From: Roman Smirnov <r.smirnov@xxxxxx> [ 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> --- fs/udf/balloc.c | 36 +++++++++++++----------------------- 1 file changed, 13 insertions(+), 23 deletions(-) diff --git a/fs/udf/balloc.c b/fs/udf/balloc.c index f416b7fe092fc..aeaa6d1f0e015 100644 --- a/fs/udf/balloc.c +++ b/fs/udf/balloc.c @@ -22,6 +22,7 @@ #include "udfdecl.h" #include <linux/bitops.h> +#include <linux/overflow.h> #include "udf_i.h" #include "udf_sb.h" @@ -133,7 +134,6 @@ 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; @@ -142,19 +142,9 @@ 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); @@ -384,7 +374,6 @@ 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; @@ -393,16 +382,6 @@ 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); @@ -677,6 +656,17 @@ 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, -- 2.43.0
