[GFS2] Patch to detect corrupt number of dir entries in leaf and/or inode blocks
This patch detects when the number of entries in a leaf block or inode
block (in the case of stuffed directories) is corrupt and informs the
user. It prevents us from running off the end of the array thats been
allocated for the sorting in this case,
Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
diff --git a/fs/gfs2/dir.c b/fs/gfs2/dir.c
index 82a1ac7..6c3ed76 100644
--- a/fs/gfs2/dir.c
+++ b/fs/gfs2/dir.c
@@ -1262,9 +1262,10 @@
u64 leaf_no)
{
struct gfs2_inode *ip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
struct buffer_head *bh;
struct gfs2_leaf *lf;
- unsigned entries = 0;
+ unsigned entries = 0, entries2 = 0;
unsigned leaves = 0;
const struct gfs2_dirent **darr, *dent;
struct dirent_gather g;
@@ -1290,7 +1291,13 @@
return 0;
error = -ENOMEM;
- larr = vmalloc((leaves + entries) * sizeof(void *));
+ /*
+ * The extra 99 entries are not normally used, but are a buffer
+ * zone in case the number of entries in the leaf is corrupt.
+ * 99 is the maximum number of entries that can fit in a single
+ * leaf block.
+ */
+ larr = vmalloc((leaves + entries + 99) * sizeof(void *));
if (!larr)
goto out;
darr = (const struct gfs2_dirent **)(larr + leaves);
@@ -1305,10 +1312,18 @@
lf = (struct gfs2_leaf *)bh->b_data;
lfn = be64_to_cpu(lf->lf_next);
if (lf->lf_entries) {
+ entries2 += be16_to_cpu(lf->lf_entries);
dent = gfs2_dirent_scan(inode, bh->b_data, bh->b_size,
gfs2_dirent_gather, NULL, &g);
error = PTR_ERR(dent);
- if (IS_ERR(dent)) {
+ if (IS_ERR(dent))
+ goto out_kfree;
+ if (entries2 != g.offset) {
+ fs_warn(sdp, "Number of entries corrupt in dir leaf %llu, "
+ "entries2 (%u) != g.offset (%u)\n",
+ (u64)bh->b_blocknr, entries2, g.offset);
+
+ error = -EIO;
goto out_kfree;
}
error = 0;
@@ -1318,6 +1333,7 @@
}
} while(lfn);
+ BUG_ON(entries2 != entries);
error = do_filldir_main(ip, offset, opaque, filldir, darr,
entries, copied);
out_kfree:
@@ -1401,6 +1417,7 @@
filldir_t filldir)
{
struct gfs2_inode *dip = GFS2_I(inode);
+ struct gfs2_sbd *sdp = GFS2_SB(inode);
struct dirent_gather g;
const struct gfs2_dirent **darr, *dent;
struct buffer_head *dibh;
@@ -1423,8 +1440,8 @@
return error;
error = -ENOMEM;
- darr = kmalloc(dip->i_di.di_entries * sizeof(struct gfs2_dirent *),
- GFP_KERNEL);
+ /* 96 is max number of dirents which can be stuffed into an inode */
+ darr = kmalloc(96 * sizeof(struct gfs2_dirent *), GFP_KERNEL);
if (darr) {
g.pdent = darr;
g.offset = 0;
@@ -1434,6 +1451,14 @@
error = PTR_ERR(dent);
goto out;
}
+ if (dip->i_di.di_entries != g.offset) {
+ fs_warn(sdp, "Number of entries corrupt in dir %llu, "
+ "ip->i_di.di_entries (%u) != g.offset (%u)\n",
+ dip->i_num.no_addr, dip->i_di.di_entries,
+ g.offset);
+ error = -EIO;
+ goto out;
+ }
error = do_filldir_main(dip, offset, opaque, filldir, darr,
dip->i_di.di_entries, &copied);
out: