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authorJan Kara <jack@suse.cz>2014-12-15 14:22:46 +0100
committerJan Kara <jack@suse.cz>2014-12-15 15:53:26 +0100
commitf54e18f1b831c92f6512d2eedb224cd63d607d3d (patch)
tree5b24ced61a9bda1f5ae41196a39a96c88b19229b
parentfa0c5540739320258c3e3a45aaae9dae467b2504 (diff)
isofs: Fix infinite looping over CE entries
Rock Ridge extensions define so called Continuation Entries (CE) which define where is further space with Rock Ridge data. Corrupted isofs image can contain arbitrarily long chain of these, including a one containing loop and thus causing kernel to end in an infinite loop when traversing these entries. Limit the traversal to 32 entries which should be more than enough space to store all the Rock Ridge data. Reported-by: P J P <ppandit@redhat.com> CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz>
-rw-r--r--fs/isofs/rock.c6
1 files changed, 6 insertions, 0 deletions
diff --git a/fs/isofs/rock.c b/fs/isofs/rock.c
index f488bba..bb63254 100644
--- a/fs/isofs/rock.c
+++ b/fs/isofs/rock.c
@@ -30,6 +30,7 @@ struct rock_state {
int cont_size;
int cont_extent;
int cont_offset;
+ int cont_loops;
struct inode *inode;
};
@@ -73,6 +74,9 @@ static void init_rock_state(struct rock_state *rs, struct inode *inode)
rs->inode = inode;
}
+/* Maximum number of Rock Ridge continuation entries */
+#define RR_MAX_CE_ENTRIES 32
+
/*
* Returns 0 if the caller should continue scanning, 1 if the scan must end
* and -ve on error.
@@ -105,6 +109,8 @@ static int rock_continue(struct rock_state *rs)
goto out;
}
ret = -EIO;
+ if (++rs->cont_loops >= RR_MAX_CE_ENTRIES)
+ goto out;
bh = sb_bread(rs->inode->i_sb, rs->cont_extent);
if (bh) {
memcpy(rs->buffer, bh->b_data + rs->cont_offset,