* [PATCH v3 1/2] nss: Do not mention NSS test modules in <gnu/lib-names.h>
@ 2022-03-10 16:17 Florian Weimer
2022-03-10 16:18 ` [PATCH v3 2/2] nss: Protect against errno changes in function lookup (bug 28953) Florian Weimer
2022-03-10 22:22 ` [PATCH v3 1/2] nss: Do not mention NSS test modules in <gnu/lib-names.h> Carlos O'Donell
0 siblings, 2 replies; 5+ messages in thread
From: Florian Weimer @ 2022-03-10 16:17 UTC (permalink / raw)
To: libc-alpha
They are not actually installed. Use the nss_files version instead
in nss/Makefile, similar to how __nss_shlib_revision is derived
from LIBNSS_FILES_SO.
---
v3: Unchanged from v2.
nss/Makefile | 13 +++++--------
shlib-versions | 5 -----
2 files changed, 5 insertions(+), 13 deletions(-)
diff --git a/nss/Makefile b/nss/Makefile
index 552e5d03e1..74e2c2426c 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -171,17 +171,14 @@ $(objpfx)/libnss_test1.so: $(objpfx)nss_test1.os $(link-libc-deps)
$(objpfx)/libnss_test2.so: $(objpfx)nss_test2.os $(link-libc-deps)
$(build-module)
$(objpfx)nss_test2.os : nss_test1.c
-ifdef libnss_test1.so-version
-$(objpfx)/libnss_test1.so$(libnss_test1.so-version): $(objpfx)/libnss_test1.so
+# Use the nss_files suffix for these objects as well.
+$(objpfx)/libnss_test1.so$(libnss_files.so-version): $(objpfx)/libnss_test1.so
$(make-link)
-endif
-ifdef libnss_test2.so-version
-$(objpfx)/libnss_test2.so$(libnss_test2.so-version): $(objpfx)/libnss_test2.so
+$(objpfx)/libnss_test2.so$(libnss_files.so-version): $(objpfx)/libnss_test2.so
$(make-link)
-endif
$(patsubst %,$(objpfx)%.out,$(tests) $(tests-container)) : \
- $(objpfx)/libnss_test1.so$(libnss_test1.so-version) \
- $(objpfx)/libnss_test2.so$(libnss_test2.so-version)
+ $(objpfx)/libnss_test1.so$(libnss_files.so-version) \
+ $(objpfx)/libnss_test2.so$(libnss_files.so-version)
ifeq (yes,$(have-thread-library))
$(objpfx)tst-cancel-getpwuid_r: $(shared-thread-library)
diff --git a/shlib-versions b/shlib-versions
index df6603e699..b87ab50c59 100644
--- a/shlib-versions
+++ b/shlib-versions
@@ -47,11 +47,6 @@ libnss_ldap=2
libnss_hesiod=2
libnss_db=2
-# Tests for NSS. They must have the same NSS_SHLIB_REVISION number as
-# the rest.
-libnss_test1=2
-libnss_test2=2
-
# Version for libnsl with YP and NIS+ functions.
libnsl=1
base-commit: d653fd2d9ebe23c2b16b76edf717c5dbd5ce9b77
--
2.35.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* [PATCH v3 2/2] nss: Protect against errno changes in function lookup (bug 28953)
2022-03-10 16:17 [PATCH v3 1/2] nss: Do not mention NSS test modules in <gnu/lib-names.h> Florian Weimer
@ 2022-03-10 16:18 ` Florian Weimer
2022-03-10 16:37 ` Cristian Rodríguez
2022-03-10 22:28 ` Carlos O'Donell
2022-03-10 22:22 ` [PATCH v3 1/2] nss: Do not mention NSS test modules in <gnu/lib-names.h> Carlos O'Donell
1 sibling, 2 replies; 5+ messages in thread
From: Florian Weimer @ 2022-03-10 16:18 UTC (permalink / raw)
To: libc-alpha
dlopen may clobber errno. The nss_test_errno module uses an ELF
constructor to achieve that, but there could be internal errors
during dlopen that cause this, too. Therefore, the NSS framework
has to guard against such errno clobbers.
__nss_module_get_function is currently the only function that calls
__nss_module_load, so it is sufficient to save and restore errno
around this call.
