linux/fs/nfs_common/nfsacl.c

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/*
* fs/nfs_common/nfsacl.c
*
* Copyright (C) 2002-2003 Andreas Gruenbacher <agruen@suse.de>
*/
/*
* The Solaris nfsacl protocol represents some ACLs slightly differently
* than POSIX 1003.1e draft 17 does (and we do):
*
* - Minimal ACLs always have an ACL_MASK entry, so they have
* four instead of three entries.
* - The ACL_MASK entry in such minimal ACLs always has the same
* permissions as the ACL_GROUP_OBJ entry. (In extended ACLs
* the ACL_MASK and ACL_GROUP_OBJ entries may differ.)
* - The identifier fields of the ACL_USER_OBJ and ACL_GROUP_OBJ
* entries contain the identifiers of the owner and owning group.
* (In POSIX ACLs we always set them to ACL_UNDEFINED_ID).
* - ACL entries in the kernel are kept sorted in ascending order
* of (e_tag, e_id). Solaris ACLs are unsorted.
*/
#include <linux/module.h>
#include <linux/fs.h>
include cleanup: Update gfp.h and slab.h includes to prepare for breaking implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-24 08:04:11 +00:00
#include <linux/gfp.h>
#include <linux/sunrpc/xdr.h>
#include <linux/nfsacl.h>
#include <linux/nfs3.h>
#include <linux/sort.h>
MODULE_LICENSE("GPL");
EXPORT_SYMBOL_GPL(nfsacl_encode);
EXPORT_SYMBOL_GPL(nfsacl_decode);
struct nfsacl_encode_desc {
struct xdr_array2_desc desc;
unsigned int count;
struct posix_acl *acl;
int typeflag;
kuid_t uid;
kgid_t gid;
};
struct nfsacl_simple_acl {
struct posix_acl acl;
struct posix_acl_entry ace[4];
};
static int
xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem)
{
struct nfsacl_encode_desc *nfsacl_desc =
(struct nfsacl_encode_desc *) desc;
__be32 *p = elem;
struct posix_acl_entry *entry =
&nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
*p++ = htonl(entry->e_tag | nfsacl_desc->typeflag);
switch(entry->e_tag) {
case ACL_USER_OBJ:
*p++ = htonl(from_kuid(&init_user_ns, nfsacl_desc->uid));
break;
case ACL_GROUP_OBJ:
*p++ = htonl(from_kgid(&init_user_ns, nfsacl_desc->gid));
break;
case ACL_USER:
*p++ = htonl(from_kuid(&init_user_ns, entry->e_uid));
break;
case ACL_GROUP:
*p++ = htonl(from_kgid(&init_user_ns, entry->e_gid));
break;
default: /* Solaris depends on that! */
*p++ = 0;
break;
}
*p++ = htonl(entry->e_perm & S_IRWXO);
return 0;
}
/**
* nfsacl_encode - Encode an NFSv3 ACL
*
* @buf: destination xdr_buf to contain XDR encoded ACL
* @base: byte offset in xdr_buf where XDR'd ACL begins
* @inode: inode of file whose ACL this is
* @acl: posix_acl to encode
* @encode_entries: whether to encode ACEs as well
* @typeflag: ACL type: NFS_ACL_DEFAULT or zero
*
* Returns size of encoded ACL in bytes or a negative errno value.
*/
int nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
struct posix_acl *acl, int encode_entries, int typeflag)
{
int entries = (acl && acl->a_count) ? max_t(int, acl->a_count, 4) : 0;
struct nfsacl_encode_desc nfsacl_desc = {
.desc = {
.elem_size = 12,
.array_len = encode_entries ? entries : 0,
.xcode = xdr_nfsace_encode,
},
.acl = acl,
.typeflag = typeflag,
.uid = inode->i_uid,
.gid = inode->i_gid,
};
struct nfsacl_simple_acl aclbuf;
int err;
if (entries > NFS_ACL_MAX_ENTRIES ||
xdr_encode_word(buf, base, entries))
return -EINVAL;
if (encode_entries && acl && acl->a_count == 3) {
struct posix_acl *acl2 = &aclbuf.acl;
/* Avoid the use of posix_acl_alloc(). nfsacl_encode() is
* invoked in contexts where a memory allocation failure is
* fatal. Fortunately this fake ACL is small enough to
* construct on the stack. */
posix_acl_init(acl2, 4);
/* Insert entries in canonical order: other orders seem
to confuse Solaris VxFS. */
acl2->a_entries[0] = acl->a_entries[0]; /* ACL_USER_OBJ */
acl2->a_entries[1] = acl->a_entries[1]; /* ACL_GROUP_OBJ */
acl2->a_entries[2] = acl->a_entries[1]; /* ACL_MASK */
