@@ -1137,11 +1137,12 @@ static int sysctl_check_table_array(const char *path, const struct ctl_table *ta
return err;
}
-static int sysctl_check_table(const char *path, struct ctl_table_header *header)
+static int sysctl_check_table(const char *path, const struct ctl_table *table,
+ size_t table_size)
{
- const struct ctl_table *entry;
+ const struct ctl_table *entry = table;
int err = 0;
- list_for_each_table_entry(entry, header) {
+ for (size_t i = 0 ; i < table_size; ++i, entry++) {
if (!entry->procname)
err |= sysctl_err(path, entry, "procname is null");
if ((entry->proc_handler == proc_dostring) ||
@@ -1173,6 +1174,16 @@ static int sysctl_check_table(const char *path, struct ctl_table_header *header)
return err;
}
+#ifdef CONFIG_KUNIT
+int sysctl_check_table_test_helper_sz(const char *path,
+ const struct ctl_table *table,
+ size_t table_size)
+{
+ return sysctl_check_table(path, table, table_size);
+}
+EXPORT_SYMBOL(sysctl_check_table_test_helper_sz);
+#endif /* CONFIG_KUNIT */
+
static struct ctl_table_header *new_links(struct ctl_dir *dir, struct ctl_table_header *head)
{
struct ctl_table *link_table, *link;
@@ -1372,6 +1383,9 @@ struct ctl_table_header *__register_sysctl_table(
struct ctl_dir *dir;
struct ctl_node *node;
+ if (sysctl_check_table(path, table, table_size))
+ return NULL;
+
header = kzalloc(sizeof(struct ctl_table_header) +
sizeof(struct ctl_node)*table_size, GFP_KERNEL_ACCOUNT);
if (!header)
@@ -1379,8 +1393,6 @@ struct ctl_table_header *__register_sysctl_table(
node = (struct ctl_node *)(header + 1);
init_header(header, root, set, node, table, table_size);
- if (sysctl_check_table(path, header))
- goto fail;
spin_lock(&sysctl_lock);
dir = &set->dir;
@@ -247,6 +247,14 @@ extern int unaligned_enabled;
extern int unaligned_dump_stack;
extern int no_unaligned_warning;
+#ifdef CONFIG_KUNIT
+int sysctl_check_table_test_helper_sz(const char *path,
+ const struct ctl_table *table,
+ size_t table_size);
+#define sysctl_check_table_test_helper(path, table) \
+ sysctl_check_table_test_helper_sz(path, table, ARRAY_SIZE(table))
+#endif /* CONFIG_KUNIT */
+
#else /* CONFIG_SYSCTL */
static inline void register_sysctl_init(const char *path, const struct ctl_table *table)
@@ -410,9 +410,12 @@ static void sysctl_test_register_sysctl_sz_invalid_extra_value(
},
};
- KUNIT_EXPECT_NULL(test, register_sysctl("foo", table_foo));
- KUNIT_EXPECT_NULL(test, register_sysctl("foo", table_bar));
- KUNIT_EXPECT_NOT_NULL(test, register_sysctl("foo", table_qux));
+ KUNIT_EXPECT_EQ(test, -EINVAL,
+ sysctl_check_table_test_helper("foo", table_foo));
+ KUNIT_EXPECT_EQ(test, -EINVAL,
+ sysctl_check_table_test_helper("foo", table_bar));
+ KUNIT_EXPECT_EQ(test, 0,
+ sysctl_check_table_test_helper("foo", table_qux));
}
static struct kunit_case sysctl_test_cases[] = {
In commit b5ffbd139688 ("sysctl: move the extra1/2 boundary check of u8 to sysctl_check_table_array"), a kunit test was added that registers a sysctl table. If the test is run as a module, then a lingering reference to the module is left behind, and a 'sysctl -a' leads to a panic. This can be reproduced with these kernel config settings: CONFIG_KUNIT=y CONFIG_SYSCTL_KUNIT_TEST=m Then run these commands: modprobe sysctl-test rmmod sysctl-test sysctl -a The panic varies but generally looks something like this: BUG: unable to handle page fault for address: ffffa4571c0c7db4 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 100000067 P4D 100000067 PUD 100351067 PMD 114f5e067 PTE 0 Oops: Oops: 0000 [#1] SMP NOPTI ... ... ... RIP: 0010:proc_sys_readdir+0x166/0x2c0 ... ... ... Call Trace: <TASK> iterate_dir+0x6e/0x140 __se_sys_getdents+0x6e/0x100 do_syscall_64+0x70/0x150 entry_SYSCALL_64_after_hwframe+0x76/0x7e Instead of fully registering a sysctl table, expose the underlying checking function and use it in the unit test. Fixes: b5ffbd139688 ("sysctl: move the extra1/2 boundary check of u8 to sysctl_check_table_array") Signed-off-by: John Sperbeck <jsperbeck@google.com> --- fs/proc/proc_sysctl.c | 22 +++++++++++++++++----- include/linux/sysctl.h | 8 ++++++++ kernel/sysctl-test.c | 9 ++++++--- 3 files changed, 31 insertions(+), 8 deletions(-)