public inbox for libc-alpha@sourceware.org
 help / color / mirror / Atom feed
* [PATCH v3 0/3] Properly handle DT_RUNPATH
@ 2021-12-08 15:24 H.J. Lu
  2021-12-08 15:24 ` [PATCH v3 1/3] Add and use link-test-modules-rpath-link [BZ #28455] H.J. Lu
                   ` (2 more replies)
  0 siblings, 3 replies; 8+ messages in thread
From: H.J. Lu @ 2021-12-08 15:24 UTC (permalink / raw)
  To: libc-alpha

DT_RUNPATH is only used to find the immediate dependencies of the
executable or shared object containing the DT_RUNPATH entry:

1. Define link-test-modules-rpath-link if $(build-hardcoded-path-in-tests)
is yes.
2. Use $(link-test-modules-rpath-link) in build-module-helper so that
test modules can dlopen modules with DT_RUNPATH.
3. Add a test to show why link-test-modules-rpath-link is needed.
4. The glibc internal NSS functions should always load NSS modules from
the system.  For testing purpose, disable DT_RUNPATH on NSS tests so
that the glibc internal NSS functions can load testing NSS modules
via DT_RPATH.
5. Update glibc LD_AUDIT dlopen call to try the DT_RUNPATH entry of the
executable.

H.J. Lu (3):
  Add and use link-test-modules-rpath-link [BZ #28455]
  Disable DT_RUNPATH on NSS tests [BZ #28455]
  elf: Also try DT_RUNPATH for LD_AUDIT dlopen [BZ #28455]

 Makeconfig           |  2 ++
 Makerules            |  1 +
 elf/Makefile         | 16 ++++++++++++++--
 elf/dl-load.c        | 15 +++++++++++++++
 elf/tst-audit14a.c   |  1 +
 elf/tst-global2.c    | 32 ++++++++++++++++++++++++++++++++
 elf/tst-globalmod2.c | 41 +++++++++++++++++++++++++++++++++++++++++
 nss/Makefile         |  8 ++++++++
 8 files changed, 114 insertions(+), 2 deletions(-)
 create mode 100644 elf/tst-audit14a.c
 create mode 100644 elf/tst-global2.c
 create mode 100644 elf/tst-globalmod2.c

-- 
2.33.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH v3 1/3] Add and use link-test-modules-rpath-link [BZ #28455]
  2021-12-08 15:24 [PATCH v3 0/3] Properly handle DT_RUNPATH H.J. Lu
@ 2021-12-08 15:24 ` H.J. Lu
  2021-12-13 15:32   ` Carlos O'Donell
  2021-12-08 15:25 ` [PATCH v3 2/3] Disable DT_RUNPATH on NSS tests " H.J. Lu
  2021-12-08 15:25 ` [PATCH v3 3/3] elf: Also try DT_RUNPATH for LD_AUDIT dlopen " H.J. Lu
  2 siblings, 1 reply; 8+ messages in thread
From: H.J. Lu @ 2021-12-08 15:24 UTC (permalink / raw)
  To: libc-alpha

DT_RUNPATH is only used to find the immediate dependencies of the
executable or shared object containing the DT_RUNPATH entry:

1. Define link-test-modules-rpath-link if $(build-hardcoded-path-in-tests)
is yes.
2. Use $(link-test-modules-rpath-link) in build-module-helper so that
test modules can dlopen modules with DT_RUNPATH.
3. Add a test to show why link-test-modules-rpath-link is needed.

This partially fixes BZ #28455.
---
 Makeconfig           |  2 ++
 Makerules            |  1 +
 elf/Makefile         |  7 +++++++
 elf/tst-global2.c    | 32 ++++++++++++++++++++++++++++++++
 elf/tst-globalmod2.c | 41 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 83 insertions(+)
 create mode 100644 elf/tst-global2.c
 create mode 100644 elf/tst-globalmod2.c

diff --git a/Makeconfig b/Makeconfig
index 3fa2f13003..2e2b6dbdf9 100644
--- a/Makeconfig
+++ b/Makeconfig
@@ -569,8 +569,10 @@ link-libc-rpath-link = -Wl,-rpath-link=$(rpath-link)
 # build-hardcoded-path-in-tests.
 ifeq (yes,$(build-hardcoded-path-in-tests))
 link-libc-tests-rpath-link = $(link-libc-rpath)
+link-test-modules-rpath-link = $(link-libc-rpath)
 else
 link-libc-tests-rpath-link = $(link-libc-rpath-link)
+link-test-modules-rpath-link =
 endif  # build-hardcoded-path-in-tests
 
 link-libc-between-gnulib = $(common-objpfx)libc.so$(libc.so-version) \
diff --git a/Makerules b/Makerules
index 8db0ca1296..7afba30039 100644
--- a/Makerules
+++ b/Makerules
@@ -591,6 +591,7 @@ $(LINK.o) -shared -static-libgcc $(sysdep-LDFLAGS) $(rtld-LDFLAGS) \
 	  $(if $($(@F)-no-z-defs)$(no-z-defs),,-Wl,-z,defs) \
 	  -B$(csu-objpfx) $(load-map-file) \
 	  $(LDFLAGS.so) $(LDFLAGS-$(@F:%.so=%).so) \
+	  $(link-test-modules-rpath-link) \
 	  -L$(subst :, -L,$(rpath-link)) -Wl,-rpath-link=$(rpath-link)
 endef
 
