Avoid beyond bounds copy while caching ACL
When attempting to cache ACLs returned from the server, if the bitmap
size + the ACL size is greater than a PAGE_SIZE but the ACL size itself
is smaller than a PAGE_SIZE, we can read past the buffer page boundary.
Signed-off-by: Sachin Prabhu <sprabhu@redhat.com>
Reported-by: Jian Li <jiali@redhat.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index f5f125f..2ce0698 100644
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -3628,16 +3628,16 @@
return ret;
}
-static void nfs4_write_cached_acl(struct inode *inode, const char *buf, size_t acl_len)
+static void nfs4_write_cached_acl(struct inode *inode, struct page **pages, size_t pgbase, size_t acl_len)
{
struct nfs4_cached_acl *acl;
- if (buf && acl_len <= PAGE_SIZE) {
+ if (pages && acl_len <= PAGE_SIZE) {
acl = kmalloc(sizeof(*acl) + acl_len, GFP_KERNEL);
if (acl == NULL)
goto out;
acl->cached = 1;
- memcpy(acl->data, buf, acl_len);
+ _copy_from_pages(acl->data, pages, pgbase, acl_len);
} else {
acl = kmalloc(sizeof(*acl), GFP_KERNEL);
if (acl == NULL)
@@ -3670,7 +3670,6 @@
struct nfs_getaclres res = {
.acl_len = buflen,
};
- void *resp_buf;
struct rpc_message msg = {
.rpc_proc = &nfs4_procedures[NFSPROC4_CLNT_GETACL],
.rpc_argp = &args,
@@ -3705,7 +3704,6 @@
* the page we send as a guess */
if (buf == NULL)
res.acl_flags |= NFS4_ACL_LEN_REQUEST;
- resp_buf = page_address(pages[0]);
dprintk("%s buf %p buflen %zu npages %d args.acl_len %zu\n",
__func__, buf, buflen, npages, args.acl_len);
@@ -3716,9 +3714,9 @@
acl_len = res.acl_len - res.acl_data_offset;
if (acl_len > args.acl_len)
- nfs4_write_cached_acl(inode, NULL, acl_len);
+ nfs4_write_cached_acl(inode, NULL, 0, acl_len);
else
- nfs4_write_cached_acl(inode, resp_buf + res.acl_data_offset,
+ nfs4_write_cached_acl(inode, pages, res.acl_data_offset,
acl_len);
if (buf) {
ret = -ERANGE;