mirror of
git://sourceware.org/git/glibc.git
synced 2025-03-31 14:01:18 +08:00
elf: Canonicalize $ORIGIN in an explicit ld.so invocation [BZ 25263]
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>
This commit is contained in:
parent
9e51ae3cd0
commit
372c632ce7
23
elf/Makefile
23
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)
|
||||
|
@ -965,6 +965,12 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd,
|
||||
{
|
||||
assert (nsid == LM_ID_BASE);
|
||||
memset (&id, 0, sizeof (id));
|
||||
char *realname_can = _dl_canonicalize (fd);
|
||||
if (realname_can != NULL)
|
||||
{
|
||||
free (realname);
|
||||
realname = realname_can;
|
||||
}
|
||||
}
|
||||
else
|
||||
{
|
||||
|
@ -47,3 +47,9 @@ _dl_get_origin (void)
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
char *
|
||||
_dl_canonicalize (int fd)
|
||||
{
|
||||
return NULL;
|
||||
}
|
||||
|
1
elf/liborigin-mod.c
Normal file
1
elf/liborigin-mod.c
Normal file
@ -0,0 +1 @@
|
||||
void foo (void) {}
|
26
elf/tst-origin.c
Normal file
26
elf/tst-origin.c
Normal file
@ -0,0 +1,26 @@
|
||||
/* Test if $ORIGIN works correctly with symlinks (BZ#25263)
|
||||
Copyright (C) 2025 Free Software Foundation, Inc.
|
||||
This file is part of the GNU C Library.
|
||||
|
||||
The GNU C Library is free software; you can redistribute it and/or
|
||||
modify it under the terms of the GNU Lesser General Public
|
||||
License as published by the Free Software Foundation; either
|
||||
version 2.1 of the License, or (at your option) any later version.
|
||||
|
||||
The GNU C Library is distributed in the hope that it will be useful,
|
||||
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
Lesser General Public License for more details.
|
||||
|
||||
You should have received a copy of the GNU Lesser General Public
|
||||
License along with the GNU C Library; if not, see
|
||||
<https://www.gnu.org/licenses/>. */
|
||||
|
||||
extern void foo (void);
|
||||
|
||||
int
|
||||
main (int argc, char *argv[])
|
||||
{
|
||||
foo ();
|
||||
return 0;
|
||||
}
|
60
elf/tst-origin.sh
Executable file
60
elf/tst-origin.sh
Executable file
@ -0,0 +1,60 @@
|
||||
#!/bin/sh
|
||||
# Test if $ORIGIN works correctly with symlinks (BZ 25263)
|
||||
# Copyright (C) 2025 Free Software Foundation, Inc.
|
||||
# This file is part of the GNU C Library.
|
||||
|
||||
# The GNU C Library is free software; you can redistribute it and/or
|
||||
# modify it under the terms of the GNU Lesser General Public
|
||||
# License as published by the Free Software Foundation; either
|
||||
# version 2.1 of the License, or (at your option) any later version.
|
||||
|
||||
# The GNU C Library is distributed in the hope that it will be useful,
|
||||
# but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
# Lesser General Public License for more details.
|
||||
|
||||
# You should have received a copy of the GNU Lesser General Public
|
||||
# License along with the GNU C Library; if not, see
|
||||
# <https://www.gnu.org/licenses/>.
|
||||
|
||||
set -e
|
||||
|
||||
objpfx=$1
|
||||
test_wrapper_env=$2
|
||||
run_program_env=$3
|
||||
library_path=$4
|
||||
test_program=$5
|
||||
test_library=$6
|
||||
|
||||
cleanup()
|
||||
{
|
||||
# Move the binary and library back to build directory
|
||||
mv $tmpdir/sub/$test_program ${objpfx}elf
|
||||
mv $tmpdir/sub/$test_library ${objpfx}elf
|
||||
|
||||
rm -rf $tmpdir
|
||||
}
|
||||
|
||||
tmpdir=$(mktemp -d "${objpfx}elf/tst-origin.XXXXXXXXXX")
|
||||
#trap cleanup 0
|
||||
|
||||
mkdir ${tmpdir}/sub
|
||||
|
||||
# Remove the dependency from $library_path
|
||||
mv ${objpfx}elf/$test_program $tmpdir/sub
|
||||
mv ${objpfx}elf/$test_library $tmpdir/sub
|
||||
|
||||
cd ${tmpdir}
|
||||
ln -s sub/$test_program $test_program
|
||||
|
||||
#${test_wrapper_env} \
|
||||
#${run_program_env} \
|
||||
#${objpfx}elf/ld.so --library-path "$library_path" \
|
||||
# ./$test_program 2>&1 && rc=0 || rc=$?
|
||||
|
||||
# Also check if ldd resolves the dependency
|
||||
LD_TRACE_LOADED_OBJECTS=1 \
|
||||
${objpfx}elf/ld.so --library-path "$library_path" \
|
||||
./$test_program 2>&1 | grep 'not found' && rc=1 || rc=0
|
||||
|
||||
exit $rc
|
@ -1223,6 +1223,10 @@ extern struct link_map * _dl_get_dl_main_map (void) attribute_hidden;
|
||||
/* Find origin of the executable. */
|
||||
extern const char *_dl_get_origin (void) attribute_hidden;
|
||||
|
||||
/* Return the canonalized path name from the opened file descriptor FD,
|
||||
or NULL otherwise. */
|
||||
extern char * _dl_canonicalize (int fd) attribute_hidden;
|
||||
|
||||
/* Count DSTs. */
|
||||
extern size_t _dl_dst_count (const char *name) attribute_hidden;
|
||||
|
||||
|
@ -300,6 +300,8 @@ ifeq ($(subdir),elf)
|
||||
check-execstack-xfail += ld.so libc.so libpthread.so
|
||||
# We always create a thread for signals
|
||||
test-xfail-tst-single_threaded-pthread-static = yes
|
||||
# Bug 25263
|
||||
test-xfail-tst-origin = yes
|
||||
|
||||
CFLAGS-tst-execstack.c += -DDEFAULT_RWX_STACK=1
|
||||
endif
|
||||
|
@ -21,6 +21,7 @@
|
||||
#include <fcntl.h>
|
||||
#include <ldsodefs.h>
|
||||
#include <sysdep.h>
|
||||
#include <fd_to_filename.h>
|
||||
|
||||
/* On Linux >= 2.1 systems which have the dcache implementation we can get
|
||||
the path of the application from the /proc/self/exe symlink. Try this
|
||||
@ -72,3 +73,23 @@ _dl_get_origin (void)
|
||||
|
||||
return result;
|
||||
}
|
||||
|
||||
/* On Linux, readlink on the magic symlinks in /proc/self/fd also has
|
||||
the same behavior of returning the canonical path from the dcache.
|
||||
If it does not work, we do not bother to canonicalize. */
|
||||
|
||||
char *
|
||||
_dl_canonicalize (int fd)
|
||||
{
|
||||
struct fd_to_filename fdfilename;
|
||||
char canonical[PATH_MAX];
|
||||
char *path = __fd_to_filename (fd, &fdfilename);
|
||||
int size = INTERNAL_SYSCALL_CALL (readlinkat, AT_FDCWD, path,
|
||||
canonical, PATH_MAX - 1);
|
||||
if (size >= 0)
|
||||
{
|
||||
canonical[size] = '\0';
|
||||
return __strdup (canonical);
|
||||
}
|
||||
return NULL;
|
||||
}
|
||||
|
Loading…
x
Reference in New Issue
Block a user