* [PATCH] elf: Call __libc_early_init for reused namespaces (bug 29528)
@ 2022-08-26 12:45 Florian Weimer
2022-08-26 17:57 ` H.J. Lu
0 siblings, 1 reply; 3+ messages in thread
From: Florian Weimer @ 2022-08-26 12:45 UTC (permalink / raw)
To: libc-alpha
libc_map is never reset to NULL, neither during dlclose nor on a
dlopen call which reuses the namespace structure. As a result, if a
namespace is reused, its libc is not initialized properly. The most
visible result is a crash in the <ctype.h> functions.
To prevent similar bugs on namespace reuse from surfacing,
unconditionally initialize the chosen namespace to zero using memset.
Tested on i686-linux-gnu and x86_64-linux-gnu. Built with
build-many-glibcs.py.
---
elf/Makefile | 7 +++++++
elf/dl-open.c | 13 +++++++-----
elf/tst-dlmopen-twice-mod1.c | 37 ++++++++++++++++++++++++++++++++
elf/tst-dlmopen-twice-mod2.c | 50 ++++++++++++++++++++++++++++++++++++++++++++
elf/tst-dlmopen-twice.c | 34 ++++++++++++++++++++++++++++++
5 files changed, 136 insertions(+), 5 deletions(-)
diff --git a/elf/Makefile b/elf/Makefile
index 3928a08787..008770bfaf 100644
--- a/elf/Makefile
+++ b/elf/Makefile
@@ -410,6 +410,7 @@ tests += \
tst-dlmopen4 \
tst-dlmopen-dlerror \
tst-dlmopen-gethostbyname \
+ tst-dlmopen-twice \
tst-dlopenfail \
tst-dlopenfail-2 \
tst-dlopenrpath \
@@ -839,6 +840,8 @@ modules-names += \
tst-dlmopen1mod \
tst-dlmopen-dlerror-mod \
tst-dlmopen-gethostbyname-mod \
+ tst-dlmopen-twice-mod1 \
+ tst-dlmopen-twice-mod2 \
tst-dlopenfaillinkmod \
tst-dlopenfailmod1 \
tst-dlopenfailmod2 \
@@ -2976,3 +2979,7 @@ $(objpfx)tst-audit-tlsdesc.out: $(objpfx)tst-auditmod-tlsdesc.so
tst-audit-tlsdesc-ENV = LD_AUDIT=$(objpfx)tst-auditmod-tlsdesc.so
$(objpfx)tst-audit-tlsdesc-dlopen.out: $(objpfx)tst-auditmod-tlsdesc.so
tst-audit-tlsdesc-dlopen-ENV = LD_AUDIT=$(objpfx)tst-auditmod-tlsdesc.so
+
+$(objpfx)tst-dlmopen-twice.out: \
+ $(objpfx)tst-dlmopen-twice-mod1.so \
+ $(objpfx)tst-dlmopen-twice-mod2.so
diff --git a/elf/dl-open.c b/elf/dl-open.c
index a23e65926b..46e8066fd8 100644
--- a/elf/dl-open.c
+++ b/elf/dl-open.c
@@ -844,11 +844,14 @@ _dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid,
_dl_signal_error (EINVAL, file, NULL, N_("\
no more namespaces available for dlmopen()"));
}
- else if (nsid == GL(dl_nns))
- {
- __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock);
- ++GL(dl_nns);
- }
+
+ if (nsid == GL(dl_nns))
+ ++GL(dl_nns);
+
+ /* Initialize the new namespace. Most members are
+ zero-initialized, only the lock needs special treatment. */
+ memset (&GL(dl_ns)[nsid], 0, sizeof (GL(dl_ns)[nsid]));
+ __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock);
_dl_debug_update (nsid)->r_state = RT_CONSISTENT;
}
diff --git a/elf/tst-dlmopen-twice-mod1.c b/elf/tst-dlmopen-twice-mod1.c
new file mode 100644
index 0000000000..38a3a5f0ac
--- /dev/null
+++ b/elf/tst-dlmopen-twice-mod1.c
@@ -0,0 +1,37 @@
+/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Module 1.