diff --git a/elf/Makefile b/elf/Makefile
index ef36008673..4b5bdcb08e 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -232,6 +232,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
 	 tst-dl-is_dso tst-ro-dynamic \
 	 tst-audit18 \
 	 tst-rtld-run-static \
+	 tst-global2 \
 #	 reldep9
 tests-internal += loadtest unload unload2 circleload1 \
 	 neededtest neededtest2 neededtest3 neededtest4 \
@@ -374,6 +375,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
 		tst-dlmopen-gethostbyname-mod tst-ro-dynamic-mod \
 		tst-auditmod18 \
 		tst-audit18mod \
+		tst-globalmod2 \
 
 # Most modules build with _ISOMAC defined, but those filtered out
 # depend on internal headers.
@@ -1310,6 +1312,11 @@ tst-audit8-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so
 
 $(objpfx)tst-global1.out: $(objpfx)testobj6.so $(objpfx)testobj2.so
 
+$(objpfx)tst-global2: $(objpfx)tst-globalmod2.so
+$(objpfx)tst-global2.out: $(objpfx)reldepmod1.so $(objpfx)reldepmod4.so
+LDFLAGS-tst-global2 = -Wl,--enable-new-dtags
+LDFLAGS-tst-globalmod2.so = -Wl,--enable-new-dtags
+
 $(objpfx)order2.out: $(objpfx)order2mod1.so $(objpfx)order2mod2.so
 $(objpfx)order2-cmp.out: $(objpfx)order2.out
 	(echo "12345" | cmp $< -) > $@; \
diff --git a/elf/tst-global2.c b/elf/tst-global2.c
new file mode 100644
index 0000000000..e929f526f4
--- /dev/null
+++ b/elf/tst-global2.c
@@ -0,0 +1,32 @@
+/* Test BZ #28455.
+   Copyright (C) 2021 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/>.  */
+
+/* In glibc configured with --enable-hardcoded-path-in-tests, a test
+   program built with -Wl,--enable-new-dtags, which adds DT_RUNPATH,
+   instead of DT_RPATH, can call a function in a shared library, which
+   dlopens another shared library.  */
+
+extern int test (void);
+
+static int
+do_test (void)
+{
+  return test ();
+}
+
+#include <support/test-driver.c>
diff --git a/elf/tst-globalmod2.c b/elf/tst-globalmod2.c
new file mode 100644
index 0000000000..6fd70a72a8
--- /dev/null
+++ b/elf/tst-globalmod2.c
@@ -0,0 +1,41 @@
+/* Test BZ #28455.
+   Copyright (C) 2021 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/>.  */
+
+/* In glibc configured with --enable-hardcoded-path-in-tests, a test
+   program built with -Wl,--enable-new-dtags, which adds DT_RUNPATH,
+   instead of DT_RPATH, can call a function in a shared library, which
+   dlopens another shared library.  */
+
+#include <dlfcn.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+extern int test (void);
+
+int
+test (void)
+{
+  (void) dlopen ("reldepmod4.so", RTLD_LAZY | RTLD_GLOBAL);
+  if (dlsym (RTLD_DEFAULT, "call_me") != NULL)
+    {
+      puts ("found \"call_me\"");
+      return EXIT_SUCCESS;
+    }
+  puts ("didn't find \"call_me\"");
+  return EXIT_FAILURE;
+}
-- 
2.33.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH v3 2/3] Disable DT_RUNPATH on NSS tests [BZ #28455]
  2021-12-08 15:24 [PATCH v3 0/3] Properly handle DT_RUNPATH H.J. Lu
  2021-12-08 15:24 ` [PATCH v3 1/3] Add and use link-test-modules-rpath-link [BZ #28455] H.J. Lu
@ 2021-12-08 15:25 ` H.J. Lu
  2021-12-13 15:29   ` Carlos O'Donell
  2021-12-08 15:25 ` [PATCH v3 3/3] elf: Also try DT_RUNPATH for LD_AUDIT dlopen " H.J. Lu
  2 siblings, 1 reply; 8+ messages in thread
From: H.J. Lu @ 2021-12-08 15:25 UTC (permalink / raw)
  To: libc-alpha

The glibc internal NSS functions should always load NSS modules from
the system.  For testing purpose, disable DT_RUNPATH on NSS tests so
that the glibc internal NSS functions can load testing NSS modules
via DT_RPATH.

