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authorJan Kara <jack@suse.cz>2007-06-01 07:46:29 (GMT)
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2007-06-01 15:18:27 (GMT)
commit85d71244f02583886dc20a60df2d4657d42116b4 (patch)
tree9140675832d488f40f5a4b230ff7c651a598dbf4 /fs
parent296baae254c2e9ead4da5bfa57ecec86750331c7 (diff)
Fix possible UDF data corruption
update_next_aext() could possibly rewrite values in elen and eloc, possibly leading to data corruption when rewriting a file. Use temporary variables instead. Also advance cur_epos as it can also point to an indirect extent pointer. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs')
-rw-r--r--fs/udf/inode.c12
1 files changed, 8 insertions, 4 deletions
diff --git a/fs/udf/inode.c b/fs/udf/inode.c
index c846155..1f01294 100644
--- a/fs/udf/inode.c
+++ b/fs/udf/inode.c
@@ -460,8 +460,8 @@ static struct buffer_head * inode_getblk(struct inode * inode, sector_t block,
kernel_long_ad laarr[EXTENT_MERGE_SIZE];
struct extent_position prev_epos, cur_epos, next_epos;
int count = 0, startnum = 0, endnum = 0;
- uint32_t elen = 0;
- kernel_lb_addr eloc;
+ uint32_t elen = 0, tmpelen;
+ kernel_lb_addr eloc, tmpeloc;
int c = 1;
loff_t lbcount = 0, b_off = 0;
uint32_t newblocknum, newblock;
@@ -520,8 +520,12 @@ static struct buffer_head * inode_getblk(struct inode * inode, sector_t block,
b_off -= lbcount;
offset = b_off >> inode->i_sb->s_blocksize_bits;
- /* Move into indirect extent if we are at a pointer to it */
- udf_next_aext(inode, &prev_epos, &eloc, &elen, 0);
+ /*
+ * Move prev_epos and cur_epos into indirect extent if we are at
+ * the pointer to it
+ */
+ udf_next_aext(inode, &prev_epos, &tmpeloc, &tmpelen, 0);
+ udf_next_aext(inode, &cur_epos, &tmpeloc, &tmpelen, 0);
/* if the extent is allocated and recorded, return the block
if the extent is not a multiple of the blocksize, round up */

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