acl2->a_entries[2].e_tag = ACL_MASK;
acl2->a_entries[3] = acl->a_entries[2]; /* ACL_OTHER */
nfsacl_desc.acl = acl2;
}
err = xdr_encode_array2(buf, base + 4, &nfsacl_desc.desc);
if (!err)
err = 8 + nfsacl_desc.desc.elem_size *
nfsacl_desc.desc.array_len;
return err;
}
struct nfsacl_decode_desc {
struct xdr_array2_desc desc;
unsigned int count;
struct posix_acl *acl;
};
static int
xdr_nfsace_decode(struct xdr_array2_desc *desc, void *elem)
{
struct nfsacl_decode_desc *nfsacl_desc =
(struct nfsacl_decode_desc *) desc;
__be32 *p = elem;
struct posix_acl_entry *entry;
unsigned int id;
if (!nfsacl_desc->acl) {
if (desc->array_len > NFS_ACL_MAX_ENTRIES)
return -EINVAL;
nfsacl_desc->acl = posix_acl_alloc(desc->array_len, GFP_KERNEL);
if (!nfsacl_desc->acl)
return -ENOMEM;
nfsacl_desc->count = 0;
}
entry = &nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
entry->e_tag = ntohl(*p++) & ~NFS_ACL_DEFAULT;
id = ntohl(*p++);
entry->e_perm = ntohl(*p++);
switch(entry->e_tag) {
case ACL_USER:
entry->e_uid = make_kuid(&init_user_ns, id);
if (!uid_valid(entry->e_uid))
return -EINVAL;
break;
case ACL_GROUP:
entry->e_gid = make_kgid(&init_user_ns, id);
if (!gid_valid(entry->e_gid))
return -EINVAL;
break;
case ACL_USER_OBJ:
case ACL_GROUP_OBJ:
case ACL_OTHER:
if (entry->e_perm & ~S_IRWXO)
return -EINVAL;
break;
case ACL_MASK:
/* Solaris sometimes sets additional bits in the mask */
entry->e_perm &= S_IRWXO;
break;
default:
return -EINVAL;
}
return 0;
}
static int
cmp_acl_entry(const void *x, const void *y)
{
const struct posix_acl_entry *a = x, *b = y;
if (a->e_tag != b->e_tag)
return a->e_tag - b->e_tag;
else if ((a->e_tag == ACL_USER) && uid_gt(a->e_uid, b->e_uid))
return 1;
else if ((a->e_tag == ACL_USER) && uid_lt(a->e_uid, b->e_uid))
return -1;
else if ((a->e_tag == ACL_GROUP) && gid_gt(a->e_gid, b->e_gid))
return 1;
else if ((a->e_tag == ACL_GROUP) && gid_lt(a->e_gid, b->e_gid))
return -1;
else
return 0;
}
/*
* Convert from a Solaris ACL to a POSIX 1003.1e draft 17 ACL.
*/
static int
posix_acl_from_nfsacl(struct posix_acl *acl)
{
struct posix_acl_entry *pa, *pe,
*group_obj = NULL, *mask = NULL;
if (!acl)
return 0;
sort(acl->a_entries, acl->a_count, sizeof(struct posix_acl_entry),
cmp_acl_entry, NULL);
/* Find the ACL_GROUP_OBJ and ACL_MASK entries. */
FOREACH_ACL_ENTRY(pa, acl, pe) {
switch(pa->e_tag) {
case ACL_USER_OBJ:
break;
case ACL_GROUP_OBJ:
group_obj = pa;
break;
case ACL_MASK:
mask = pa;
/* fall through */
case ACL_OTHER:
break;
}
}
if (acl->a_count == 4 && group_obj && mask &&
mask->e_perm == group_obj->e_perm) {
/* remove bogus ACL_MASK entry */
memmove(mask, mask+1, (3 - (mask - acl->a_entries)) *
sizeof(struct posix_acl_entry));
acl->a_count = 3;
}
return 0;
}
/**
* nfsacl_decode - Decode an NFSv3 ACL
*
* @buf: xdr_buf containing XDR'd ACL data to decode
* @base: byte offset in xdr_buf where XDR'd ACL begins
* @aclcnt: count of ACEs in decoded posix_acl
* @pacl: buffer in which to place decoded posix_acl
*
* Returns the length of the decoded ACL in bytes, or a negative errno value.
*/
int nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
struct posix_acl **pacl)
{
struct nfsacl_decode_desc nfsacl_desc = {
.desc = {
.elem_size = 12,
.xcode = pacl ? xdr_nfsace_decode : NULL,
},
};
u32 entries;
int err;
if (xdr_decode_word(buf, base, &entries) ||
entries > NFS_ACL_MAX_ENTRIES)
return -EINVAL;
nfsacl_desc.desc.array_maxlen = entries;
err = xdr_decode_array2(buf, base + 4, &nfsacl_desc.desc);
if (err)
return err;
if (pacl) {
if (entries != nfsacl_desc.desc.array_len ||
posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) {
posix_acl_release(nfsacl_desc.acl);
return -EINVAL;
}
*pacl = nfsacl_desc.acl;
}
if (aclcnt)
*aclcnt = entries;
return 8 + nfsacl_desc.desc.elem_size *
nfsacl_desc.desc.array_len;
}