This partially fixes BZ #28455.
---
 nss/Makefile | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/nss/Makefile b/nss/Makefile
index bccf9f2806..757446f80a 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -189,3 +189,11 @@ endif
 
 $(objpfx)tst-nss-files-alias-leak.out: $(objpfx)/libnss_files.so
 $(objpfx)tst-nss-files-alias-truncated.out: $(objpfx)/libnss_files.so
+
+# Disable DT_RUNPATH on NSS tests so that the glibc internal NSS
+# functions can load testing NSS modules via DT_RPATH.
+LDFLAGS-tst-nss-test1 = -Wl,--disable-new-dtags
+LDFLAGS-tst-nss-test2 = -Wl,--disable-new-dtags
+LDFLAGS-tst-nss-test3 = -Wl,--disable-new-dtags
+LDFLAGS-tst-nss-test4 = -Wl,--disable-new-dtags
+LDFLAGS-tst-nss-test5 = -Wl,--disable-new-dtags
-- 
2.33.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

* [PATCH v3 3/3] elf: Also try DT_RUNPATH for LD_AUDIT dlopen [BZ #28455]
  2021-12-08 15:24 [PATCH v3 0/3] Properly handle DT_RUNPATH H.J. Lu
  2021-12-08 15:24 ` [PATCH v3 1/3] Add and use link-test-modules-rpath-link [BZ #28455] H.J. Lu
  2021-12-08 15:25 ` [PATCH v3 2/3] Disable DT_RUNPATH on NSS tests " H.J. Lu
@ 2021-12-08 15:25 ` H.J. Lu
  2021-12-13 22:07   ` Carlos O'Donell
  2 siblings, 1 reply; 8+ messages in thread
From: H.J. Lu @ 2021-12-08 15:25 UTC (permalink / raw)
  To: libc-alpha

DT_RUNPATH is only used to find the immediate dependencies of the
executable or shared object containing the DT_RUNPATH entry.  Update
the glibc LD_AUDIT dlopen call to try the DT_RUNPATH entry of the
executable.  This partially fixes BZ #28455.
---
 elf/Makefile       |  9 +++++++--
 elf/dl-load.c      | 15 +++++++++++++++
 elf/tst-audit14a.c |  1 +
 3 files changed, 23 insertions(+), 2 deletions(-)
 create mode 100644 elf/tst-audit14a.c

diff --git a/elf/Makefile b/elf/Makefile
index 4b5bdcb08e..aa6b24d790 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -247,10 +247,10 @@ ifneq ($(selinux-enabled),1)
 tests-execstack-yes = tst-execstack tst-execstack-needed tst-execstack-prog
 endif
 ifeq ($(have-depaudit),yes)
-tests += tst-audit14 tst-audit15 tst-audit16
+tests += tst-audit14 tst-audit15 tst-audit16 tst-audit14a
 ifeq ($(run-built-tests),yes)
 tests-special += $(objpfx)tst-audit14-cmp.out $(objpfx)tst-audit15-cmp.out \
-		 $(objpfx)tst-audit16-cmp.out
+		 $(objpfx)tst-audit16-cmp.out $(objpfx)tst-audit14a-cmp.out
 endif
 endif
 endif
@@ -1521,6 +1521,8 @@ tst-auditmany-ENV = \
 LDFLAGS-tst-audit14 = -Wl,--audit=tst-auditlogmod-1.so
 $(objpfx)tst-auditlogmod-1.so: $(libsupport)
 $(objpfx)tst-audit14.out: $(objpfx)tst-auditlogmod-1.so
+LDFLAGS-tst-audit14a = -Wl,--audit=tst-auditlogmod-1.so,--enable-new-dtags
+$(objpfx)tst-audit14a.out: $(objpfx)tst-auditlogmod-1.so
 LDFLAGS-tst-audit15 = \
   -Wl,--audit=tst-auditlogmod-1.so,--depaudit=tst-auditlogmod-2.so
 $(objpfx)tst-auditlogmod-2.so: $(libsupport)
@@ -1547,6 +1549,9 @@ tst-audit17-ENV = LD_AUDIT=$(objpfx)tst-auditmod17.so
 $(objpfx)tst-audit14-cmp.out: tst-audit14.exp $(objpfx)tst-audit14.out
 	cmp $^ > $@; \
 	$(evaluate-test)
+$(objpfx)tst-audit14a-cmp.out: tst-audit14.exp $(objpfx)tst-audit14a.out
+	cmp $^ > $@; \
+	$(evaluate-test)
 $(objpfx)tst-audit15-cmp.out: tst-audit15.exp $(objpfx)tst-audit15.out
 	cmp $^ > $@; \
 	$(evaluate-test)
diff --git a/elf/dl-load.c b/elf/dl-load.c
index bf8957e73c..1f424ea7c8 100644
--- a/elf/dl-load.c
+++ b/elf/dl-load.c
@@ -2175,6 +2175,21 @@ _dl_map_object (struct link_map *loader, const char *name,
 			    &main_map->l_rpath_dirs,
 			    &realname, &fb, loader ?: main_map, LA_SER_RUNPATH,
 			    &found_other_class);
+
+	  /* Also try DT_RUNPATH in the executable for glibc internal
+	     dlopen call.  */
+	  if (__glibc_unlikely (mode & __RTLD_AUDIT)
+	      && fd == -1 && !did_main_map
+	      && main_map != NULL && main_map->l_type != lt_loaded)
+	    {
+	      struct r_search_path_struct l_rpath_dirs;
+	      l_rpath_dirs.dirs = NULL;
+	      if (cache_rpath (main_map, &l_rpath_dirs,
+			       DT_RUNPATH, "RUNPATH"))
+		fd = open_path (name, namelen, mode, &l_rpath_dirs,
+				&realname, &fb, loader ?: main_map,
+				LA_SER_RUNPATH, &found_other_class);
+	    }
 	}
 
