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authorPatrick Caulfeld <pcaulfie@redhat.com>2008-01-17 10:25:28 +0000
committerDavid Teigland <teigland@redhat.com>2008-01-30 11:04:43 -0600
commit2a79289e87f3b6487b5fd23c8569f32097057fb4 (patch)
tree3b099a7b7306ee99fcb272e260b7344d34fdc666 /fs
parent85f0379aa0f9366bb6918e2e898a915231176fbd (diff)
downloadlinux-2a79289e87f3b6487b5fd23c8569f32097057fb4.tar.gz
dlm: Sanity check namelen before copying it
The 32/64 compatibility code in the DLM does not check the validity of the lock name length passed into it, so it can easily overwrite memory if the value is rubbish (as early versions of libdlm can cause with unlock calls, it doesn't zero the field). This patch restricts the length of the name to the amount of data actually passed into the call. Signed-off-by: Patrick Caulfield <pcaulfie@redhat.com> Signed-off-by: David Teigland <teigland@redhat.com>
Diffstat (limited to 'fs')
-rw-r--r--fs/dlm/user.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/fs/dlm/user.c b/fs/dlm/user.c
index eb616481694..1acb4c5813c 100644
--- a/fs/dlm/user.c
+++ b/fs/dlm/user.c
@@ -82,7 +82,8 @@ struct dlm_lock_result32 {
};
static void compat_input(struct dlm_write_request *kb,
- struct dlm_write_request32 *kb32)
+ struct dlm_write_request32 *kb32,
+ int max_namelen)
{
kb->version[0] = kb32->version[0];
kb->version[1] = kb32->version[1];
@@ -112,7 +113,11 @@ static void compat_input(struct dlm_write_request *kb,
kb->i.lock.bastaddr = (void *)(long)kb32->i.lock.bastaddr;
kb->i.lock.lksb = (void *)(long)kb32->i.lock.lksb;
memcpy(kb->i.lock.lvb, kb32->i.lock.lvb, DLM_USER_LVB_LEN);
- memcpy(kb->i.lock.name, kb32->i.lock.name, kb->i.lock.namelen);
+ if (kb->i.lock.namelen <= max_namelen)
+ memcpy(kb->i.lock.name, kb32->i.lock.name,
+ kb->i.lock.namelen);
+ else
+ kb->i.lock.namelen = max_namelen;
}
}
@@ -529,7 +534,8 @@ static ssize_t device_write(struct file *file, const char __user *buf,
if (proc)
set_bit(DLM_PROC_FLAGS_COMPAT, &proc->flags);
- compat_input(kbuf, k32buf);
+ compat_input(kbuf, k32buf,
+ count - sizeof(struct dlm_write_request32));
kfree(k32buf);
}
#endif