~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/fs/nfs_common/nfsacl.c

Version: ~ [ linux-5.6 ] ~ [ linux-5.5.13 ] ~ [ linux-5.4.28 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.113 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.174 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.217 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.217 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.82 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * fs/nfs_common/nfsacl.c
  3  *
  4  *  Copyright (C) 2002-2003 Andreas Gruenbacher <agruen@suse.de>
  5  */
  6 
  7 /*
  8  * The Solaris nfsacl protocol represents some ACLs slightly differently
  9  * than POSIX 1003.1e draft 17 does (and we do):
 10  *
 11  *  - Minimal ACLs always have an ACL_MASK entry, so they have
 12  *    four instead of three entries.
 13  *  - The ACL_MASK entry in such minimal ACLs always has the same
 14  *    permissions as the ACL_GROUP_OBJ entry. (In extended ACLs
 15  *    the ACL_MASK and ACL_GROUP_OBJ entries may differ.)
 16  *  - The identifier fields of the ACL_USER_OBJ and ACL_GROUP_OBJ
 17  *    entries contain the identifiers of the owner and owning group.
 18  *    (In POSIX ACLs we always set them to ACL_UNDEFINED_ID).
 19  *  - ACL entries in the kernel are kept sorted in ascending order
 20  *    of (e_tag, e_id). Solaris ACLs are unsorted.
 21  */
 22 
 23 #include <linux/module.h>
 24 #include <linux/fs.h>
 25 #include <linux/gfp.h>
 26 #include <linux/sunrpc/xdr.h>
 27 #include <linux/nfsacl.h>
 28 #include <linux/nfs3.h>
 29 #include <linux/sort.h>
 30 
 31 MODULE_LICENSE("GPL");
 32 
 33 EXPORT_SYMBOL_GPL(nfsacl_encode);
 34 EXPORT_SYMBOL_GPL(nfsacl_decode);
 35 
 36 struct nfsacl_encode_desc {
 37         struct xdr_array2_desc desc;
 38         unsigned int count;
 39         struct posix_acl *acl;
 40         int typeflag;
 41         uid_t uid;
 42         gid_t gid;
 43 };
 44 
 45 struct nfsacl_simple_acl {
 46         struct posix_acl acl;
 47         struct posix_acl_entry ace[4];
 48 };
 49 
 50 static int
 51 xdr_nfsace_encode(struct xdr_array2_desc *desc, void *elem)
 52 {
 53         struct nfsacl_encode_desc *nfsacl_desc =
 54                 (struct nfsacl_encode_desc *) desc;
 55         __be32 *p = elem;
 56 
 57         struct posix_acl_entry *entry =
 58                 &nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
 59 
 60         *p++ = htonl(entry->e_tag | nfsacl_desc->typeflag);
 61         switch(entry->e_tag) {
 62                 case ACL_USER_OBJ:
 63                         *p++ = htonl(nfsacl_desc->uid);
 64                         break;
 65                 case ACL_GROUP_OBJ:
 66                         *p++ = htonl(nfsacl_desc->gid);
 67                         break;
 68                 case ACL_USER:
 69                 case ACL_GROUP:
 70                         *p++ = htonl(entry->e_id);
 71                         break;
 72                 default:  /* Solaris depends on that! */
 73                         *p++ = 0;
 74                         break;
 75         }
 76         *p++ = htonl(entry->e_perm & S_IRWXO);
 77         return 0;
 78 }
 79 
 80 /**
 81  * nfsacl_encode - Encode an NFSv3 ACL
 82  *
 83  * @buf: destination xdr_buf to contain XDR encoded ACL
 84  * @base: byte offset in xdr_buf where XDR'd ACL begins
 85  * @inode: inode of file whose ACL this is
 86  * @acl: posix_acl to encode
 87  * @encode_entries: whether to encode ACEs as well
 88  * @typeflag: ACL type: NFS_ACL_DEFAULT or zero
 89  *
 90  * Returns size of encoded ACL in bytes or a negative errno value.