       /* Try the LD_LIBRARY_PATH environment variable.  */
diff --git a/elf/tst-audit14a.c b/elf/tst-audit14a.c
new file mode 100644
index 0000000000..c6232eacf2
--- /dev/null
+++ b/elf/tst-audit14a.c
@@ -0,0 +1 @@
+#include "tst-audit14.c"
-- 
2.33.1


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v3 2/3] Disable DT_RUNPATH on NSS tests [BZ #28455]
  2021-12-08 15:25 ` [PATCH v3 2/3] Disable DT_RUNPATH on NSS tests " H.J. Lu
@ 2021-12-13 15:29   ` Carlos O'Donell
  0 siblings, 0 replies; 8+ messages in thread
From: Carlos O'Donell @ 2021-12-13 15:29 UTC (permalink / raw)
  To: H.J. Lu, libc-alpha

On 12/8/21 10:25, H.J. Lu wrote:
> The glibc internal NSS functions should always load NSS modules from
> the system.  For testing purpose, disable DT_RUNPATH on NSS tests so
> that the glibc internal NSS functions can load testing NSS modules
> via DT_RPATH.

I agree that we should have a consistent tests that are not impacted by the specific
choices of the system toolchain. Using --disable-new-dtags is sufficient to make
this consistent. If we need *more* tests then we can add them.

This change should go in regardless of my comments in 3/3.

LGTM.

Reviewed-by: Carlos O'Donell <carlos@redhat.com>

> This partially fixes BZ #28455.
> ---
>  nss/Makefile | 8 ++++++++
>  1 file changed, 8 insertions(+)
> 
> diff --git a/nss/Makefile b/nss/Makefile
> index bccf9f2806..757446f80a 100644
> --- a/nss/Makefile
> +++ b/nss/Makefile
> @@ -189,3 +189,11 @@ endif
>  
>  $(objpfx)tst-nss-files-alias-leak.out: $(objpfx)/libnss_files.so
>  $(objpfx)tst-nss-files-alias-truncated.out: $(objpfx)/libnss_files.so
> +
> +# Disable DT_RUNPATH on NSS tests so that the glibc internal NSS
> +# functions can load testing NSS modules via DT_RPATH.
> +LDFLAGS-tst-nss-test1 = -Wl,--disable-new-dtags
> +LDFLAGS-tst-nss-test2 = -Wl,--disable-new-dtags
> +LDFLAGS-tst-nss-test3 = -Wl,--disable-new-dtags
> +LDFLAGS-tst-nss-test4 = -Wl,--disable-new-dtags
> +LDFLAGS-tst-nss-test5 = -Wl,--disable-new-dtags

OK. I agree that this is one solution, and that it will work.

> 


-- 
Cheers,
Carlos.


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v3 1/3] Add and use link-test-modules-rpath-link [BZ #28455]
  2021-12-08 15:24 ` [PATCH v3 1/3] Add and use link-test-modules-rpath-link [BZ #28455] H.J. Lu
@ 2021-12-13 15:32   ` Carlos O'Donell
  0 siblings, 0 replies; 8+ messages in thread
From: Carlos O'Donell @ 2021-12-13 15:32 UTC (permalink / raw)
  To: H.J. Lu, libc-alpha

On 12/8/21 10:24, H.J. Lu wrote:
> DT_RUNPATH is only used to find the immediate dependencies of the
> executable or shared object containing the DT_RUNPATH entry:
> 
> 1. Define link-test-modules-rpath-link if $(build-hardcoded-path-in-tests)
> is yes.
> 2. Use $(link-test-modules-rpath-link) in build-module-helper so that
> test modules can dlopen modules with DT_RUNPATH.
> 3. Add a test to show why link-test-modules-rpath-link is needed.

I think should go in regardless of my suggestions in 3/3.

Please post a v4 that is distinct from your series and I'll ACK that.

> This partially fixes BZ #28455.
> ---
>  Makeconfig           |  2 ++
>  Makerules            |  1 +
>  elf/Makefile         |  7 +++++++
>  elf/tst-global2.c    | 32 ++++++++++++++++++++++++++++++++
>  elf/tst-globalmod2.c | 41 +++++++++++++++++++++++++++++++++++++++++
>  5 files changed, 83 insertions(+)
>  create mode 100644 elf/tst-global2.c
>  create mode 100644 elf/tst-globalmod2.c
> 
> diff --git a/Makeconfig b/Makeconfig
> index 3fa2f13003..2e2b6dbdf9 100644
> --- a/Makeconfig
> +++ b/Makeconfig
> @@ -569,8 +569,10 @@ link-libc-rpath-link = -Wl,-rpath-link=$(rpath-link)
>  # build-hardcoded-path-in-tests.
>  ifeq (yes,$(build-hardcoded-path-in-tests))
>  link-libc-tests-rpath-link = $(link-libc-rpath)
> +link-test-modules-rpath-link = $(link-libc-rpath)

OK. Use $(link-libc-rpath) if we are using $(build-hardcoded-path-in-tests)
because with DT_RUNPATH we may need to find the paths with DT_RUNPATH.