---
v3: Do not change errno on module load failure due to existing ambiguity.
nss/Makefile | 15 ++++++++--
nss/nss_module.c | 12 +++++++-
nss/nss_test_errno.c | 58 ++++++++++++++++++++++++++++++++++++++
nss/tst-nss-test_errno.c | 61 ++++++++++++++++++++++++++++++++++++++++
4 files changed, 142 insertions(+), 4 deletions(-)
create mode 100644 nss/nss_test_errno.c
create mode 100644 nss/tst-nss-test_errno.c
diff --git a/nss/Makefile b/nss/Makefile
index 74e2c2426c..de439d4911 100644
--- a/nss/Makefile
+++ b/nss/Makefile
@@ -60,7 +60,8 @@ tests = test-netdb test-digits-dots tst-nss-getpwent bug17079 \
tst-nss-test1 \
tst-nss-test2 \
tst-nss-test4 \
- tst-nss-test5
+ tst-nss-test5 \
+ tst-nss-test_errno
xtests = bug-erange
tests-container = \
@@ -132,7 +133,7 @@ libnss_compat-inhibit-o = $(filter-out .os,$(object-suffixes))
ifeq ($(build-static-nss),yes)
tests-static += tst-nss-static
endif
-extra-test-objs += nss_test1.os nss_test2.os
+extra-test-objs += nss_test1.os nss_test2.os nss_test_errno.os
include ../Rules
@@ -166,19 +167,26 @@ rtld-tests-LDFLAGS += -Wl,--dynamic-list=nss_test.ver
libof-nss_test1 = extramodules
libof-nss_test2 = extramodules
+libof-nss_test_errno = extramodules
$(objpfx)/libnss_test1.so: $(objpfx)nss_test1.os $(link-libc-deps)
$(build-module)
$(objpfx)/libnss_test2.so: $(objpfx)nss_test2.os $(link-libc-deps)
$(build-module)
+$(objpfx)/libnss_test_errno.so: $(objpfx)nss_test_errno.os $(link-libc-deps)
+ $(build-module)
$(objpfx)nss_test2.os : nss_test1.c
# Use the nss_files suffix for these objects as well.
$(objpfx)/libnss_test1.so$(libnss_files.so-version): $(objpfx)/libnss_test1.so
$(make-link)
$(objpfx)/libnss_test2.so$(libnss_files.so-version): $(objpfx)/libnss_test2.so
$(make-link)
+$(objpfx)/libnss_test_errno.so$(libnss_files.so-version): \
+ $(objpfx)/libnss_test_errno.so
+ $(make-link)
$(patsubst %,$(objpfx)%.out,$(tests) $(tests-container)) : \
$(objpfx)/libnss_test1.so$(libnss_files.so-version) \
- $(objpfx)/libnss_test2.so$(libnss_files.so-version)
+ $(objpfx)/libnss_test2.so$(libnss_files.so-version) \
+ $(objpfx)/libnss_test_errno.so$(libnss_files.so-version)
ifeq (yes,$(have-thread-library))
$(objpfx)tst-cancel-getpwuid_r: $(shared-thread-library)
@@ -194,3 +202,4 @@ 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
+LDFLAGS-tst-nss-test_errno = -Wl,--disable-new-dtags
diff --git a/nss/nss_module.c b/nss/nss_module.c
index f9a1263e5a..f00bbd9e1a 100644
--- a/nss/nss_module.c
+++ b/nss/nss_module.c
@@ -330,8 +330,18 @@ name_search (const void *left, const void *right)
void *
__nss_module_get_function (struct nss_module *module, const char *name)
{
+ /* A successful dlopen might clobber errno. */
+ int saved_errno = errno;
+
if (!__nss_module_load (module))
- return NULL;
+ {
+ /* Reporting module load failure is currently inaccurate. See
+ bug 22041. Not changing errno is the conservative choice. */
+ __set_errno (saved_errno);
+ return NULL;
+ }
+
+ __set_errno (saved_errno);
function_name *name_entry = bsearch (name, nss_function_name_array,
array_length (nss_function_name_array),
diff --git a/nss/nss_test_errno.c b/nss/nss_test_errno.c
new file mode 100644
index 0000000000..680f8a07b9
--- /dev/null
+++ b/nss/nss_test_errno.c
@@ -0,0 +1,58 @@
+/* NSS service provider with errno clobber.
