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authorTheodore Ts'o <tytso@mit.edu>2009-04-22 20:52:25 -0400
committerTheodore Ts'o <tytso@mit.edu>2009-04-22 20:52:25 -0400
commite84a26ce178345498a7eca0590852bcc36f1092f (patch)
treedcd2f95c9f73ffb8d2020fe89bb1c30785e0fa78 /fs
parent38d726d153cfe5efe5fe22d28d36ab382dda3a5c (diff)
ext4: Make the extent validity check more paranoid
Instead of just checking that the extent block number is greater or equal than s_first_data_block, make sure it it is not pointing into the block group descriptors, since that is clearly wrong. This helps prevent filesystem from getting very badly corrupted in case an extent block is corrupted. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs')
-rw-r--r--fs/ext4/extents.c18
1 files changed, 12 insertions, 6 deletions
diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
index 6132353dcf62..c28ffe259506 100644
--- a/fs/ext4/extents.c
+++ b/fs/ext4/extents.c
@@ -326,11 +326,14 @@ ext4_ext_max_entries(struct inode *inode, int depth)
326 326
327static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext) 327static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
328{ 328{
329 ext4_fsblk_t block = ext_pblock(ext); 329 ext4_fsblk_t block = ext_pblock(ext), valid_block;
330 int len = ext4_ext_get_actual_len(ext); 330 int len = ext4_ext_get_actual_len(ext);
331 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es; 331 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
332 if (unlikely(block < le32_to_cpu(es->s_first_data_block) || 332
333 ((block + len) > ext4_blocks_count(es)))) 333 valid_block = le32_to_cpu(es->s_first_data_block) +
334 EXT4_SB(inode->i_sb)->s_gdb_count;
335 if (unlikely(block <= valid_block ||
336 ((block + len) > ext4_blocks_count(es))))
334 return 0; 337 return 0;
335 else 338 else
336 return 1; 339 return 1;
@@ -339,10 +342,13 @@ static int ext4_valid_extent(struct inode *inode, struct ext4_extent *ext)
339static int ext4_valid_extent_idx(struct inode *inode, 342static int ext4_valid_extent_idx(struct inode *inode,
340 struct ext4_extent_idx *ext_idx) 343 struct ext4_extent_idx *ext_idx)
341{ 344{
342 ext4_fsblk_t block = idx_pblock(ext_idx); 345 ext4_fsblk_t block = idx_pblock(ext_idx), valid_block;
343 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es; 346 struct ext4_super_block *es = EXT4_SB(inode->i_sb)->s_es;
344 if (unlikely(block < le32_to_cpu(es->s_first_data_block) || 347
345 (block >= ext4_blocks_count(es)))) 348 valid_block = le32_to_cpu(es->s_first_data_block) +
349 EXT4_SB(inode->i_sb)->s_gdb_count;
350 if (unlikely(block <= valid_block ||
351 (block >= ext4_blocks_count(es))))
346 return 0; 352 return 0;
347 else 353 else
348 return 1; 354 return 1;