diff options
Diffstat (limited to 'security/selinux/ss/ebitmap.c')
| -rw-r--r-- | security/selinux/ss/ebitmap.c | 140 |
1 files changed, 140 insertions, 0 deletions
diff --git a/security/selinux/ss/ebitmap.c b/security/selinux/ss/ebitmap.c index 47024a6e184..cfed1d30fa6 100644 --- a/security/selinux/ss/ebitmap.c +++ b/security/selinux/ss/ebitmap.c @@ -3,6 +3,14 @@ * * Author : Stephen Smalley, <sds@epoch.ncsc.mil> */ +/* + * Updated: Hewlett-Packard <paul.moore@hp.com> + * + * Added ebitmap_export() and ebitmap_import() + * + * (c) Copyright Hewlett-Packard Development Company, L.P., 2006 + */ + #include <linux/kernel.h> #include <linux/slab.h> #include <linux/errno.h> @@ -59,6 +67,138 @@ int ebitmap_cpy(struct ebitmap *dst, struct ebitmap *src) return 0; } +/** + * ebitmap_export - Export an ebitmap to a unsigned char bitmap string + * @src: the ebitmap to export + * @dst: the resulting bitmap string + * @dst_len: length of dst in bytes + * + * Description: + * Allocate a buffer at least src->highbit bits long and export the extensible + * bitmap into the buffer. The bitmap string will be in little endian format, + * i.e. LSB first. The value returned in dst_len may not the true size of the + * buffer as the length of the buffer is rounded up to a multiple of MAPTYPE. + * The caller must free the buffer when finished. Returns zero on success, + * negative values on failure. + * + */ +int ebitmap_export(const struct ebitmap *src, + unsigned char **dst, + size_t *dst_len) +{ + size_t bitmap_len; + unsigned char *bitmap; + struct ebitmap_node *iter_node; + MAPTYPE node_val; + size_t bitmap_byte; + unsigned char bitmask; + + bitmap_len = src->highbit / 8; + if (src->highbit % 7) + bitmap_len += 1; + if (bitmap_len == 0) + return -EINVAL; + + bitmap = kzalloc((bitmap_len & ~(sizeof(MAPTYPE) - 1)) + + sizeof(MAPTYPE), + GFP_ATOMIC); + if (bitmap == NULL) + return -ENOMEM; + + iter_node = src->node; + do { + bitmap_byte = iter_node->startbit / 8; + bitmask = 0x80; + node_val = iter_node->map; + do { + if (bitmask == 0) { + bitmap_byte++; + bitmask = 0x80; + } + if (node_val & (MAPTYPE)0x01) + bitmap[bitmap_byte] |= bitmask; + node_val >>= 1; + bitmask >>= 1; + } while (node_val > 0); + iter_node = iter_node->next; + } while (iter_node); + + *dst = bitmap; + *dst_len = bitmap_len; + return 0; +} + +/** + * ebitmap_import - Import an unsigned char bitmap string into an ebitmap + * @src: the bitmap string + * @src_len: the bitmap length in bytes + * @dst: the empty ebitmap + * + * Description: + * This function takes a little endian bitmap string in src and imports it into + * the ebitmap pointed to by dst. Returns zero on success, negative values on + * failure. + * + */ +int ebitmap_import(const unsigned char *src, + size_t src_len, + struct ebitmap *dst) +{ + size_t src_off = 0; + size_t node_limit; + struct ebitmap_node *node_new; + struct ebitmap_node *node_last = NULL; + u32 i_byte; + u32 i_bit; + unsigned char src_byte; + + while (src_off < src_len) { + if (src_len - src_off >= sizeof(MAPTYPE)) { + if (*(MAPTYPE *)&src[src_off] == 0) { + src_off += sizeof(MAPTYPE); + continue; + } + node_limit = sizeof(MAPTYPE); + } else { + for (src_byte = 0, i_byte = src_off; + i_byte < src_len && src_byte == 0; + i_byte++) + src_byte |= src[i_byte]; + if (src_byte == 0) + break; + node_limit = src_len - src_off; + } + + node_new = kzalloc(sizeof(*node_new), GFP_ATOMIC); + if (unlikely(node_new == NULL)) { + ebitmap_destroy(dst); + return -ENOMEM; + } + node_new->startbit = src_off * 8; + for (i_byte = 0; i_byte < node_limit; i_byte++) { + src_byte = src[src_off++]; + for (i_bit = i_byte * 8; src_byte != 0; i_bit++) { + if (src_byte & 0x80) + node_new->map |= MAPBIT << i_bit; + src_byte <<= 1; + } + } + + if (node_last != NULL) + node_last->next = node_new; + else + dst->node = node_new; + node_last = node_new; + } + + if (likely(node_last != NULL)) + dst->highbit = node_last->startbit + MAPSIZE; + else + ebitmap_init(dst); + + return 0; +} + int ebitmap_contains(struct ebitmap *e1, struct ebitmap *e2) { struct ebitmap_node *n1, *n2; |