path: root/fs/dlm/user.c
diff options
authorSasha Levin <levinsasha928@gmail.com>2012-09-09 16:16:58 +0200
committerDavid Teigland <teigland@redhat.com>2012-09-10 09:50:27 -0500
commit2b75bc9121e54e22537207b47b71373bcb0be41c (patch)
tree1b2778a163dedd71cd968b3b4e1d2049b5a86319 /fs/dlm/user.c
parent9c5bef5849c9fde1a37ac005299f759440cbaf4c (diff)
dlm: check the maximum size of a request from user
device_write only checks whether the request size is big enough, but it doesn't check if the size is too big. At that point, it also tries to allocate as much memory as the user has requested even if it's too much. This can lead to OOM killer kicking in, or memory corruption if (count + 1) overflows. Signed-off-by: Sasha Levin <levinsasha928@gmail.com> Signed-off-by: David Teigland <teigland@redhat.com>
Diffstat (limited to 'fs/dlm/user.c')
1 files changed, 7 insertions, 0 deletions
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index eb4ed9ba309..7ff49852b0c 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -503,6 +503,13 @@ static ssize_t device_write(struct file *file, const char __user *buf,
return -EINVAL;
+ if (count > sizeof(struct dlm_write_request32) + DLM_RESNAME_MAXLEN)
+ if (count > sizeof(struct dlm_write_request) + DLM_RESNAME_MAXLEN)
+ return -EINVAL;
kbuf = kzalloc(count + 1, GFP_NOFS);
if (!kbuf)
return -ENOMEM;