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-rw-r--r--lib/mpi/mpicoder.c211
1 files changed, 52 insertions, 159 deletions
diff --git a/lib/mpi/mpicoder.c b/lib/mpi/mpicoder.c
index 716802b774e..4cc6442733f 100644
--- a/lib/mpi/mpicoder.c
+++ b/lib/mpi/mpicoder.c
@@ -18,72 +18,64 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA
*/
+#include <linux/bitops.h>
+#include <asm-generic/bitops/count_zeros.h>
#include "mpi-internal.h"
-#define DIM(v) (sizeof(v)/sizeof((v)[0]))
#define MAX_EXTERN_MPI_BITS 16384
-static uint8_t asn[15] = /* Object ID is 1.3.14.3.2.26 */
-{ 0x30, 0x21, 0x30, 0x09, 0x06, 0x05, 0x2b, 0x0e, 0x03,
- 0x02, 0x1a, 0x05, 0x00, 0x04, 0x14
-};
-
-MPI do_encode_md(const void *sha_buffer, unsigned nbits)
+/**
+ * mpi_read_raw_data - Read a raw byte stream as a positive integer
+ * @xbuffer: The data to read
+ * @nbytes: The amount of data to read
+ */
+MPI mpi_read_raw_data(const void *xbuffer, size_t nbytes)
{
- int nframe = (nbits + 7) / 8;
- uint8_t *frame, *fr_pt;
- int i = 0, n;
- size_t asnlen = DIM(asn);
- MPI a = MPI_NULL;
-
- if (SHA1_DIGEST_LENGTH + asnlen + 4 > nframe)
- pr_info("MPI: can't encode a %d bit MD into a %d bits frame\n",
- (int)(SHA1_DIGEST_LENGTH * 8), (int)nbits);
-
- /* We encode the MD in this way:
- *
- * 0 A PAD(n bytes) 0 ASN(asnlen bytes) MD(len bytes)
- *
- * PAD consists of FF bytes.
- */
- frame = kmalloc(nframe, GFP_KERNEL);
- if (!frame)
- return MPI_NULL;
- n = 0;
- frame[n++] = 0;
- frame[n++] = 1; /* block type */
- i = nframe - SHA1_DIGEST_LENGTH - asnlen - 3;
+ const uint8_t *buffer = xbuffer;
+ int i, j;
+ unsigned nbits, nlimbs;
+ mpi_limb_t a;
+ MPI val = NULL;
- if (i <= 1) {
- pr_info("MPI: message digest encoding failed\n");
- kfree(frame);
- return a;
+ while (nbytes > 0 && buffer[0] == 0) {
+ buffer++;
+ nbytes--;
}
- memset(frame + n, 0xff, i);
- n += i;
- frame[n++] = 0;
- memcpy(frame + n, &asn, asnlen);
- n += asnlen;
- memcpy(frame + n, sha_buffer, SHA1_DIGEST_LENGTH);
- n += SHA1_DIGEST_LENGTH;
-
- i = nframe;
- fr_pt = frame;
-
- if (n != nframe) {
- printk
- ("MPI: message digest encoding failed, frame length is wrong\n");
- kfree(frame);
- return a;
+ nbits = nbytes * 8;
+ if (nbits > MAX_EXTERN_MPI_BITS) {
+ pr_info("MPI: mpi too large (%u bits)\n", nbits);
+ return NULL;
}
+ if (nbytes > 0)
+ nbits -= count_leading_zeros(buffer[0]);
+ else
+ nbits = 0;
- a = mpi_alloc((nframe + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB);
- mpi_set_buffer(a, frame, nframe, 0);
- kfree(frame);
-
- return a;
+ nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
+ val = mpi_alloc(nlimbs);
+ if (!val)
+ return NULL;
+ val->nbits = nbits;
+ val->sign = 0;
+ val->nlimbs = nlimbs;
+
+ if (nbytes > 0) {
+ i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
+ i %= BYTES_PER_MPI_LIMB;
+ for (j = nlimbs; j > 0; j--) {
+ a = 0;
+ for (; i < BYTES_PER_MPI_LIMB; i++) {
+ a <<= 8;
+ a |= *buffer++;
+ }
+ i = 0;
+ val->d[j - 1] = a;
+ }
+ }
+ return val;
}
+EXPORT_SYMBOL_GPL(mpi_read_raw_data);
MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
{
@@ -91,7 +83,7 @@ MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
int i, j;
unsigned nbits, nbytes, nlimbs, nread = 0;
mpi_limb_t a;
- MPI val = MPI_NULL;
+ MPI val = NULL;
if (*ret_nread < 2)
goto leave;
@@ -104,11 +96,11 @@ MPI mpi_read_from_buffer(const void *xbuffer, unsigned *ret_nread)
buffer += 2;
nread = 2;
- nbytes = (nbits + 7) / 8;
- nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
+ nbytes = DIV_ROUND_UP(nbits, 8);
+ nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
val = mpi_alloc(nlimbs);
if (!val)
- return MPI_NULL;
+ return NULL;
i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
i %= BYTES_PER_MPI_LIMB;
val->nbits = nbits;
@@ -137,105 +129,6 @@ leave:
EXPORT_SYMBOL_GPL(mpi_read_from_buffer);
/****************
- * Make an mpi from a character string.
