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authorAneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>2007-10-17 02:27:02 -0400
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-10-17 11:42:52 -0400
commit7c9e69faa28027913ee059c285a5ea8382e24b5d (patch)
tree951e6e780da734c61337eb8fef23ac3ad68b1e18 /fs/ext2/balloc.c
parent82df39738ba9e02c057fa99b7461a56117d36119 (diff)
ext2/ext3/ext4: add block bitmap validation
When a new block bitmap is read from disk in read_block_bitmap() there are a few bits that should ALWAYS be set. In particular, the blocks given by ext4_blk_bitmap, ext4_inode_bitmap and ext4_inode_table. Validate the block bitmap against these blocks. [akpm@linux-foundation.org: cleanups] Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com> Signed-off-by: Andreas Dilger <adilger@clusterfs.com> Acked-by: Mingming Cao <cmm@us.ibm.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/ext2/balloc.c')
-rw-r--r--fs/ext2/balloc.c56
1 files changed, 44 insertions, 12 deletions
diff --git a/fs/ext2/balloc.c b/fs/ext2/balloc.c
index 834ad4c16e2d..ffaa6d845442 100644
--- a/fs/ext2/balloc.c
+++ b/fs/ext2/balloc.c
@@ -69,6 +69,14 @@ struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
69 return desc + offset; 69 return desc + offset;
70} 70}
71 71
72static inline int
73block_in_use(unsigned long block, struct super_block *sb, unsigned char *map)
74{
75 return ext2_test_bit ((block -
76 le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block)) %
77 EXT2_BLOCKS_PER_GROUP(sb), map);
78}
79
72/* 80/*
73 * Read the bitmap for a given block_group, reading into the specified 81 * Read the bitmap for a given block_group, reading into the specified
74 * slot in the superblock's bitmap cache. 82 * slot in the superblock's bitmap cache.
@@ -78,20 +86,51 @@ struct ext2_group_desc * ext2_get_group_desc(struct super_block * sb,
78static struct buffer_head * 86static struct buffer_head *
79read_block_bitmap(struct super_block *sb, unsigned int block_group) 87read_block_bitmap(struct super_block *sb, unsigned int block_group)
80{ 88{
89 int i;
81 struct ext2_group_desc * desc; 90 struct ext2_group_desc * desc;
82 struct buffer_head * bh = NULL; 91 struct buffer_head * bh = NULL;
83 92 unsigned int bitmap_blk;
93
84 desc = ext2_get_group_desc (sb, block_group, NULL); 94 desc = ext2_get_group_desc (sb, block_group, NULL);
85 if (!desc) 95 if (!desc)
86 goto error_out; 96 return NULL;
87 bh = sb_bread(sb, le32_to_cpu(desc->bg_block_bitmap)); 97 bitmap_blk = le32_to_cpu(desc->bg_block_bitmap);
98 bh = sb_bread(sb, bitmap_blk);
88 if (!bh) 99 if (!bh)
89 ext2_error (sb, "read_block_bitmap", 100 ext2_error (sb, __FUNCTION__,
90 "Cannot read block bitmap - " 101 "Cannot read block bitmap - "
91 "block_group = %d, block_bitmap = %u", 102 "block_group = %d, block_bitmap = %u",
92 block_group, le32_to_cpu(desc->bg_block_bitmap)); 103 block_group, le32_to_cpu(desc->bg_block_bitmap));
93error_out: 104
105 /* check whether block bitmap block number is set */
106 if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
107 /* bad block bitmap */
108 goto error_out;
109 }
110 /* check whether the inode bitmap block number is set */
111 bitmap_blk = le32_to_cpu(desc->bg_inode_bitmap);
112 if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
113 /* bad block bitmap */
114 goto error_out;
115 }
116 /* check whether the inode table block number is set */
117 bitmap_blk = le32_to_cpu(desc->bg_inode_table);
118 for (i = 0; i < EXT2_SB(sb)->s_itb_per_group; i++, bitmap_blk++) {
119 if (!block_in_use(bitmap_blk, sb, bh->b_data)) {
120 /* bad block bitmap */
121 goto error_out;
122 }
123 }
124
94 return bh; 125 return bh;
126
127error_out:
128 brelse(bh);
129 ext2_error(sb, __FUNCTION__,
130 "Invalid block bitmap - "
131 "block_group = %d, block = %u",
132 block_group, bitmap_blk);
133 return NULL;
95} 134}
96 135
97/* 136/*
@@ -583,13 +622,6 @@ unsigned long ext2_count_free_blocks (struct super_block * sb)
583#endif 622#endif
584} 623}
585 624
586static inline int
587block_in_use(unsigned long block, struct super_block *sb, unsigned char *map)
588{
589 return ext2_test_bit ((block -
590 le32_to_cpu(EXT2_SB(sb)->s_es->s_first_data_block)) %
591 EXT2_BLOCKS_PER_GROUP(sb), map);
592}
593 625
594static inline int test_root(int a, int b) 626static inline int test_root(int a, int b)
595{ 627{