This is a note to let you know that I've just added the patch titled
udf: prevent integer overflow in udf_bitmap_free_blocks()
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
udf-prevent-integer-overflow-in-udf_bitmap_free_bloc.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 22de9d26fea88d1171ee8243ad720d6a1ebcd15c
Author: Roman Smirnov <r.smirnov@xxxxxx>
Date: Thu Jun 20 10:24:13 2024 +0300
udf: prevent integer overflow in udf_bitmap_free_blocks()
[ Upstream commit 56e69e59751d20993f243fb7dd6991c4e522424c ]
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@xxxxxx
Suggested-by: Jan Kara <jack@xxxxxxxx>
Signed-off-by: Roman Smirnov <r.smirnov@xxxxxx>
Signed-off-by: Jan Kara <jack@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/fs/udf/balloc.c b/fs/udf/balloc.c
index 558ad046972ad..bb471ec364046 100644
--- a/fs/udf/balloc.c
+++ b/fs/udf/balloc.c
@@ -18,6 +18,7 @@
#include "udfdecl.h"
#include <linux/bitops.h>
+#include <linux/overflow.h>
#include "udf_i.h"
#include "udf_sb.h"
@@ -140,7 +141,6 @@ 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;
@@ -149,19 +149,9 @@ 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);
@@ -391,7 +381,6 @@ 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;
@@ -400,16 +389,6 @@ 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);
@@ -684,6 +663,17 @@ 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,