+ 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 <stdio.h>
+
+static void __attribute__ ((constructor))
+init (void)
+{
+ puts ("info: tst-dlmopen-twice-mod2.so loaded");
+ fflush (stdout);
+}
+
+static void __attribute__ ((destructor))
+fini (void)
+{
+ puts ("info: tst-dlmopen-twice-mod2.so about to be unloaded");
+ fflush (stdout);
+}
+
+/* Large allocation. The second module does not have this, so it
+ should load libc at a different address. */
+char large_allocate[16 * 1024 * 1024];
diff --git a/elf/tst-dlmopen-twice-mod2.c b/elf/tst-dlmopen-twice-mod2.c
new file mode 100644
index 0000000000..40c6c01f96
--- /dev/null
+++ b/elf/tst-dlmopen-twice-mod2.c
@@ -0,0 +1,50 @@
+/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Module 2.
+ 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 <ctype.h>
+#include <stdio.h>
+
+static void __attribute__ ((constructor))
+init (void)
+{
+ puts ("info: tst-dlmopen-twice-mod2.so loaded");
+ fflush (stdout);
+}
+
+static void __attribute__ ((destructor))
+fini (void)
+{
+ puts ("info: tst-dlmopen-twice-mod2.so about to be unloaded");
+ fflush (stdout);
+}
+
+int
+run_check (void)
+{
+ puts ("info: about to call isalpha");
+ fflush (stdout);
+
+ volatile char ch = 'a';
+ if (!isalpha (ch))
+ {
+ puts ("error: isalpha ('a') is not true");
+ fflush (stdout);
+ return 1;
+ }
+ return 0;
+}
diff --git a/elf/tst-dlmopen-twice.c b/elf/tst-dlmopen-twice.c
new file mode 100644
index 0000000000..449f3c8fa9
--- /dev/null
+++ b/elf/tst-dlmopen-twice.c
@@ -0,0 +1,34 @@
+/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Main.
+ 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 <support/xdlfcn.h>
+#include <support/check.h>
+
+static int
+do_test (void)
+{
+ void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod1.so", RTLD_NOW);
+ xdlclose (handle);
+ handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod2.so", RTLD_NOW);
+ int (*run_check) (void) = xdlsym (handle, "run_check");
+ TEST_COMPARE (run_check (), 0);
+ xdlclose (handle);
+ return 0;
+}
+
+#include <support/test-driver.c>
base-commit: 5ecc98241229d494aaad23a4a3fe106fe11e1f40
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] elf: Call __libc_early_init for reused namespaces (bug 29528)
2022-08-26 12:45 [PATCH] elf: Call __libc_early_init for reused namespaces (bug 29528) Florian Weimer
@ 2022-08-26 17:57 ` H.J. Lu
2022-08-26 18:11 ` Florian Weimer
0 siblings, 1 reply; 3+ messages in thread
From: H.J. Lu @ 2022-08-26 17:57 UTC (permalink / raw)
To: Florian Weimer; +Cc: GNU C Library
On Fri, Aug 26, 2022 at 5:46 AM Florian Weimer via Libc-alpha
<libc-alpha@sourceware.org> wrote:
>
> libc_map is never reset to NULL, neither during dlclose nor on a
> dlopen call which reuses the namespace structure. As a result, if a
> namespace is reused, its libc is not initialized properly. The most
> visible result is a crash in the <ctype.h> functions.
>
> To prevent similar bugs on namespace reuse from surfacing,
> unconditionally initialize the chosen namespace to zero using memset.
>
> Tested on i686-linux-gnu and x86_64-linux-gnu. Built with
> build-many-glibcs.py.