>  else
>  link-libc-tests-rpath-link = $(link-libc-rpath-link)
> +link-test-modules-rpath-link =

OK. Otherwise nothing.

>  endif  # build-hardcoded-path-in-tests
>  
>  link-libc-between-gnulib = $(common-objpfx)libc.so$(libc.so-version) \
> diff --git a/Makerules b/Makerules
> index 8db0ca1296..7afba30039 100644
> --- a/Makerules
> +++ b/Makerules
> @@ -591,6 +591,7 @@ $(LINK.o) -shared -static-libgcc $(sysdep-LDFLAGS) $(rtld-LDFLAGS) \
>  	  $(if $($(@F)-no-z-defs)$(no-z-defs),,-Wl,-z,defs) \
>  	  -B$(csu-objpfx) $(load-map-file) \
>  	  $(LDFLAGS.so) $(LDFLAGS-$(@F:%.so=%).so) \
> +	  $(link-test-modules-rpath-link) \

OK.

>  	  -L$(subst :, -L,$(rpath-link)) -Wl,-rpath-link=$(rpath-link)
>  endef
>  
> diff --git a/elf/Makefile b/elf/Makefile
> index ef36008673..4b5bdcb08e 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -232,6 +232,7 @@ tests += restest1 preloadtest loadfail multiload origtest resolvfail \
>  	 tst-dl-is_dso tst-ro-dynamic \
>  	 tst-audit18 \
>  	 tst-rtld-run-static \
> +	 tst-global2 \

Please split and sort to reduce conflicts.

>  #	 reldep9
>  tests-internal += loadtest unload unload2 circleload1 \
>  	 neededtest neededtest2 neededtest3 neededtest4 \
> @@ -374,6 +375,7 @@ modules-names = testobj1 testobj2 testobj3 testobj4 testobj5 testobj6 \
>  		tst-dlmopen-gethostbyname-mod tst-ro-dynamic-mod \
>  		tst-auditmod18 \
>  		tst-audit18mod \
> +		tst-globalmod2 \

Likewise.

>  
>  # Most modules build with _ISOMAC defined, but those filtered out
>  # depend on internal headers.
> @@ -1310,6 +1312,11 @@ tst-audit8-ENV = LD_AUDIT=$(objpfx)tst-auditmod1.so
>  
>  $(objpfx)tst-global1.out: $(objpfx)testobj6.so $(objpfx)testobj2.so
>  
> +$(objpfx)tst-global2: $(objpfx)tst-globalmod2.so

OK. Dep is present for build.

> +$(objpfx)tst-global2.out: $(objpfx)reldepmod1.so $(objpfx)reldepmod4.so

OK. Dep on reldepmod4.so is present for correct buildordering.

> +LDFLAGS-tst-global2 = -Wl,--enable-new-dtags
> +LDFLAGS-tst-globalmod2.so = -Wl,--enable-new-dtags

OK. Force DT_RUNPATH.

> +
>  $(objpfx)order2.out: $(objpfx)order2mod1.so $(objpfx)order2mod2.so
>  $(objpfx)order2-cmp.out: $(objpfx)order2.out
>  	(echo "12345" | cmp $< -) > $@; \
> diff --git a/elf/tst-global2.c b/elf/tst-global2.c
> new file mode 100644
> index 0000000000..e929f526f4
> --- /dev/null
> +++ b/elf/tst-global2.c
> @@ -0,0 +1,32 @@
> +/* Test BZ #28455.

OK.

> +   Copyright (C) 2021 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/>.  */
> +
> +/* In glibc configured with --enable-hardcoded-path-in-tests, a test
> +   program built with -Wl,--enable-new-dtags, which adds DT_RUNPATH,
> +   instead of DT_RPATH, can call a function in a shared library, which
> +   dlopens another shared library.  */
> +
> +extern int test (void);
> +
> +static int
> +do_test (void)
> +{
> +  return test ();
> +}
> +
> +#include <support/test-driver.c>
> diff --git a/elf/tst-globalmod2.c b/elf/tst-globalmod2.c
> new file mode 100644
> index 0000000000..6fd70a72a8
> --- /dev/null
> +++ b/elf/tst-globalmod2.c
> @@ -0,0 +1,41 @@
> +/* Test BZ #28455.
> +   Copyright (C) 2021 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/>.  */
> +
> +/* In glibc configured with --enable-hardcoded-path-in-tests, a test
> +   program built with -Wl,--enable-new-dtags, which adds DT_RUNPATH,
> +   instead of DT_RPATH, can call a function in a shared library, which
> +   dlopens another shared library.  */
> +
> +#include <dlfcn.h>
> +#include <stdio.h>
> +#include <stdlib.h>
> +
> +extern int test (void);
> +
> +int
> +test (void)
> +{
> +  (void) dlopen ("reldepmod4.so", RTLD_LAZY | RTLD_GLOBAL);

OK. Will test that we can find the DSOs from build directory.

