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NFSD: Add an xdr_stream-based decoder for NFSv2/3 ACLs 

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2020-11-17 10:38:46 -05:00
parent 635a45d347
commit 6bb844b4eb
2 changed files with 55 additions and 0 deletions
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52
fs/nfs_common/nfsacl.c
View File

@ -295,3 +295,55 @@ int nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
nfsacl_desc.desc.array_len;
}
EXPORT_SYMBOL_GPL(nfsacl_decode);
/**
* nfs_stream_decode_acl - Decode an NFSv3 ACL
*
* @xdr: an xdr_stream positioned at an encoded ACL
* @aclcnt: OUT: count of ACEs in decoded posix_acl
* @pacl: OUT: a dynamically-allocated buffer containing the decoded posix_acl
*
* Return values:
* %false: The encoded ACL is not valid
* %true: @pacl contains a decoded ACL, and @xdr is advanced
*
* On a successful return, caller must release *pacl using posix_acl_release().
*/
bool nfs_stream_decode_acl(struct xdr_stream *xdr, unsigned int *aclcnt,
struct posix_acl **pacl)
{
const size_t elem_size = XDR_UNIT * 3;
struct nfsacl_decode_desc nfsacl_desc = {
.desc = {
.elem_size = elem_size,
.xcode = pacl ? xdr_nfsace_decode : NULL,
},
};
unsigned int base;
u32 entries;
if (xdr_stream_decode_u32(xdr, &entries) < 0)
return false;
if (entries > NFS_ACL_MAX_ENTRIES)
return false;
base = xdr_stream_pos(xdr);
if (!xdr_inline_decode(xdr, XDR_UNIT + elem_size * entries))
return false;
nfsacl_desc.desc.array_maxlen = entries;
if (xdr_decode_array2(xdr->buf, base, &nfsacl_desc.desc))
return false;
if (pacl) {
if (entries != nfsacl_desc.desc.array_len ||
posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) {
posix_acl_release(nfsacl_desc.acl);
return false;
}
*pacl = nfsacl_desc.acl;
}
if (aclcnt)
*aclcnt = entries;
return true;
}
EXPORT_SYMBOL_GPL(nfs_stream_decode_acl);

3
include/linux/nfsacl.h
View File

@ -38,5 +38,8 @@ nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
extern int
nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
struct posix_acl **pacl);
extern bool
nfs_stream_decode_acl(struct xdr_stream *xdr, unsigned int *aclcnt,
struct posix_acl **pacl);
#endif /* __LINUX_NFSACL_H */