+ Copyright (C) 2022 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/>. */
+
+#include <errno.h>
+#include <nss.h>
+#include <stdlib.h>
+
+/* Catch misnamed and functions. */
+#pragma GCC diagnostic error "-Wmissing-prototypes"
+NSS_DECLARE_MODULE_FUNCTIONS (test_errno)
+
+static void __attribute__ ((constructor))
+init (void)
+{
+ /* An arbitrary error code which is otherwise not used. */
+ errno = ELIBBAD;
+}
+
+/* Lookup functions for pwd follow that do not return any data. */
+
+/* Catch misnamed function definitions. */
+
+enum nss_status
+_nss_test_errno_setpwent (int stayopen)
+{
+ setenv ("_nss_test_errno_setpwent", "yes", 1);
+ return NSS_STATUS_SUCCESS;
+}
+
+enum nss_status
+_nss_test_errno_getpwent_r (struct passwd *result,
+ char *buffer, size_t size, int *errnop)
+{
+ setenv ("_nss_test_errno_getpwent_r", "yes", 1);
+ return NSS_STATUS_NOTFOUND;
+}
+
+enum nss_status
+_nss_test_errno_endpwent (void)
+{
+ setenv ("_nss_test_errno_endpwent", "yes", 1);
+ return NSS_STATUS_SUCCESS;
+}
diff --git a/nss/tst-nss-test_errno.c b/nss/tst-nss-test_errno.c
new file mode 100644
index 0000000000..d2c42dd363
--- /dev/null
+++ b/nss/tst-nss-test_errno.c
@@ -0,0 +1,61 @@
+/* getpwent failure when dlopen clobbers errno (bug 28953).
+ Copyright (C) 2022 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/>. */
+
+#include <nss.h>
+#include <support/check.h>
+#include <stdlib.h>
+#include <errno.h>
+#include <stdbool.h>
+#include <pwd.h>
+#include <string.h>
+
+static int
+do_test (void)
+{
+ __nss_configure_lookup ("passwd", "files test_errno");
+
+ errno = 0;
+ setpwent ();
+ TEST_COMPARE (errno, 0);
+
+ bool root_seen = false;
+ while (true)
+ {
+ errno = 0;
+ struct passwd *e = getpwent ();
+ if (e == NULL)
+ break;
+ if (strcmp (e->pw_name, "root"))
+ root_seen = true;
+ }
+
+ TEST_COMPARE (errno, 0);
+ TEST_VERIFY (root_seen);
+
+ errno = 0;
+ endpwent ();
+ TEST_COMPARE (errno, 0);
+
+ TEST_COMPARE_STRING (getenv ("_nss_test_errno_setpwent"), "yes");
+ TEST_COMPARE_STRING (getenv ("_nss_test_errno_getpwent_r"), "yes");
+ TEST_COMPARE_STRING (getenv ("_nss_test_errno_endpwent"), "yes");
+
+ return 0;
+}
+
+#include <support/test-driver.c>
--
2.35.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 2/2] nss: Protect against errno changes in function lookup (bug 28953)
2022-03-10 16:18 ` [PATCH v3 2/2] nss: Protect against errno changes in function lookup (bug 28953) Florian Weimer
@ 2022-03-10 16:37 ` Cristian Rodríguez
2022-03-10 22:28 ` Carlos O'Donell
1 sibling, 0 replies; 5+ messages in thread
From: Cristian Rodríguez @ 2022-03-10 16:37 UTC (permalink / raw)
To: Florian Weimer; +Cc: libc-alpha
On Thu, Mar 10, 2022 at 1:19 PM Florian Weimer via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> dlopen may clobber errno. The nss_test_errno module uses an ELF
> constructor to achieve that, but there could be internal errors
> during dlopen that cause this, too. Therefore, the NSS framework
> has to guard against such errno clobbers.
elf constructors may also clobber errno.. I know the standard does not
require errno to be sane on entering main() but it would be awesome if
that was always the case..or that the real constraints and pitfalls of
them are documented on the gcc manual page, that is currently very
vague about it..
