mm: and drivers core: Convert hugetlb_report_node_meminfo to sysfs_emit

mainline inclusion
from mainline-v5.10-rc1
commit 7981593b
category: bugfix
bugzilla: https://gitee.com/src-openeuler/kernel/issues/I5C32F
CVE: CVE-2022-20166

--------------------------------------------------

Convert the unbound sprintf in hugetlb_report_node_meminfo to use
sysfs_emit_at so that no possible overrun of a PAGE_SIZE buf can occur.
Signed-off-by: NJoe Perches <joe@perches.com>
Acked-by: NMike Kravetz <mike.kravetz@oracle.com>
Link: https://lore.kernel.org/r/894b351b82da6013cde7f36ff4b5493cd0ec30d0.1600285923.git.joe@perches.comSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
	drivers/base/node.c
	include/linux/hugetlb.h
Signed-off-by: NGuo Mengqi <guomengqi3@huawei.com>
Reviewed-by: NWeilong Chen <chenweilong@huawei.com>
Reviewed-by: NXiu Jianfeng <xiujianfeng@huawei.com>
Signed-off-by: NYongqiang Liu <liuyongqiang13@huawei.com>

drivers/base/node.c

@@ -453,7 +453,7 @@ static ssize_t node_read_meminfo(struct device *dev,
 #else
 		       nid, K(node_page_state(pgdat, NR_SLAB_UNRECLAIMABLE)));
 #endif
-	len += hugetlb_report_node_meminfo(nid, buf + len);
+	len += hugetlb_report_node_meminfo(buf, len, nid);
 	return len;
 }
 

include/linux/hugetlb.h

@@ -102,7 +102,7 @@ void __unmap_hugepage_range(struct mmu_gather *tlb, struct vm_area_struct *vma,
 				unsigned long start, unsigned long end,
 				struct page *ref_page);
 void hugetlb_report_meminfo(struct seq_file *);
-int hugetlb_report_node_meminfo(int, char *);
+int hugetlb_report_node_meminfo(char *buf, int len, int nid);
 void hugetlb_show_meminfo(void);
 unsigned long hugetlb_total_pages(void);
 vm_fault_t hugetlb_fault(struct mm_struct *mm, struct vm_area_struct *vma,
@@ -188,7 +188,7 @@ static inline void adjust_range_if_pmd_sharing_possible(
 static inline void hugetlb_report_meminfo(struct seq_file *m)
 {
 }
-#define hugetlb_report_node_meminfo(n, buf)	0
+#define hugetlb_report_node_meminfo(buf, len, nid)	0
 static inline void hugetlb_show_meminfo(void)
 {
 }

mm/hugetlb.c

@@ -3417,12 +3417,14 @@ void hugetlb_report_meminfo(struct seq_file *m)
 	seq_printf(m, "Hugetlb:        %8lu kB\n", total / 1024);
 }
 
-int hugetlb_report_node_meminfo(int nid, char *buf)
+int hugetlb_report_node_meminfo(char *buf, int len, int nid)
 {
 	struct hstate *h = &default_hstate;
+
 	if (!hugepages_supported())
 		return 0;
-	return sprintf(buf,
+
+	return sysfs_emit_at(buf, len,
 			     "Node %d HugePages_Total: %5u\n"
 			     "Node %d HugePages_Free:  %5u\n"
 			     "Node %d HugePages_Surp:  %5u\n",