>
> ---
> elf/Makefile | 7 +++++++
> elf/dl-open.c | 13 +++++++-----
> elf/tst-dlmopen-twice-mod1.c | 37 ++++++++++++++++++++++++++++++++
> elf/tst-dlmopen-twice-mod2.c | 50 ++++++++++++++++++++++++++++++++++++++++++++
> elf/tst-dlmopen-twice.c | 34 ++++++++++++++++++++++++++++++
> 5 files changed, 136 insertions(+), 5 deletions(-)
>
> diff --git a/elf/Makefile b/elf/Makefile
> index 3928a08787..008770bfaf 100644
> --- a/elf/Makefile
> +++ b/elf/Makefile
> @@ -410,6 +410,7 @@ tests += \
> tst-dlmopen4 \
> tst-dlmopen-dlerror \
> tst-dlmopen-gethostbyname \
> + tst-dlmopen-twice \
> tst-dlopenfail \
> tst-dlopenfail-2 \
> tst-dlopenrpath \
> @@ -839,6 +840,8 @@ modules-names += \
> tst-dlmopen1mod \
> tst-dlmopen-dlerror-mod \
> tst-dlmopen-gethostbyname-mod \
> + tst-dlmopen-twice-mod1 \
> + tst-dlmopen-twice-mod2 \
> tst-dlopenfaillinkmod \
> tst-dlopenfailmod1 \
> tst-dlopenfailmod2 \
> @@ -2976,3 +2979,7 @@ $(objpfx)tst-audit-tlsdesc.out: $(objpfx)tst-auditmod-tlsdesc.so
> tst-audit-tlsdesc-ENV = LD_AUDIT=$(objpfx)tst-auditmod-tlsdesc.so
> $(objpfx)tst-audit-tlsdesc-dlopen.out: $(objpfx)tst-auditmod-tlsdesc.so
> tst-audit-tlsdesc-dlopen-ENV = LD_AUDIT=$(objpfx)tst-auditmod-tlsdesc.so
> +
> +$(objpfx)tst-dlmopen-twice.out: \
> + $(objpfx)tst-dlmopen-twice-mod1.so \
> + $(objpfx)tst-dlmopen-twice-mod2.so
> diff --git a/elf/dl-open.c b/elf/dl-open.c
> index a23e65926b..46e8066fd8 100644
> --- a/elf/dl-open.c
> +++ b/elf/dl-open.c
> @@ -844,11 +844,14 @@ _dl_open (const char *file, int mode, const void *caller_dlopen, Lmid_t nsid,
> _dl_signal_error (EINVAL, file, NULL, N_("\
> no more namespaces available for dlmopen()"));
> }
> - else if (nsid == GL(dl_nns))
> - {
> - __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock);
> - ++GL(dl_nns);
> - }
> +
> + if (nsid == GL(dl_nns))
> + ++GL(dl_nns);
> +
> + /* Initialize the new namespace. Most members are
> + zero-initialized, only the lock needs special treatment. */
> + memset (&GL(dl_ns)[nsid], 0, sizeof (GL(dl_ns)[nsid]));
> + __rtld_lock_initialize (GL(dl_ns)[nsid]._ns_unique_sym_table.lock);
>
> _dl_debug_update (nsid)->r_state = RT_CONSISTENT;
> }
> diff --git a/elf/tst-dlmopen-twice-mod1.c b/elf/tst-dlmopen-twice-mod1.c
> new file mode 100644
> index 0000000000..38a3a5f0ac
> --- /dev/null
> +++ b/elf/tst-dlmopen-twice-mod1.c
> @@ -0,0 +1,37 @@
> +/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Module 1.
> + 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 <stdio.h>
> +
> +static void __attribute__ ((constructor))
> +init (void)
> +{
> + puts ("info: tst-dlmopen-twice-mod2.so loaded");
Did you mean tst-dlmopen-twice-mod1.so?