Other than saving and restoring errno..what else ? do they have to be
as-safe right ? this is not mentioned anywhere...or Im blind,
>
> __nss_module_get_function is currently the only function that calls
> __nss_module_load, so it is sufficient to save and restore errno
> around this call.
> ---
> v3: Do not change errno on module load failure due to existing ambiguity.
>
> nss/Makefile | 15 ++++++++--
> nss/nss_module.c | 12 +++++++-
> nss/nss_test_errno.c | 58 ++++++++++++++++++++++++++++++++++++++
> nss/tst-nss-test_errno.c | 61 ++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 142 insertions(+), 4 deletions(-)
> create mode 100644 nss/nss_test_errno.c
> create mode 100644 nss/tst-nss-test_errno.c
>
> diff --git a/nss/Makefile b/nss/Makefile
> index 74e2c2426c..de439d4911 100644
> --- a/nss/Makefile
> +++ b/nss/Makefile
> @@ -60,7 +60,8 @@ tests = test-netdb test-digits-dots tst-nss-getpwent bug17079 \
> tst-nss-test1 \
> tst-nss-test2 \
> tst-nss-test4 \
> - tst-nss-test5
> + tst-nss-test5 \
> + tst-nss-test_errno
> xtests = bug-erange
>
> tests-container = \
> @@ -132,7 +133,7 @@ libnss_compat-inhibit-o = $(filter-out .os,$(object-suffixes))
> ifeq ($(build-static-nss),yes)
> tests-static += tst-nss-static
> endif
> -extra-test-objs += nss_test1.os nss_test2.os
> +extra-test-objs += nss_test1.os nss_test2.os nss_test_errno.os
>
> include ../Rules
>
> @@ -166,19 +167,26 @@ rtld-tests-LDFLAGS += -Wl,--dynamic-list=nss_test.ver
>
> libof-nss_test1 = extramodules
> libof-nss_test2 = extramodules
> +libof-nss_test_errno = extramodules
> $(objpfx)/libnss_test1.so: $(objpfx)nss_test1.os $(link-libc-deps)
> $(build-module)
> $(objpfx)/libnss_test2.so: $(objpfx)nss_test2.os $(link-libc-deps)
> $(build-module)
> +$(objpfx)/libnss_test_errno.so: $(objpfx)nss_test_errno.os $(link-libc-deps)
> + $(build-module)
> $(objpfx)nss_test2.os : nss_test1.c
> # Use the nss_files suffix for these objects as well.
> $(objpfx)/libnss_test1.so$(libnss_files.so-version): $(objpfx)/libnss_test1.so
> $(make-link)
> $(objpfx)/libnss_test2.so$(libnss_files.so-version): $(objpfx)/libnss_test2.so
> $(make-link)
> +$(objpfx)/libnss_test_errno.so$(libnss_files.so-version): \
> + $(objpfx)/libnss_test_errno.so
> + $(make-link)
> $(patsubst %,$(objpfx)%.out,$(tests) $(tests-container)) : \
> $(objpfx)/libnss_test1.so$(libnss_files.so-version) \
> - $(objpfx)/libnss_test2.so$(libnss_files.so-version)
> + $(objpfx)/libnss_test2.so$(libnss_files.so-version) \
> + $(objpfx)/libnss_test_errno.so$(libnss_files.so-version)
>
> ifeq (yes,$(have-thread-library))
> $(objpfx)tst-cancel-getpwuid_r: $(shared-thread-library)
> @@ -194,3 +202,4 @@ 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
> +LDFLAGS-tst-nss-test_errno = -Wl,--disable-new-dtags
> diff --git a/nss/nss_module.c b/nss/nss_module.c
> index f9a1263e5a..f00bbd9e1a 100644
> --- a/nss/nss_module.c
> +++ b/nss/nss_module.c
> @@ -330,8 +330,18 @@ name_search (const void *left, const void *right)
> void *
> __nss_module_get_function (struct nss_module *module, const char *name)
> {
> + /* A successful dlopen might clobber errno. */
> + int saved_errno = errno;
> +
> if (!__nss_module_load (module))
> - return NULL;
> + {
> + /* Reporting module load failure is currently inaccurate. See
> + bug 22041. Not changing errno is the conservative choice. */
> + __set_errno (saved_errno);
> + return NULL;
> + }
> +
> + __set_errno (saved_errno);
>
> function_name *name_entry = bsearch (name, nss_function_name_array,
> array_length (nss_function_name_array),
> diff --git a/nss/nss_test_errno.c b/nss/nss_test_errno.c
> new file mode 100644
> index 0000000000..680f8a07b9
> --- /dev/null
> +++ b/nss/nss_test_errno.c
> @@ -0,0 +1,58 @@
> +/* NSS service provider with errno clobber.
