[PATCH v2 6/9] ext4: add positive int attr pointer to avoid sysfs variables overflow

Baokun Li
2024-02-27T09:10:11Z

The following variables controlled by the sysfs interface are of type
int and are normally used in the range [0, INT_MAX], but are declared as
attr_pointer_ui, and thus may be set to values that exceed INT_MAX and
result in overflows to get negative values.

err_ratelimit_burst
msg_ratelimit_burst
warning_ratelimit_burst
err_ratelimit_interval_ms
msg_ratelimit_interval_ms
warning_ratelimit_interval_ms

Therefore, we add attr_pointer_pi (aka positive int attr pointer) with a
value range of 0-INT_MAX to avoid overflow.

Signed-off-by: Baokun Li <libaokun1@huawei.com>
---
fs/ext4/sysfs.c | 25 +++++++++++++++++++------
1 file changed, 19 insertions(+), 6 deletions(-)

diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 8e0473169458..ddb54608ca2e 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -32,6 +32,7 @@ typedef enum {
attr_clusters_in_group,
attr_mb_order,
attr_feature,
+ attr_pointer_pi,
attr_pointer_ui,
attr_pointer_ul,
attr_pointer_u64,
@@ -180,6 +181,9 @@ static struct ext4_attr ext4_attr_##_name = { \
#define EXT4_RO_ATTR_ES_STRING(_name,_elname,_size) \
EXT4_ATTR_STRING(_name, 0444, _size, ext4_super_block, _elname)

+#define EXT4_RW_ATTR_SBI_PI(_name,_elname) \
+ EXT4_ATTR_OFFSET(_name, 0644, pointer_pi, ext4_sb_info, _elname)
+
#define EXT4_RW_ATTR_SBI_UI(_name,_elname) \
EXT4_ATTR_OFFSET(_name, 0644, pointer_ui, ext4_sb_info, _elname)

@@ -222,12 +226,12 @@ EXT4_RW_ATTR_SBI_UI(mb_stream_req, s_mb_stream_request);
EXT4_RW_ATTR_SBI_UI(mb_max_linear_groups, s_mb_max_linear_groups);
EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
EXT4_ATTR(trigger_fs_error, 0200, trigger_test_error);
-EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
-EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
-EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
-EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
-EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
-EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
+EXT4_RW_ATTR_SBI_PI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_PI(err_ratelimit_burst, s_err_ratelimit_state.burst);
+EXT4_RW_ATTR_SBI_PI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_PI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
+EXT4_RW_ATTR_SBI_PI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
+EXT4_RW_ATTR_SBI_PI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
#ifdef CONFIG_EXT4_DEBUG
EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail);
#endif
@@ -382,6 +386,7 @@ static ssize_t ext4_generic_attr_show(struct ext4_attr *a,
case attr_inode_readahead:
case attr_clusters_in_group:
case attr_mb_order:
+ case attr_pointer_pi:
case attr_pointer_ui:
if (a->attr_ptr == ptr_ext4_super_block_offset)
return sysfs_emit(buf, "%u\n", le32_to_cpup(ptr));
@@ -452,6 +457,14 @@ static ssize_t ext4_generic_attr_store(struct ext4_attr *a,
return 0;

switch (a->attr_id) {
+ case attr_pointer_pi:
+ ret = kstrtouint(skip_spaces(buf), 0, &t);
+ if (ret)
+ return ret;
+ if ((int)t < 0)
+ return -EINVAL;
+ *((unsigned int *) ptr) = t;
+ return len;
case attr_pointer_ui:
ret = kstrtouint(skip_spaces(buf), 0, &t);
if (ret)
--
2.31.1