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udf: prevent integer overflow in udf_bitmap_free_blocks()

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An overflow may occur if the function is called with the last
block and an offset greater than zero. It is necessary to add
a check to avoid this.

Found by Linux Verification Center (linuxtesting.org) with Svace.

[JK: Make test cover also unalloc table freeing]

Link: https://patch.msgid.link/20240620072413.7448-1-r.smirnov@omp.ru
Suggested-by: Jan Kara <jack@suse.com>
Signed-off-by: Roman Smirnov <r.smirnov@omp.ru>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Roman Smirnov 2024-06-20 10:24:13 +03:00 committed by Jan Kara
parent ebbe26fd54
commit 56e69e5975
1 changed files with 13 additions and 23 deletions
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36
fs/udf/balloc.c
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@ -18,6 +18,7 @@
#include "udfdecl.h"
#include <linux/bitops.h>
#include <linux/overflow.h>
#include "udf_i.h"
#include "udf_sb.h"
@ -123,7 +124,6 @@ static void udf_bitmap_free_blocks(struct super_block *sb,
{
struct udf_sb_info *sbi = UDF_SB(sb);
struct buffer_head *bh = NULL;
struct udf_part_map *partmap;
unsigned long block;
unsigned long block_group;
unsigned long bit;
@ -132,19 +132,9 @@ static void udf_bitmap_free_blocks(struct super_block *sb,
unsigned long overflow;
mutex_lock(&sbi->s_alloc_mutex);
partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
if (bloc->logicalBlockNum + count < count ||
(bloc->logicalBlockNum + count) > partmap->s_partition_len) {
udf_debug("%u < %d || %u + %u > %u\n",
bloc->logicalBlockNum, 0,
bloc->logicalBlockNum, count,
partmap->s_partition_len);
goto error_return;
}
/* We make sure this cannot overflow when mounting the filesystem */
block = bloc->logicalBlockNum + offset +
(sizeof(struct spaceBitmapDesc) << 3);
do {
overflow = 0;
block_group = block >> (sb->s_blocksize_bits + 3);
@ -374,7 +364,6 @@ static void udf_table_free_blocks(struct super_block *sb,
uint32_t count)
{
struct udf_sb_info *sbi = UDF_SB(sb);
struct udf_part_map *partmap;
uint32_t start, end;
uint32_t elen;
struct kernel_lb_addr eloc;
@ -383,16 +372,6 @@ static void udf_table_free_blocks(struct super_block *sb,
struct udf_inode_info *iinfo;
mutex_lock(&sbi->s_alloc_mutex);
partmap = &sbi->s_partmaps[bloc->partitionReferenceNum];
if (bloc->logicalBlockNum + count < count ||
(bloc->logicalBlockNum + count) > partmap->s_partition_len) {
udf_debug("%u < %d || %u + %u > %u\n",
bloc->logicalBlockNum, 0,
bloc->logicalBlockNum, count,
partmap->s_partition_len);
goto error_return;
}
iinfo = UDF_I(table);
udf_add_free_space(sb, sbi->s_partition, count);
@ -667,6 +646,17 @@ void udf_free_blocks(struct super_block *sb, struct inode *inode,
{
uint16_t partition = bloc->partitionReferenceNum;
struct udf_part_map *map = &UDF_SB(sb)->s_partmaps[partition];
uint32_t blk;
if (check_add_overflow(bloc->logicalBlockNum, offset, &blk) ||
check_add_overflow(blk, count, &blk) ||
bloc->logicalBlockNum + count > map->s_partition_len) {
udf_debug("Invalid request to free blocks: (%d, %u), off %u, "
"len %u, partition len %u\n",
partition, bloc->logicalBlockNum, offset, count,
map->s_partition_len);
return;
}
if (map->s_partition_flags & UDF_PART_FLAG_UNALLOC_BITMAP) {
udf_bitmap_free_blocks(sb, map->s_uspace.s_bitmap,