> + Copyright (C) 2022 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/>. */
> +
> +#include <errno.h>
> +#include <nss.h>
> +#include <stdlib.h>
> +
> +/* Catch misnamed and functions. */
> +#pragma GCC diagnostic error "-Wmissing-prototypes"
> +NSS_DECLARE_MODULE_FUNCTIONS (test_errno)
> +
> +static void __attribute__ ((constructor))
> +init (void)
> +{
> + /* An arbitrary error code which is otherwise not used. */
> + errno = ELIBBAD;
> +}
> +
> +/* Lookup functions for pwd follow that do not return any data. */
> +
> +/* Catch misnamed function definitions. */
> +
> +enum nss_status
> +_nss_test_errno_setpwent (int stayopen)
> +{
> + setenv ("_nss_test_errno_setpwent", "yes", 1);
> + return NSS_STATUS_SUCCESS;
> +}
> +
> +enum nss_status
> +_nss_test_errno_getpwent_r (struct passwd *result,
> + char *buffer, size_t size, int *errnop)
> +{
> + setenv ("_nss_test_errno_getpwent_r", "yes", 1);
> + return NSS_STATUS_NOTFOUND;
> +}
> +
> +enum nss_status
> +_nss_test_errno_endpwent (void)
> +{
> + setenv ("_nss_test_errno_endpwent", "yes", 1);
> + return NSS_STATUS_SUCCESS;
> +}
> diff --git a/nss/tst-nss-test_errno.c b/nss/tst-nss-test_errno.c
> new file mode 100644
> index 0000000000..d2c42dd363
> --- /dev/null
> +++ b/nss/tst-nss-test_errno.c
> @@ -0,0 +1,61 @@
> +/* getpwent failure when dlopen clobbers errno (bug 28953).
> + Copyright (C) 2022 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/>. */
> +
> +#include <nss.h>
> +#include <support/check.h>
> +#include <stdlib.h>
> +#include <errno.h>
> +#include <stdbool.h>
> +#include <pwd.h>
> +#include <string.h>
> +
> +static int
> +do_test (void)
> +{
> + __nss_configure_lookup ("passwd", "files test_errno");
> +
> + errno = 0;
> + setpwent ();
> + TEST_COMPARE (errno, 0);
> +
> + bool root_seen = false;
> + while (true)
> + {
> + errno = 0;
> + struct passwd *e = getpwent ();
> + if (e == NULL)
> + break;
> + if (strcmp (e->pw_name, "root"))
> + root_seen = true;
> + }
> +
> + TEST_COMPARE (errno, 0);
> + TEST_VERIFY (root_seen);
> +
> + errno = 0;
> + endpwent ();
> + TEST_COMPARE (errno, 0);
> +
> + TEST_COMPARE_STRING (getenv ("_nss_test_errno_setpwent"), "yes");
> + TEST_COMPARE_STRING (getenv ("_nss_test_errno_getpwent_r"), "yes");
> + TEST_COMPARE_STRING (getenv ("_nss_test_errno_endpwent"), "yes");
> +
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
> --
> 2.35.1
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 1/2] nss: Do not mention NSS test modules in <gnu/lib-names.h>
2022-03-10 16:17 [PATCH v3 1/2] nss: Do not mention NSS test modules in <gnu/lib-names.h> Florian Weimer
2022-03-10 16:18 ` [PATCH v3 2/2] nss: Protect against errno changes in function lookup (bug 28953) Florian Weimer
@ 2022-03-10 22:22 ` Carlos O'Donell
1 sibling, 0 replies; 5+ messages in thread
From: Carlos O'Donell @ 2022-03-10 22:22 UTC (permalink / raw)
To: Florian Weimer, libc-alpha
On 3/10/22 11:17, Florian Weimer via Libc-alpha wrote:
> They are not actually installed. Use the nss_files version instead
> in nss/Makefile, similar to how __nss_shlib_revision is derived
> from LIBNSS_FILES_SO.