 91  */
 92 int nfsacl_encode(struct xdr_buf *buf, unsigned int base, struct inode *inode,
 93                   struct posix_acl *acl, int encode_entries, int typeflag)
 94 {
 95         int entries = (acl && acl->a_count) ? max_t(int, acl->a_count, 4) : 0;
 96         struct nfsacl_encode_desc nfsacl_desc = {
 97                 .desc = {
 98                         .elem_size = 12,
 99                         .array_len = encode_entries ? entries : 0,
100                         .xcode = xdr_nfsace_encode,
101                 },
102                 .acl = acl,
103                 .typeflag = typeflag,
104                 .uid = inode->i_uid,
105                 .gid = inode->i_gid,
106         };
107         struct nfsacl_simple_acl aclbuf;
108         int err;
109 
110         if (entries > NFS_ACL_MAX_ENTRIES ||
111             xdr_encode_word(buf, base, entries))
112                 return -EINVAL;
113         if (encode_entries && acl && acl->a_count == 3) {
114                 struct posix_acl *acl2 = &aclbuf.acl;
115 
116                 /* Avoid the use of posix_acl_alloc().  nfsacl_encode() is
117                  * invoked in contexts where a memory allocation failure is
118                  * fatal.  Fortunately this fake ACL is small enough to
119                  * construct on the stack. */
120                 posix_acl_init(acl2, 4);
121 
122                 /* Insert entries in canonical order: other orders seem
123                  to confuse Solaris VxFS. */
124                 acl2->a_entries[0] = acl->a_entries[0];  /* ACL_USER_OBJ */
125                 acl2->a_entries[1] = acl->a_entries[1];  /* ACL_GROUP_OBJ */
126                 acl2->a_entries[2] = acl->a_entries[1];  /* ACL_MASK */
127                 acl2->a_entries[2].e_tag = ACL_MASK;
128                 acl2->a_entries[3] = acl->a_entries[2];  /* ACL_OTHER */
129                 nfsacl_desc.acl = acl2;
130         }
131         err = xdr_encode_array2(buf, base + 4, &nfsacl_desc.desc);
132         if (!err)
133                 err = 8 + nfsacl_desc.desc.elem_size *
134                           nfsacl_desc.desc.array_len;
135         return err;
136 }
137 
138 struct nfsacl_decode_desc {
139         struct xdr_array2_desc desc;
140         unsigned int count;
141         struct posix_acl *acl;
142 };
143 
144 static int
145 xdr_nfsace_decode(struct xdr_array2_desc *desc, void *elem)
146 {
147         struct nfsacl_decode_desc *nfsacl_desc =
148                 (struct nfsacl_decode_desc *) desc;
149         __be32 *p = elem;
150         struct posix_acl_entry *entry;
151 
152         if (!nfsacl_desc->acl) {
153                 if (desc->array_len > NFS_ACL_MAX_ENTRIES)
154                         return -EINVAL;
155                 nfsacl_desc->acl = posix_acl_alloc(desc->array_len, GFP_KERNEL);
156                 if (!nfsacl_desc->acl)
157                         return -ENOMEM;
158                 nfsacl_desc->count = 0;
159         }
160 
161         entry = &nfsacl_desc->acl->a_entries[nfsacl_desc->count++];
162         entry->e_tag = ntohl(*p++) & ~NFS_ACL_DEFAULT;
163         entry->e_id = ntohl(*p++);
164         entry->e_perm = ntohl(*p++);
165 
166         switch(entry->e_tag) {
167                 case ACL_USER_OBJ:
168                 case ACL_USER:
169                 case ACL_GROUP_OBJ:
170                 case ACL_GROUP:
171                 case ACL_OTHER:
172                         if (entry->e_perm & ~S_IRWXO)
173                                 return -EINVAL;
174                         break;
175                 case ACL_MASK:
176                         /* Solaris sometimes sets additional bits in the mask */
177                         entry->e_perm &= S_IRWXO;
178                         break;
179                 default:
180                         return -EINVAL;
181         }
182 
183         return 0;
184 }
185 
186 static int
187 cmp_acl_entry(const void *x, const void *y)
188 {
189         const struct posix_acl_entry *a = x, *b = y;
190 
191         if (a->e_tag != b->e_tag)
192                 return a->e_tag - b->e_tag;
193         else if (a->e_id > b->e_id)
194                 return 1;
195         else if (a->e_id < b->e_id)
196                 return -1;
197         else
198                 return 0;
199 }
200 
201 /*
202  * Convert from a Solaris ACL to a POSIX 1003.1e draft 17 ACL.