- */
-int mpi_fromstr(MPI val, const char *str)
-{
- int hexmode = 0, sign = 0, prepend_zero = 0, i, j, c, c1, c2;
- unsigned nbits, nbytes, nlimbs;
- mpi_limb_t a;
-
- if (*str == '-') {
- sign = 1;
- str++;
- }
- if (*str == '0' && str[1] == 'x')
- hexmode = 1;
- else
- return -EINVAL; /* other bases are not yet supported */
- str += 2;
-
- nbits = strlen(str) * 4;
- if (nbits % 8)
- prepend_zero = 1;
- nbytes = (nbits + 7) / 8;
- nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
- if (val->alloced < nlimbs)
- if (!mpi_resize(val, nlimbs))
- return -ENOMEM;
- i = BYTES_PER_MPI_LIMB - nbytes % BYTES_PER_MPI_LIMB;
- i %= BYTES_PER_MPI_LIMB;
- j = val->nlimbs = nlimbs;
- val->sign = sign;
- for (; j > 0; j--) {
- a = 0;
- for (; i < BYTES_PER_MPI_LIMB; i++) {
- if (prepend_zero) {
- c1 = '0';
- prepend_zero = 0;
- } else
- c1 = *str++;
- assert(c1);
- c2 = *str++;
- assert(c2);
- if (c1 >= '0' && c1 <= '9')
- c = c1 - '0';
- else if (c1 >= 'a' && c1 <= 'f')
- c = c1 - 'a' + 10;
- else if (c1 >= 'A' && c1 <= 'F')
- c = c1 - 'A' + 10;
- else {
- mpi_clear(val);
- return 1;
- }
- c <<= 4;
- if (c2 >= '0' && c2 <= '9')
- c |= c2 - '0';
- else if (c2 >= 'a' && c2 <= 'f')
- c |= c2 - 'a' + 10;
- else if (c2 >= 'A' && c2 <= 'F')
- c |= c2 - 'A' + 10;
- else {
- mpi_clear(val);
- return 1;
- }
- a <<= 8;
- a |= c;
- }
- i = 0;
-
- val->d[j - 1] = a;
- }
-
- return 0;
-}
-EXPORT_SYMBOL_GPL(mpi_fromstr);
-
-/****************
- * Special function to get the low 8 bytes from an mpi.
- * This can be used as a keyid; KEYID is an 2 element array.
- * Return the low 4 bytes.
- */
-u32 mpi_get_keyid(const MPI a, u32 *keyid)
-{
-#if BYTES_PER_MPI_LIMB == 4
- if (keyid) {
- keyid[0] = a->nlimbs >= 2 ? a->d[1] : 0;
- keyid[1] = a->nlimbs >= 1 ? a->d[0] : 0;
- }
- return a->nlimbs >= 1 ? a->d[0] : 0;
-#elif BYTES_PER_MPI_LIMB == 8
- if (keyid) {
- keyid[0] = a->nlimbs ? (u32) (a->d[0] >> 32) : 0;
- keyid[1] = a->nlimbs ? (u32) (a->d[0] & 0xffffffff) : 0;
- }
- return a->nlimbs ? (u32) (a->d[0] & 0xffffffff) : 0;
-#else
-#error Make this function work with other LIMB sizes
-#endif
-}
-
-/****************
* Return an allocated buffer with the MPI (msb first).
* NBYTES receives the length of this buffer. Caller must free the
* return string (This function does return a 0 byte buffer with NBYTES
@@ -300,7 +193,7 @@ int mpi_set_buffer(MPI a, const void *xbuffer, unsigned nbytes, int sign)
int nlimbs;
int i;
- nlimbs = (nbytes + BYTES_PER_MPI_LIMB - 1) / BYTES_PER_MPI_LIMB;
+ nlimbs = DIV_ROUND_UP(nbytes, BYTES_PER_MPI_LIMB);
if (RESIZE_IF_NEEDED(a, nlimbs) < 0)
return -ENOMEM;
a->sign = sign;
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