Agreed. This removes the test files from shlib_versions.
LGTM.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> ---
> v3: Unchanged from v2.
> nss/Makefile | 13 +++++--------
> shlib-versions | 5 -----
> 2 files changed, 5 insertions(+), 13 deletions(-)
>
> diff --git a/nss/Makefile b/nss/Makefile
> index 552e5d03e1..74e2c2426c 100644
> --- a/nss/Makefile
> +++ b/nss/Makefile
> @@ -171,17 +171,14 @@ $(objpfx)/libnss_test1.so: $(objpfx)nss_test1.os $(link-libc-deps)
> $(objpfx)/libnss_test2.so: $(objpfx)nss_test2.os $(link-libc-deps)
> $(build-module)
> $(objpfx)nss_test2.os : nss_test1.c
> -ifdef libnss_test1.so-version
> -$(objpfx)/libnss_test1.so$(libnss_test1.so-version): $(objpfx)/libnss_test1.so
> +# Use the nss_files suffix for these objects as well.
OK.
> +$(objpfx)/libnss_test1.so$(libnss_files.so-version): $(objpfx)/libnss_test1.so
> $(make-link)
> -endif
> -ifdef libnss_test2.so-version
> -$(objpfx)/libnss_test2.so$(libnss_test2.so-version): $(objpfx)/libnss_test2.so
> +$(objpfx)/libnss_test2.so$(libnss_files.so-version): $(objpfx)/libnss_test2.so
> $(make-link)
> -endif
> $(patsubst %,$(objpfx)%.out,$(tests) $(tests-container)) : \
> - $(objpfx)/libnss_test1.so$(libnss_test1.so-version) \
> - $(objpfx)/libnss_test2.so$(libnss_test2.so-version)
> + $(objpfx)/libnss_test1.so$(libnss_files.so-version) \
> + $(objpfx)/libnss_test2.so$(libnss_files.so-version)
OK.
>
> ifeq (yes,$(have-thread-library))
> $(objpfx)tst-cancel-getpwuid_r: $(shared-thread-library)
> diff --git a/shlib-versions b/shlib-versions
> index df6603e699..b87ab50c59 100644
> --- a/shlib-versions
> +++ b/shlib-versions
> @@ -47,11 +47,6 @@ libnss_ldap=2
> libnss_hesiod=2
> libnss_db=2
>
> -# Tests for NSS. They must have the same NSS_SHLIB_REVISION number as
> -# the rest.
> -libnss_test1=2
> -libnss_test2=2
> -
OK.
> # Version for libnsl with YP and NIS+ functions.
> libnsl=1
>
>
> base-commit: d653fd2d9ebe23c2b16b76edf717c5dbd5ce9b77
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [PATCH v3 2/2] nss: Protect against errno changes in function lookup (bug 28953)
2022-03-10 16:18 ` [PATCH v3 2/2] nss: Protect against errno changes in function lookup (bug 28953) Florian Weimer
2022-03-10 16:37 ` Cristian Rodríguez
@ 2022-03-10 22:28 ` Carlos O'Donell
1 sibling, 0 replies; 5+ messages in thread
From: Carlos O'Donell @ 2022-03-10 22:28 UTC (permalink / raw)
To: Florian Weimer, libc-alpha
On 3/10/22 11:18, Florian Weimer via Libc-alpha wrote:
> dlopen may clobber errno. The nss_test_errno module uses an ELF
> constructor to achieve that, but there could be internal errors
> during dlopen that cause this, too. Therefore, the NSS framework
> has to guard against such errno clobbers.
LGTM.
Addresses Andreas' other comments about the the failed return, and the missing
license etc.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
> __nss_module_get_function is currently the only function that calls
> __nss_module_load, so it is sufficient to save and restore errno
> around this call.
Agreed.
> ---
> v3: Do not change errno on module load failure due to existing ambiguity.
