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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>
This commit is contained in:
Sachin Prabhu 2012-04-17 14:36:40 +01:00 committed by Trond Myklebust
parent 5a00689930
commit 5794d21ef4
2 changed files with 6 additions and 8 deletions
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12
fs/nfs/nfs4proc.c
View File

@ -3628,16 +3628,16 @@ out:
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 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu
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 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu
* 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 @@ static ssize_t __nfs4_get_acl_uncached(struct inode *inode, void *buf, size_t bu
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;

2
fs/nfs/nfs4xdr.c
View File

@ -4940,7 +4940,7 @@ static int decode_getacl(struct xdr_stream *xdr, struct rpc_rqst *req,
res->acl_len = attrlen;
goto out;
}
dprintk("NFS: acl reply: attrlen %zu > page_len %u\n",
dprintk("NFS: acl reply: attrlen %u > page_len %zu\n",
attrlen, page_len);
return -EINVAL;
}