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authorBob Copeland <me@bobcopeland.com>2008-08-15 00:40:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2008-08-15 08:35:44 -0700
commit9419fc1c957d600093baaea247fef23cca3b4e93 (patch)
tree532606ac97d86d8952ffcdd8f8513b1499c10bf8 /fs/omfs/file.c
parentc963343a1150106819773e828c9b237ed977615b (diff)
downloadlinux-9419fc1c957d600093baaea247fef23cca3b4e93.tar.bz2
omfs: fix oops when file metadata is corrupted
A fuzzed fileystem image failed with OMFS when the extent count was used in a loop without being checked against the max number of extents. It also provoked a signed division for an array index that was checked as if unsigned, leading to index by -1. omfsck will be updated to fix these cases, in the meantime bail out gracefully. Reported-by: Eric Sesterhenn <snakebyte@gmx.de> Signed-off-by: Bob Copeland <me@bobcopeland.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'fs/omfs/file.c')
-rw-r--r--fs/omfs/file.c33
1 files changed, 26 insertions, 7 deletions
diff --git a/fs/omfs/file.c b/fs/omfs/file.c
index 7e2499053e4d..834b2331f6b3 100644
--- a/fs/omfs/file.c
+++ b/fs/omfs/file.c
@@ -26,6 +26,13 @@ static int omfs_sync_file(struct file *file, struct dentry *dentry,
return err ? -EIO : 0;
}
+static u32 omfs_max_extents(struct omfs_sb_info *sbi, int offset)
+{
+ return (sbi->s_sys_blocksize - offset -
+ sizeof(struct omfs_extent)) /
+ sizeof(struct omfs_extent_entry) + 1;
+}
+
void omfs_make_empty_table(struct buffer_head *bh, int offset)
{
struct omfs_extent *oe = (struct omfs_extent *) &bh->b_data[offset];
@@ -45,6 +52,7 @@ int omfs_shrink_inode(struct inode *inode)
struct buffer_head *bh;
u64 next, last;
u32 extent_count;
+ u32 max_extents;
int ret;
/* traverse extent table, freeing each entry that is greater
@@ -62,15 +70,18 @@ int omfs_shrink_inode(struct inode *inode)
goto out;
oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
+ max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
for (;;) {
- if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next)) {
- brelse(bh);
- goto out;
- }
+ if (omfs_is_bad(sbi, (struct omfs_header *) bh->b_data, next))
+ goto out_brelse;
extent_count = be32_to_cpu(oe->e_extent_count);
+
+ if (extent_count > max_extents)
+ goto out_brelse;
+
last = next;
next = be64_to_cpu(oe->e_next);
entry = &oe->e_entry;
@@ -98,10 +109,14 @@ int omfs_shrink_inode(struct inode *inode)
if (!bh)
goto out;
oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
+ max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
}
ret = 0;
out:
return ret;
+out_brelse:
+ brelse(bh);
+ return ret;
}
static void omfs_truncate(struct inode *inode)
@@ -154,9 +169,7 @@ static int omfs_grow_extent(struct inode *inode, struct omfs_extent *oe,
goto out;
}
}
- max_count = (sbi->s_sys_blocksize - OMFS_EXTENT_START -
- sizeof(struct omfs_extent)) /
- sizeof(struct omfs_extent_entry) + 1;
+ max_count = omfs_max_extents(sbi, OMFS_EXTENT_START);
/* TODO: add a continuation block here */
if (be32_to_cpu(oe->e_extent_count) > max_count-1)
@@ -225,6 +238,7 @@ static int omfs_get_block(struct inode *inode, sector_t block,
sector_t next, offset;
int ret;
u64 new_block;
+ u32 max_extents;
int extent_count;
struct omfs_extent *oe;
struct omfs_extent_entry *entry;
@@ -238,6 +252,7 @@ static int omfs_get_block(struct inode *inode, sector_t block,
goto out;
oe = (struct omfs_extent *)(&bh->b_data[OMFS_EXTENT_START]);
+ max_extents = omfs_max_extents(sbi, OMFS_EXTENT_START);
next = inode->i_ino;
for (;;) {
@@ -249,6 +264,9 @@ static int omfs_get_block(struct inode *inode, sector_t block,
next = be64_to_cpu(oe->e_next);
entry = &oe->e_entry;
+ if (extent_count > max_extents)
+ goto out_brelse;
+
offset = find_block(inode, entry, block, extent_count, &remain);
if (offset > 0) {
ret = 0;
@@ -266,6 +284,7 @@ static int omfs_get_block(struct inode *inode, sector_t block,
if (!bh)
goto out;
oe = (struct omfs_extent *) (&bh->b_data[OMFS_EXTENT_CONT]);
+ max_extents = omfs_max_extents(sbi, OMFS_EXTENT_CONT);
}
if (create) {
ret = omfs_grow_extent(inode, oe, &new_block);