>
> nss/Makefile | 15 ++++++++--
> nss/nss_module.c | 12 +++++++-
> nss/nss_test_errno.c | 58 ++++++++++++++++++++++++++++++++++++++
> nss/tst-nss-test_errno.c | 61 ++++++++++++++++++++++++++++++++++++++++
> 4 files changed, 142 insertions(+), 4 deletions(-)
> create mode 100644 nss/nss_test_errno.c
> create mode 100644 nss/tst-nss-test_errno.c
>
> diff --git a/nss/Makefile b/nss/Makefile
> index 74e2c2426c..de439d4911 100644
> --- a/nss/Makefile
> +++ b/nss/Makefile
> @@ -60,7 +60,8 @@ tests = test-netdb test-digits-dots tst-nss-getpwent bug17079 \
> tst-nss-test1 \
> tst-nss-test2 \
> tst-nss-test4 \
> - tst-nss-test5
> + tst-nss-test5 \
> + tst-nss-test_errno
OK.
> xtests = bug-erange
>
> tests-container = \
> @@ -132,7 +133,7 @@ libnss_compat-inhibit-o = $(filter-out .os,$(object-suffixes))
> ifeq ($(build-static-nss),yes)
> tests-static += tst-nss-static
> endif
> -extra-test-objs += nss_test1.os nss_test2.os
> +extra-test-objs += nss_test1.os nss_test2.os nss_test_errno.os
OK.
>
> include ../Rules
>
> @@ -166,19 +167,26 @@ rtld-tests-LDFLAGS += -Wl,--dynamic-list=nss_test.ver
>
> libof-nss_test1 = extramodules
> libof-nss_test2 = extramodules
> +libof-nss_test_errno = extramodules
OK.
> $(objpfx)/libnss_test1.so: $(objpfx)nss_test1.os $(link-libc-deps)
> $(build-module)
> $(objpfx)/libnss_test2.so: $(objpfx)nss_test2.os $(link-libc-deps)
> $(build-module)
> +$(objpfx)/libnss_test_errno.so: $(objpfx)nss_test_errno.os $(link-libc-deps)
> + $(build-module)
OK.
> $(objpfx)nss_test2.os : nss_test1.c
> # Use the nss_files suffix for these objects as well.
> $(objpfx)/libnss_test1.so$(libnss_files.so-version): $(objpfx)/libnss_test1.so
> $(make-link)
> $(objpfx)/libnss_test2.so$(libnss_files.so-version): $(objpfx)/libnss_test2.so
> $(make-link)
> +$(objpfx)/libnss_test_errno.so$(libnss_files.so-version): \
> + $(objpfx)/libnss_test_errno.so
> + $(make-link)
OK.
> $(patsubst %,$(objpfx)%.out,$(tests) $(tests-container)) : \
> $(objpfx)/libnss_test1.so$(libnss_files.so-version) \
> - $(objpfx)/libnss_test2.so$(libnss_files.so-version)
> + $(objpfx)/libnss_test2.so$(libnss_files.so-version) \
> + $(objpfx)/libnss_test_errno.so$(libnss_files.so-version)
OK.
>
> ifeq (yes,$(have-thread-library))
> $(objpfx)tst-cancel-getpwuid_r: $(shared-thread-library)
> @@ -194,3 +202,4 @@ 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
> +LDFLAGS-tst-nss-test_errno = -Wl,--disable-new-dtags
OK.
> diff --git a/nss/nss_module.c b/nss/nss_module.c
> index f9a1263e5a..f00bbd9e1a 100644
> --- a/nss/nss_module.c
> +++ b/nss/nss_module.c
> @@ -330,8 +330,18 @@ name_search (const void *left, const void *right)
> void *
> __nss_module_get_function (struct nss_module *module, const char *name)
> {
> + /* A successful dlopen might clobber errno. */
> + int saved_errno = errno;
OK. Save on entry.
> +
> if (!__nss_module_load (module))
> - return NULL;
> + {
> + /* Reporting module load failure is currently inaccurate. See
> + bug 22041. Not changing errno is the conservative choice. */
> + __set_errno (saved_errno);
> + return NULL;
OK. Agreed.
> + }
> +
> + __set_errno (saved_errno);
OK. Nothing after this would set errno.
