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authorEric Sandeen <sandeen@sandeen.net>2019-05-14 15:45:10 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-14 19:52:51 -0700
commit2ea622b887e74497ce5aac5bfe247502b5786f56 (patch)
tree3c17e664a47816f15b10e73a4c31a3dbc6e81b47 /lib/test_sysctl.c
parenta0edef79685c508fde517e6defac23b3ba60c422 (diff)
tools/testing/selftests/sysctl/sysctl.sh: add proc_do_large_bitmap() test case
The kernel has only two users of proc_do_large_bitmap(), the kernel CPU watchdog, and the ip_local_reserved_ports. Refer to watchdog_cpumask and ip_local_reserved_ports in Documentation for further details on these. When you input a large buffer into these, when it is larger than PAGE_SIZE- 1, the input data gets misparsed, and the user get incorrectly informed that the desired input value was set. This commit implements a test which mimics and exploits that use case, it uses a bitmap size, as in the watchdog case. The bitmap is used to test the bitmap proc handler, proc_do_large_bitmap(). The next commit fixes this issue. [akpm@linux-foundation.org: move proc_do_large_bitmap() export to EOF] [mcgrof@kernel.org: use new target description for backward compatibility] [mcgrof@kernel.org: augment test number to 50, ran into issues with bash string comparisons when testing up to 50 cases.] [mcgrof@kernel.org: introduce and use verify_diff_proc_file() to use diff] [mcgrof@kernel.org: use mktemp for tmp file] [mcgrof@kernel.org: merge shell test and C code] [mcgrof@kernel.org: commit log love] [mcgrof@kernel.org: export proc_do_large_bitmap() to allow for the test [mcgrof@kernel.org: check for the return value when writing to the proc file] Link: http://lkml.kernel.org/r/20190320222831.8243-6-mcgrof@kernel.org Signed-off-by: Eric Sandeen <sandeen@redhat.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Acked-by: Kees Cook <keescook@chromium.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'lib/test_sysctl.c')
-rw-r--r--lib/test_sysctl.c18
1 files changed, 17 insertions, 1 deletions
diff --git a/lib/test_sysctl.c b/lib/test_sysctl.c
index 3dd801c1c85b..566dad3f4196 100644
--- a/lib/test_sysctl.c
+++ b/lib/test_sysctl.c
@@ -47,6 +47,9 @@ struct test_sysctl_data {
unsigned int uint_0001;
char string_0001[65];
+
+#define SYSCTL_TEST_BITMAP_SIZE 65536
+ unsigned long *bitmap_0001;
};
static struct test_sysctl_data test_data = {
@@ -102,6 +105,13 @@ static struct ctl_table test_table[] = {
.mode = 0644,
.proc_handler = proc_dostring,
},
+ {
+ .procname = "bitmap_0001",
+ .data = &test_data.bitmap_0001,
+ .maxlen = SYSCTL_TEST_BITMAP_SIZE,
+ .mode = 0644,
+ .proc_handler = proc_do_large_bitmap,
+ },
{ }
};
@@ -129,15 +139,21 @@ static struct ctl_table_header *test_sysctl_header;
static int __init test_sysctl_init(void)
{
+ test_data.bitmap_0001 = kzalloc(SYSCTL_TEST_BITMAP_SIZE/8, GFP_KERNEL);
+ if (!test_data.bitmap_0001)
+ return -ENOMEM;
test_sysctl_header = register_sysctl_table(test_sysctl_root_table);
- if (!test_sysctl_header)
+ if (!test_sysctl_header) {
+ kfree(test_data.bitmap_0001);
return -ENOMEM;
+ }
return 0;
}
late_initcall(test_sysctl_init);
static void __exit test_sysctl_exit(void)
{
+ kfree(test_data.bitmap_0001);
if (test_sysctl_header)
unregister_sysctl_table(test_sysctl_header);
}