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authorSiddhesh Poyarekar <siddhesh@sourceware.org>2017-01-20 00:45:09 +0530
committerSiddhesh Poyarekar <siddhesh@sourceware.org>2017-01-20 00:45:09 +0530
commit41389c40499a083c59e68ba281ec87be567f2871 (patch)
tree4d5ff86fc8a5216850383149fbe35944c32adb69 /stdlib
parent3a66b2b0637e439fb0e7a14c6c3d4c58190eec61 (diff)
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Fix environment traversal when an envvar value is empty
The condition when the value of an envvar is empty (not just '\0'), the loop in tunables_init gets stuck infinitely because envp is not incremented. Fix that by always incrementing envp in the loop. Added test case (tst-empty-env.c) verifies the fix when the source is configured with --enable-hardcoded-path-in-tests, thanks Josh Stone for providing the test case. Verified on x86_64. * elf/dl-tunables (get_next_env): Always advance envp. * stdlib/tst-empty-env.c: New test case. * stdlib/Makefile (tests): Use it.
Diffstat (limited to 'stdlib')
-rw-r--r--stdlib/Makefile3
-rw-r--r--stdlib/tst-empty-env.c58
2 files changed, 61 insertions, 0 deletions
diff --git a/stdlib/Makefile b/stdlib/Makefile
index 0c099733fe..5751b5d600 100644
--- a/stdlib/Makefile
+++ b/stdlib/Makefile
@@ -81,6 +81,9 @@ tests := tst-strtol tst-strtod testmb testrand testsort testdiv \
tst-quick_exit tst-thread-quick_exit tst-width \
tst-width-stdint tst-strfrom tst-strfrom-locale \
tst-getrandom
+ifeq ($(build-hardcoded-path-in-tests),yes)
+tests += tst-empty-env
+endif
tests-static := tst-secure-getenv
ifeq ($(have-cxx-thread_local),yes)
CFLAGS-tst-quick_exit.o = -std=c++11
diff --git a/stdlib/tst-empty-env.c b/stdlib/tst-empty-env.c
new file mode 100644
index 0000000000..0b0651d530
--- /dev/null
+++ b/stdlib/tst-empty-env.c
@@ -0,0 +1,58 @@
+/* Test that passing a NULL value does not hang environment traversal in
+ tunables.
+ Copyright (C) 2017 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
+ <http://www.gnu.org/licenses/>. */
+
+/* The test is useful only when the source is configured with
+ --enable-hardcoded-path-in-tests since otherwise the execve just picks up
+ the system dynamic linker. */
+
+#include <stdlib.h>
+#include <stdio.h>
+#include <unistd.h>
+#include <errno.h>
+
+static int
+do_test (int argc, char **argv)
+{
+ if (argc == 2)
+ return 0;
+
+ char envname[] = "FOOBAR";
+ char *filename = program_invocation_name;
+ char *newargv[] = {filename, filename, NULL};
+ char *newenviron[] = {envname, NULL};
+
+ /* This was reported in Fedora:
+
+ https://bugzilla.redhat.com/show_bug.cgi?id=1414589
+
+ If one of the environment variables has no value, then the environment
+ traversal must skip and also advance to the next environment entry. The
+ bug in question would cause this test to hang in an infinite loop. */
+ int ret = execve (filename, newargv, newenviron);
+
+ if (ret != 0)
+ printf ("execve failed: %m");
+
+ /* We will reach here only if we fail execve. */
+ return 1;
+}
+
+#define TIMEOUT 3
+#define TEST_FUNCTION_ARGV do_test
+#include <support/test-driver.c>