>
> function_name *name_entry = bsearch (name, nss_function_name_array,
> array_length (nss_function_name_array),
> diff --git a/nss/nss_test_errno.c b/nss/nss_test_errno.c
> new file mode 100644
> index 0000000000..680f8a07b9
> --- /dev/null
> +++ b/nss/nss_test_errno.c
> @@ -0,0 +1,58 @@
> +/* NSS service provider with errno clobber.
OK.
> + Copyright (C) 2022 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/>. */
> +
> +#include <errno.h>
> +#include <nss.h>
> +#include <stdlib.h>
> +
> +/* Catch misnamed and functions. */
> +#pragma GCC diagnostic error "-Wmissing-prototypes"
OK. Belt-and-suspenders.
> +NSS_DECLARE_MODULE_FUNCTIONS (test_errno)
> +
> +static void __attribute__ ((constructor))
> +init (void)
> +{
> + /* An arbitrary error code which is otherwise not used. */
> + errno = ELIBBAD;
> +}
> +
> +/* Lookup functions for pwd follow that do not return any data. */
> +
> +/* Catch misnamed function definitions. */
> +
> +enum nss_status
> +_nss_test_errno_setpwent (int stayopen)
> +{
> + setenv ("_nss_test_errno_setpwent", "yes", 1);
> + return NSS_STATUS_SUCCESS;
> +}
> +
> +enum nss_status
> +_nss_test_errno_getpwent_r (struct passwd *result,
> + char *buffer, size_t size, int *errnop)
> +{
> + setenv ("_nss_test_errno_getpwent_r", "yes", 1);
> + return NSS_STATUS_NOTFOUND;
> +}
> +
> +enum nss_status
> +_nss_test_errno_endpwent (void)
> +{
> + setenv ("_nss_test_errno_endpwent", "yes", 1);
> + return NSS_STATUS_SUCCESS;
> +}
> diff --git a/nss/tst-nss-test_errno.c b/nss/tst-nss-test_errno.c
> new file mode 100644
> index 0000000000..d2c42dd363
> --- /dev/null
> +++ b/nss/tst-nss-test_errno.c
> @@ -0,0 +1,61 @@
> +/* getpwent failure when dlopen clobbers errno (bug 28953).
OK.
> + Copyright (C) 2022 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/>. */
> +
> +#include <nss.h>
> +#include <support/check.h>
> +#include <stdlib.h>
> +#include <errno.h>
> +#include <stdbool.h>
> +#include <pwd.h>
> +#include <string.h>
> +
> +static int
> +do_test (void)
> +{
> + __nss_configure_lookup ("passwd", "files test_errno");
OK. Use test NSS provider.
> +
> + errno = 0;
> + setpwent ();
OK. Constructor changes things.
> + TEST_COMPARE (errno, 0);
> +
> + bool root_seen = false;
> + while (true)
> + {
> + errno = 0;
> + struct passwd *e = getpwent ();
> + if (e == NULL)
> + break;
> + if (strcmp (e->pw_name, "root"))
> + root_seen = true;
> + }
> +
> + TEST_COMPARE (errno, 0);
OK.
> + TEST_VERIFY (root_seen);
> +
> + errno = 0;
> + endpwent ();
OK.
> + TEST_COMPARE (errno, 0);
> +
> + TEST_COMPARE_STRING (getenv ("_nss_test_errno_setpwent"), "yes");
> + TEST_COMPARE_STRING (getenv ("_nss_test_errno_getpwent_r"), "yes");
> + TEST_COMPARE_STRING (getenv ("_nss_test_errno_endpwent"), "yes");
OK. Slightly unorthodox to use an environment variable, but simple and useful.
> +
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
--
Cheers,
Carlos.
^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-03-10 22:28 UTC | newest]
Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed)
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2022-03-10 16:17 [PATCH v3 1/2] nss: Do not mention NSS test modules in <gnu/lib-names.h> Florian Weimer
2022-03-10 16:18 ` [PATCH v3 2/2] nss: Protect against errno changes in function lookup (bug 28953) Florian Weimer
2022-03-10 16:37 ` Cristian Rodríguez
2022-03-10 22:28 ` Carlos O'Donell
2022-03-10 22:22 ` [PATCH v3 1/2] nss: Do not mention NSS test modules in <gnu/lib-names.h> Carlos O'Donell
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