> + fflush (stdout);
> +}
> +
> +static void __attribute__ ((destructor))
> +fini (void)
> +{
> + puts ("info: tst-dlmopen-twice-mod2.so about to be unloaded");
Likewise.
> + fflush (stdout);
> +}
> +
> +/* Large allocation. The second module does not have this, so it
> + should load libc at a different address. */
> +char large_allocate[16 * 1024 * 1024];
> diff --git a/elf/tst-dlmopen-twice-mod2.c b/elf/tst-dlmopen-twice-mod2.c
> new file mode 100644
> index 0000000000..40c6c01f96
> --- /dev/null
> +++ b/elf/tst-dlmopen-twice-mod2.c
> @@ -0,0 +1,50 @@
> +/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Module 2.
> + 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 <ctype.h>
> +#include <stdio.h>
> +
> +static void __attribute__ ((constructor))
> +init (void)
> +{
> + puts ("info: tst-dlmopen-twice-mod2.so loaded");
> + fflush (stdout);
> +}
> +
> +static void __attribute__ ((destructor))
> +fini (void)
> +{
> + puts ("info: tst-dlmopen-twice-mod2.so about to be unloaded");
> + fflush (stdout);
> +}
> +
> +int
> +run_check (void)
> +{
> + puts ("info: about to call isalpha");
> + fflush (stdout);
> +
> + volatile char ch = 'a';
> + if (!isalpha (ch))
> + {
> + puts ("error: isalpha ('a') is not true");
> + fflush (stdout);
> + return 1;
> + }
> + return 0;
> +}
> diff --git a/elf/tst-dlmopen-twice.c b/elf/tst-dlmopen-twice.c
> new file mode 100644
> index 0000000000..449f3c8fa9
> --- /dev/null
> +++ b/elf/tst-dlmopen-twice.c
> @@ -0,0 +1,34 @@
> +/* Initialization of libc after dlmopen/dlclose/dlmopen (bug 29528). Main.
> + 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 <support/xdlfcn.h>
> +#include <support/check.h>
> +
> +static int
> +do_test (void)
> +{
> + void *handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod1.so", RTLD_NOW);
> + xdlclose (handle);
> + handle = xdlmopen (LM_ID_NEWLM, "tst-dlmopen-twice-mod2.so", RTLD_NOW);
> + int (*run_check) (void) = xdlsym (handle, "run_check");
> + TEST_COMPARE (run_check (), 0);
> + xdlclose (handle);
> + return 0;
> +}
> +
> +#include <support/test-driver.c>
>
> base-commit: 5ecc98241229d494aaad23a4a3fe106fe11e1f40
>
--
H.J.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] elf: Call __libc_early_init for reused namespaces (bug 29528)
2022-08-26 17:57 ` H.J. Lu
@ 2022-08-26 18:11 ` Florian Weimer
0 siblings, 0 replies; 3+ messages in thread
From: Florian Weimer @ 2022-08-26 18:11 UTC (permalink / raw)
To: H.J. Lu; +Cc: GNU C Library
* H. J. Lu:
>> +static void __attribute__ ((constructor))
>> +init (void)
>> +{
>> + puts ("info: tst-dlmopen-twice-mod2.so loaded");
>
> Did you mean tst-dlmopen-twice-mod1.so?
>
>> + fflush (stdout);
>> +}
>> +
>> +static void __attribute__ ((destructor))
>> +fini (void)
>> +{
>> + puts ("info: tst-dlmopen-twice-mod2.so about to be unloaded");
>
> Likewise.
Thanks, I've sen't a second version.
Florian
^ permalink raw reply [flat|nested] 3+ messages in thread
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2022-08-26 12:45 [PATCH] elf: Call __libc_early_init for reused namespaces (bug 29528) Florian Weimer
2022-08-26 17:57 ` H.J. Lu
2022-08-26 18:11 ` Florian Weimer
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