From: Baokun Li libaokun1@huawei.com
mainline inclusion from mainline-v6.10-rc1 commit b7b2a5799b8fafe95fcd5455c32ba2c643c86f99 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IAD018 CVE: CVE-2024-40955
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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The s_mb_best_avail_max_trim_order is of type unsigned int, and has a range of values well beyond the normal use of the mb_order. Although the mballoc code is careful enough that large numbers don't matter there, but this can mislead the sysadmin into thinking that it's normal to set such values. Hence add a new attr_id attr_mb_order with values in the range [0, 64] to avoid storing garbage values and make us more resilient to surprises in the future.
Suggested-by: Jan Kara jack@suse.cz Signed-off-by: Baokun Li libaokun1@huawei.com Reviewed-by: Jan Kara jack@suse.cz Link: https://lore.kernel.org/r/20240319113325.3110393-6-libaokun1@huawei.com Signed-off-by: Theodore Ts'o tytso@mit.edu Signed-off-by: Yifan Qiao qiaoyifan4@huawei.com --- fs/ext4/sysfs.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c index ddd71673176c..8e0473169458 100644 --- a/fs/ext4/sysfs.c +++ b/fs/ext4/sysfs.c @@ -30,6 +30,7 @@ typedef enum { attr_first_error_time, attr_last_error_time, attr_clusters_in_group, + attr_mb_order, attr_feature, attr_pointer_ui, attr_pointer_ul, @@ -210,6 +211,8 @@ EXT4_ATTR_OFFSET(inode_readahead_blks, 0644, inode_readahead, ext4_sb_info, s_inode_readahead_blks); EXT4_ATTR_OFFSET(mb_group_prealloc, 0644, clusters_in_group, ext4_sb_info, s_mb_group_prealloc); +EXT4_ATTR_OFFSET(mb_best_avail_max_trim_order, 0644, mb_order, + ext4_sb_info, s_mb_best_avail_max_trim_order); EXT4_RW_ATTR_SBI_UI(inode_goal, s_inode_goal); EXT4_RW_ATTR_SBI_UI(mb_stats, s_mb_stats); EXT4_RW_ATTR_SBI_UI(mb_max_to_scan, s_mb_max_to_scan); @@ -225,7 +228,6 @@ EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.int 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_UI(mb_best_avail_max_trim_order, s_mb_best_avail_max_trim_order); #ifdef CONFIG_EXT4_DEBUG EXT4_RW_ATTR_SBI_UL(simulate_fail, s_simulate_fail); #endif @@ -379,6 +381,7 @@ static ssize_t ext4_generic_attr_show(struct ext4_attr *a, switch (a->attr_id) { case attr_inode_readahead: case attr_clusters_in_group: + case attr_mb_order: case attr_pointer_ui: if (a->attr_ptr == ptr_ext4_super_block_offset) return sysfs_emit(buf, "%u\n", le32_to_cpup(ptr)); @@ -458,6 +461,14 @@ static ssize_t ext4_generic_attr_store(struct ext4_attr *a, else *((unsigned int *) ptr) = t; return len; + case attr_mb_order: + ret = kstrtouint(skip_spaces(buf), 0, &t); + if (ret) + return ret; + if (t > 64) + return -EINVAL; + *((unsigned int *) ptr) = t; + return len; case attr_clusters_in_group: ret = kstrtouint(skip_spaces(buf), 0, &t); if (ret)