203  */
204 static int
205 posix_acl_from_nfsacl(struct posix_acl *acl)
206 {
207         struct posix_acl_entry *pa, *pe,
208                *group_obj = NULL, *mask = NULL;
209 
210         if (!acl)
211                 return 0;
212 
213         sort(acl->a_entries, acl->a_count, sizeof(struct posix_acl_entry),
214              cmp_acl_entry, NULL);
215 
216         /* Clear undefined identifier fields and find the ACL_GROUP_OBJ
217            and ACL_MASK entries. */
218         FOREACH_ACL_ENTRY(pa, acl, pe) {
219                 switch(pa->e_tag) {
220                         case ACL_USER_OBJ:
221                                 pa->e_id = ACL_UNDEFINED_ID;
222                                 break;
223                         case ACL_GROUP_OBJ:
224                                 pa->e_id = ACL_UNDEFINED_ID;
225                                 group_obj = pa;
226                                 break;
227                         case ACL_MASK:
228                                 mask = pa;
229                                 /* fall through */
230                         case ACL_OTHER:
231                                 pa->e_id = ACL_UNDEFINED_ID;
232                                 break;
233                 }
234         }
235         if (acl->a_count == 4 && group_obj && mask &&
236             mask->e_perm == group_obj->e_perm) {
237                 /* remove bogus ACL_MASK entry */
238                 memmove(mask, mask+1, (3 - (mask - acl->a_entries)) *
239                                       sizeof(struct posix_acl_entry));
240                 acl->a_count = 3;
241         }
242         return 0;
243 }
244 
245 /**
246  * nfsacl_decode - Decode an NFSv3 ACL
247  *
248  * @buf: xdr_buf containing XDR'd ACL data to decode
249  * @base: byte offset in xdr_buf where XDR'd ACL begins
250  * @aclcnt: count of ACEs in decoded posix_acl
251  * @pacl: buffer in which to place decoded posix_acl
252  *
253  * Returns the length of the decoded ACL in bytes, or a negative errno value.
254  */
255 int nfsacl_decode(struct xdr_buf *buf, unsigned int base, unsigned int *aclcnt,
256                   struct posix_acl **pacl)
257 {
258         struct nfsacl_decode_desc nfsacl_desc = {
259                 .desc = {
260                         .elem_size = 12,
261                         .xcode = pacl ? xdr_nfsace_decode : NULL,
262                 },
263         };
264         u32 entries;
265         int err;
266 
267         if (xdr_decode_word(buf, base, &entries) ||
268             entries > NFS_ACL_MAX_ENTRIES)
269                 return -EINVAL;
270         nfsacl_desc.desc.array_maxlen = entries;
271         err = xdr_decode_array2(buf, base + 4, &nfsacl_desc.desc);
272         if (err)
273                 return err;
274         if (pacl) {
275                 if (entries != nfsacl_desc.desc.array_len ||
276                     posix_acl_from_nfsacl(nfsacl_desc.acl) != 0) {
277                         posix_acl_release(nfsacl_desc.acl);
278                         return -EINVAL;
279                 }
280                 *pacl = nfsacl_desc.acl;
281         }
282         if (aclcnt)
283                 *aclcnt = entries;
284         return 8 + nfsacl_desc.desc.elem_size *
285                    nfsacl_desc.desc.array_len;
286 }
287 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp