2008-02-07 06:22:18

by David Teigland

[permalink] [raw]
Subject: [PATCH 10/16] dlm: make find_rsb() fail gracefully when namelen is too large

From: Al Viro <[email protected]>

We *can* get there from receive_request() and dlm_recover_master_copy()
with namelen too large if incoming request is invalid; BUG() from
DLM_ASSERT() in allocate_rsb() is a bit excessive reaction to that
and in case of dlm_recover_master_copy() we would actually oops before
that while calculating hash of up to 64Kb worth of data - with data
actually being 64 _bytes_ in kmalloc()'ed struct.

Signed-off-by: Al Viro <[email protected]>
Signed-off-by: David Teigland <[email protected]>
---
fs/dlm/lock.c | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/fs/dlm/lock.c b/fs/dlm/lock.c
index 0593dd8..6d98cf9 100644
--- a/fs/dlm/lock.c
+++ b/fs/dlm/lock.c
@@ -436,11 +436,15 @@ static int find_rsb(struct dlm_ls *ls, char *name, int namelen,
{
struct dlm_rsb *r, *tmp;
uint32_t hash, bucket;
- int error = 0;
+ int error = -EINVAL;
+
+ if (namelen > DLM_RESNAME_MAXLEN)
+ goto out;

if (dlm_no_directory(ls))
flags |= R_CREATE;

+ error = 0;
hash = jhash(name, namelen, 0);
bucket = hash & (ls->ls_rsbtbl_size - 1);

--
1.5.3.3