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

Jan Kara
2024-03-14T10:33:40Z

On Tue 27-02-24 17:11:45, Baokun Li wrote:
> 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>

Looks good. Feel free to add:

Reviewed-by: Jan Kara <jack@suse.cz>

Honza

> ---
> 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
>
--
Jan Kara <jack@suse.com>
SUSE Labs, CR