> +  if (dlsym (RTLD_DEFAULT, "call_me") != NULL)
> +    {
> +      puts ("found \"call_me\"");
> +      return EXIT_SUCCESS;
> +    }
> +  puts ("didn't find \"call_me\"");
> +  return EXIT_FAILURE;
> +}
> 


-- 
Cheers,
Carlos.


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v3 3/3] elf: Also try DT_RUNPATH for LD_AUDIT dlopen [BZ #28455]
  2021-12-08 15:25 ` [PATCH v3 3/3] elf: Also try DT_RUNPATH for LD_AUDIT dlopen " H.J. Lu
@ 2021-12-13 22:07   ` Carlos O'Donell
  2021-12-16  2:07     ` H.J. Lu
  0 siblings, 1 reply; 8+ messages in thread
From: Carlos O'Donell @ 2021-12-13 22:07 UTC (permalink / raw)
  To: H.J. Lu, libc-alpha

On 12/8/21 10:25, H.J. Lu wrote:
> DT_RUNPATH is only used to find the immediate dependencies of the
> executable or shared object containing the DT_RUNPATH entry.  Update
> the glibc LD_AUDIT dlopen call to try the DT_RUNPATH entry of the
> executable.  This partially fixes BZ #28455.

Please post v4 split out.

> ---
>  elf/Makefile       |  9 +++++++--
>  elf/dl-load.c      | 15 +++++++++++++++
>  elf/tst-audit14a.c |  1 +
>  3 files changed, 23 insertions(+), 2 deletions(-)
>  create mode 100644 elf/tst-audit14a.c
> 
> diff --git a/elf/Makefile b/elf/Makefile
> index 4b5bdcb08e..aa6b24d790 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -247,10 +247,10 @@ ifneq ($(selinux-enabled),1)
>  tests-execstack-yes = tst-execstack tst-execstack-needed tst-execstack-prog
>  endif
>  ifeq ($(have-depaudit),yes)
> -tests += tst-audit14 tst-audit15 tst-audit16
> +tests += tst-audit14 tst-audit15 tst-audit16 tst-audit14a

Please split one test per line and sort.

>  ifeq ($(run-built-tests),yes)
>  tests-special += $(objpfx)tst-audit14-cmp.out $(objpfx)tst-audit15-cmp.out \
> -		 $(objpfx)tst-audit16-cmp.out
> +		 $(objpfx)tst-audit16-cmp.out $(objpfx)tst-audit14a-cmp.out

Please split one test per line and sort.

>  endif
>  endif
>  endif
> @@ -1521,6 +1521,8 @@ tst-auditmany-ENV = \
>  LDFLAGS-tst-audit14 = -Wl,--audit=tst-auditlogmod-1.so
>  $(objpfx)tst-auditlogmod-1.so: $(libsupport)
>  $(objpfx)tst-audit14.out: $(objpfx)tst-auditlogmod-1.so
> +LDFLAGS-tst-audit14a = -Wl,--audit=tst-auditlogmod-1.so,--enable-new-dtags
> +$(objpfx)tst-audit14a.out: $(objpfx)tst-auditlogmod-1.so

OK.

>  LDFLAGS-tst-audit15 = \
>    -Wl,--audit=tst-auditlogmod-1.so,--depaudit=tst-auditlogmod-2.so
>  $(objpfx)tst-auditlogmod-2.so: $(libsupport)
> @@ -1547,6 +1549,9 @@ tst-audit17-ENV = LD_AUDIT=$(objpfx)tst-auditmod17.so
>  $(objpfx)tst-audit14-cmp.out: tst-audit14.exp $(objpfx)tst-audit14.out
>  	cmp $^ > $@; \
>  	$(evaluate-test)
> +$(objpfx)tst-audit14a-cmp.out: tst-audit14.exp $(objpfx)tst-audit14a.out
> +	cmp $^ > $@; \
> +	$(evaluate-test)

OK.

>  $(objpfx)tst-audit15-cmp.out: tst-audit15.exp $(objpfx)tst-audit15.out
>  	cmp $^ > $@; \
>  	$(evaluate-test)
> diff --git a/elf/dl-load.c b/elf/dl-load.c
> index bf8957e73c..1f424ea7c8 100644
> --- a/elf/dl-load.c
> +++ b/elf/dl-load.c

The preceding block is like this:

2146       /* When the object has the RUNPATH information we don't use any
2147          RPATHs.  */
2148       if (loader == NULL || loader->l_info[DT_RUNPATH] == NULL)
2149         {

The entire design of this block is to look into DT_RPATH specifically
under two conditions:

(a) We don't know anything about the loading module, it is NULL, and
    therefore we don't know if DT_RUNPATH was present, which if it
    was present, would prevent the use of DT_RPATH.

(b) We have a loader, and we know it doesn't have DT_RUNPATH and so
    we will look for DT_RPATH.

Your changes adds (c) to this case in which DT_RUNPATH is used, and
this seems to be logically distinct from the above two cases.

My suggestion is that the code you are adding should be in a distinct
block *after* the above block starting around line 2189.

We already have a block like this:
2189       /* Look at the RUNPATH information for this binary.  */
2190       if (fd == -1 && loader != NULL
2191           && cache_rpath (loader, &loader->l_runpath_dirs,
2192                           DT_RUNPATH, "RUNPATH"))
2193         fd = open_path (name, namelen, mode,
2194                         &loader->l_runpath_dirs, &realname, &fb, loader,
2195                         LA_SER_RUNPATH, &found_other_class);

I think it is logically more correct to add to this DT_RUNPATH handling
than ato add to the DT_RPATH handling above.

So after this block you might add:

/* When processing the lookup we may need to additionally try DT_RUNPATH
   in the executable for a glibc internal dlopen call when looking for
   audit modules.  */
if (__glibc_unlikely (mode & __RTLD_AUDIT)
    && fd == -1)
  {
    ...
  }

The hard part is that you may want to know a few things:
(a) main_map (unavailable, but computable via GL(dl_ns)[LM_ID_BASE]._ns_loaded)
(b) did_main_map (unavailable)
    * This seems like an optimization because if you already looked up via
      main_map and it failed, doing it twice won't help, so you can refactor
      did_main_map to function scope and retain the fact that you did this
      check already if you want to keep the optimization.

Otherwise everything else is there to implement the fix.

> @@ -2175,6 +2175,21 @@ _dl_map_object (struct link_map *loader, const char *name,
>  			    &main_map->l_rpath_dirs,
>  			    &realname, &fb, loader ?: main_map, LA_SER_RUNPATH,
>  			    &found_other_class);
> +
> +	  /* Also try DT_RUNPATH in the executable for glibc internal
> +	     dlopen call.  */
> +	  if (__glibc_unlikely (mode & __RTLD_AUDIT)
> +	      && fd == -1 && !did_main_map
> +	      && main_map != NULL && main_map->l_type != lt_loaded)
> +	    {
> +	      struct r_search_path_struct l_rpath_dirs;
> +	      l_rpath_dirs.dirs = NULL;
> +	      if (cache_rpath (main_map, &l_rpath_dirs,
> +			       DT_RUNPATH, "RUNPATH"))
> +		fd = open_path (name, namelen, mode, &l_rpath_dirs,
> +				&realname, &fb, loader ?: main_map,
> +				LA_SER_RUNPATH, &found_other_class);
> +	    }
>  	}
>  
>        /* Try the LD_LIBRARY_PATH environment variable.  */
> diff --git a/elf/tst-audit14a.c b/elf/tst-audit14a.c
> new file mode 100644
> index 0000000000..c6232eacf2
> --- /dev/null
> +++ b/elf/tst-audit14a.c
> @@ -0,0 +1 @@
> +#include "tst-audit14.c"
> 


-- 
Cheers,
Carlos.


^ permalink raw reply	[flat|nested] 8+ messages in thread

* Re: [PATCH v3 3/3] elf: Also try DT_RUNPATH for LD_AUDIT dlopen [BZ #28455]
  2021-12-13 22:07   ` Carlos O'Donell
@ 2021-12-16  2:07     ` H.J. Lu
  0 siblings, 0 replies; 8+ messages in thread
From: H.J. Lu @ 2021-12-16  2:07 UTC (permalink / raw)
  To: Carlos O'Donell; +Cc: GNU C Library

On Mon, Dec 13, 2021 at 2:07 PM Carlos O'Donell <carlos@redhat.com> wrote:
>
> On 12/8/21 10:25, H.J. Lu wrote:
> > DT_RUNPATH is only used to find the immediate dependencies of the
> > executable or shared object containing the DT_RUNPATH entry.  Update
> > the glibc LD_AUDIT dlopen call to try the DT_RUNPATH entry of the
> > executable.  This partially fixes BZ #28455.
>
> Please post v4 split out.
>
> > ---
> >  elf/Makefile       |  9 +++++++--
> >  elf/dl-load.c      | 15 +++++++++++++++
> >  elf/tst-audit14a.c |  1 +
> >  3 files changed, 23 insertions(+), 2 deletions(-)
> >  create mode 100644 elf/tst-audit14a.c
> >
> > diff --git a/elf/Makefile b/elf/Makefile
> > index 4b5bdcb08e..aa6b24d790 100644
> > --- a/elf/Makefile
> > +++ b/elf/Makefile
> > @@ -247,10 +247,10 @@ ifneq ($(selinux-enabled),1)
> >  tests-execstack-yes = tst-execstack tst-execstack-needed tst-execstack-prog
> >  endif
> >  ifeq ($(have-depaudit),yes)
> > -tests += tst-audit14 tst-audit15 tst-audit16
> > +tests += tst-audit14 tst-audit15 tst-audit16 tst-audit14a
>
> Please split one test per line and sort.

Fixed.

> >  ifeq ($(run-built-tests),yes)
> >  tests-special += $(objpfx)tst-audit14-cmp.out $(objpfx)tst-audit15-cmp.out \
> > -              $(objpfx)tst-audit16-cmp.out
> > +              $(objpfx)tst-audit16-cmp.out $(objpfx)tst-audit14a-cmp.out
>
> Please split one test per line and sort.

Fixed.

