |
| parent | 9e51ae3cd0c7f65bdeba93b7f1d780cdb21fc269 (diff) | |
| download | glibc-azanella/bz25263-loader-realpath.tar.xz glibc-azanella/bz25263-loader-realpath.zip | |
elf: Canonicalize $ORIGIN in an explicit ld.so invocation [BZ 25263]azanella/bz25263-loader-realpath
When an executable is invoked directly, we calculate $ORIGIN by calling
readlink on /proc/self/exe, which the Linux kernel resolves to the
target of any symlinks. However, if an executable is run through ld.so,
we cannot use /proc/self/exe and instead use the path given as an
argument. This leads to a different calculation of $ORIGIN, which is
most notable in that it causes ldd to behave differently (e.g., by not
finding a library) from directly running the program.
To make the behavior consistent, take advantage of the fact that the
kernel also resolves /proc/self/fd/ symlinks to the target of any
symlinks in the same manner, so once we have opened the main executable
in order to load it, replace the user-provided path with the result of
calling readlink("/proc/self/fd/N").
(On non-Linux platforms this resolution does not happen and so no
behavior change is needed.)
Co-authored-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>
Diffstat (limited to 'elf/Makefile')
| -rw-r--r-- | elf/Makefile | 23 |
1 files changed, 23 insertions, 0 deletions
diff --git a/elf/Makefile b/elf/Makefile index 1ea0e7037e..3267f28a62 100644 --- a/elf/Makefile +++ b/elf/Makefile @@ -455,6 +455,7 @@ tests += \ tst-noload \ tst-non-directory-path \ tst-null-argv \ + tst-origin \ tst-p_align1 \ tst-p_align2 \ tst-p_align3 \ @@ -761,6 +762,7 @@ modules-names += \ libmarkermod5-3 \ libmarkermod5-4 \ libmarkermod5-5 \ + liborigin-mod \ libtracemod1-1 \ libtracemod2-1 \ libtracemod3-1 \ @@ -3397,3 +3399,24 @@ $(objpfx)tst-nolink-libc-2: $(objpfx)tst-nolink-libc.o -Wl,--dynamic-linker=$(objpfx)ld.so $(objpfx)tst-nolink-libc-2.out: $(objpfx)tst-nolink-libc-2 $(objpfx)ld.so $< > $@ 2>&1; $(evaluate-test) + + +$(objpfx)tst-origin: $(objpfx)tst-origin.o $(objpfx)liborigin-mod.so + $(LINK.o) -o $@ -B$(csu-objpfx) $(LDFLAGS.so) $< \ + -Wl,-rpath,\$$ORIGIN \ + -L$(subst :, -L,$(rpath-link)) -Wl,--no-as-needed -lorigin-mod +$(objpfx)liborigin-mod.so: $(objpfx)liborigin-mod.os + $(LINK.o) -shared -o $@ -B$(csu-objpfx) $(LDFLAGS.so) \ + $(LDFLAGS-soname-fname) \ + $< +$(objpfx)tst-origin.out: tst-origin.sh $(objpfx)tst-origin + $(SHELL) \ + $< \ + '$(common-objpfx)' \ + '$(test-wrapper-env)' \ + '$(run-program-env)' \ + '$(rpath-link)' \ + tst-origin \ + liborigin-mod.so \ + > $@; \ + $(evaluate-test) |