> >  endif
> >  endif
> >  endif
> > @@ -1521,6 +1521,8 @@ tst-auditmany-ENV = \
> >  LDFLAGS-tst-audit14 = -Wl,--audit=tst-auditlogmod-1.so
> >  $(objpfx)tst-auditlogmod-1.so: $(libsupport)
> >  $(objpfx)tst-audit14.out: $(objpfx)tst-auditlogmod-1.so
> > +LDFLAGS-tst-audit14a = -Wl,--audit=tst-auditlogmod-1.so,--enable-new-dtags
> > +$(objpfx)tst-audit14a.out: $(objpfx)tst-auditlogmod-1.so
>
> OK.
>
> >  LDFLAGS-tst-audit15 = \
> >    -Wl,--audit=tst-auditlogmod-1.so,--depaudit=tst-auditlogmod-2.so
> >  $(objpfx)tst-auditlogmod-2.so: $(libsupport)
> > @@ -1547,6 +1549,9 @@ tst-audit17-ENV = LD_AUDIT=$(objpfx)tst-auditmod17.so
> >  $(objpfx)tst-audit14-cmp.out: tst-audit14.exp $(objpfx)tst-audit14.out
> >       cmp $^ > $@; \
> >       $(evaluate-test)
> > +$(objpfx)tst-audit14a-cmp.out: tst-audit14.exp $(objpfx)tst-audit14a.out
> > +     cmp $^ > $@; \
> > +     $(evaluate-test)
>
> OK.
>
> >  $(objpfx)tst-audit15-cmp.out: tst-audit15.exp $(objpfx)tst-audit15.out
> >       cmp $^ > $@; \
> >       $(evaluate-test)
> > diff --git a/elf/dl-load.c b/elf/dl-load.c
> > index bf8957e73c..1f424ea7c8 100644
> > --- a/elf/dl-load.c
> > +++ b/elf/dl-load.c
>
> The preceding block is like this:
>
> 2146       /* When the object has the RUNPATH information we don't use any
> 2147          RPATHs.  */
> 2148       if (loader == NULL || loader->l_info[DT_RUNPATH] == NULL)
> 2149         {
>
> The entire design of this block is to look into DT_RPATH specifically
> under two conditions:
>
> (a) We don't know anything about the loading module, it is NULL, and
>     therefore we don't know if DT_RUNPATH was present, which if it
>     was present, would prevent the use of DT_RPATH.
>
> (b) We have a loader, and we know it doesn't have DT_RUNPATH and so
>     we will look for DT_RPATH.
>
> Your changes adds (c) to this case in which DT_RUNPATH is used, and
> this seems to be logically distinct from the above two cases.
>
> My suggestion is that the code you are adding should be in a distinct
> block *after* the above block starting around line 2189.
>
> We already have a block like this:
> 2189       /* Look at the RUNPATH information for this binary.  */
> 2190       if (fd == -1 && loader != NULL
> 2191           && cache_rpath (loader, &loader->l_runpath_dirs,
> 2192                           DT_RUNPATH, "RUNPATH"))
> 2193         fd = open_path (name, namelen, mode,
> 2194                         &loader->l_runpath_dirs, &realname, &fb, loader,
> 2195                         LA_SER_RUNPATH, &found_other_class);
>
> I think it is logically more correct to add to this DT_RUNPATH handling
> than ato add to the DT_RPATH handling above.
>
> So after this block you might add:
>
> /* When processing the lookup we may need to additionally try DT_RUNPATH
>    in the executable for a glibc internal dlopen call when looking for
>    audit modules.  */
> if (__glibc_unlikely (mode & __RTLD_AUDIT)
>     && fd == -1)
>   {
>     ...
>   }

Fixed.

> The hard part is that you may want to know a few things:
> (a) main_map (unavailable, but computable via GL(dl_ns)[LM_ID_BASE]._ns_loaded)
> (b) did_main_map (unavailable)
>     * This seems like an optimization because if you already looked up via
>       main_map and it failed, doing it twice won't help, so you can refactor
>       did_main_map to function scope and retain the fact that you did this
>       check already if you want to keep the optimization.

Fixed.

> Otherwise everything else is there to implement the fix.
>

Sent out the v4 patch.

Thanks.

-- 
H.J.

^ permalink raw reply	[flat|nested] 8+ messages in thread

end of thread, other threads:[~2021-12-16  2:07 UTC | newest]

Thread overview: 8+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-12-08 15:24 [PATCH v3 0/3] Properly handle DT_RUNPATH H.J. Lu
2021-12-08 15:24 ` [PATCH v3 1/3] Add and use link-test-modules-rpath-link [BZ #28455] H.J. Lu
2021-12-13 15:32   ` Carlos O'Donell
2021-12-08 15:25 ` [PATCH v3 2/3] Disable DT_RUNPATH on NSS tests " H.J. Lu
2021-12-13 15:29   ` Carlos O'Donell
2021-12-08 15:25 ` [PATCH v3 3/3] elf: Also try DT_RUNPATH for LD_AUDIT dlopen " H.J. Lu
2021-12-13 22:07   ` Carlos O'Donell
2021-12-16  2:07     ` H.J. Lu

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for read-only IMAP folder(s) and NNTP newsgroup(s).