ceph: aes crypto and base64 encode/decode helpers

Helpers to encrypt/decrypt AES and base64.

Signed-off-by: Yehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Sage Weil <sage@newdream.net>

1 files changed, 99 insertions, 0 deletions

diff --git a/fs/ceph/armor.c b/fs/ceph/armor.c
new file mode 100644
index 000000000000..67b2c030924b
--- /dev/null
+++ b/fs/ceph/armor.c
@@ -0,0 +1,99 @@
+
+#include <linux/errno.h>
+
+/*
+ * base64 encode/decode.
+ */
+
+const char *pem_key = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
+
+static int encode_bits(int c)
+{
+        return pem_key[c];
+}
+
+static int decode_bits(char c)
+{
+        if (c >= 'A' && c <= 'Z')
+                return c - 'A';
+        if (c >= 'a' && c <= 'z')
+                return c - 'a' + 26;
+        if (c >= '0' && c <= '9')
+                return c - '0' + 52;
+        if (c == '+')
+                return 62;
+        if (c == '/')
+                return 63;
+        if (c == '=')
+                return 0; /* just non-negative, please */
+        return -EINVAL;
+}
+
+int ceph_armor(char *dst, const char *src, const char *end)
+{
+        int olen = 0;
+        int line = 0;
+
+        while (src < end) {
+                unsigned char a, b, c;
+
+                a = *src++;
+                *dst++ = encode_bits(a >> 2);
+                if (src < end) {
+                        b = *src++;
+                        *dst++ = encode_bits(((a & 3) << 4) | (b >> 4));
+                        if (src < end) {
+                                c = *src++;
+                                *dst++ = encode_bits(((b & 15) << 2) |
+                                                     (c >> 6));
+                                *dst++ = encode_bits(c & 63);
+                        } else {
+                                *dst++ = encode_bits((b & 15) << 2);
+                                *dst++ = '=';
+                        }
+                } else {
+                        *dst++ = encode_bits(((a & 3) << 4));
+                        *dst++ = '=';
+                        *dst++ = '=';
+                }
+                olen += 4;
+                line += 4;
+                if (line == 64) {
+                        line = 0;
+                        *(dst++) = '\n';
+                        olen++;
+                }
+        }
+        return olen;
+}
+
+int ceph_unarmor(char *dst, const char *src, const char *end)
+{
+        int olen = 0;
+
+        while (src < end) {
+                int a, b, c, d;
+
+                if (src < end && src[0] == '\n')
+                        src++;
+                if (src + 4 > end)
+                        return -EINVAL;
+                a = decode_bits(src[0]);
+                b = decode_bits(src[1]);
+                c = decode_bits(src[2]);
+                d = decode_bits(src[3]);
+                if (a < 0 || b < 0 || c < 0 || d < 0)
+                        return -EINVAL;
+
+                *dst++ = (a << 2) | (b >> 4);
+                if (src[2] == '=')
+                        return olen + 1;
+                *dst++ = ((b & 15) << 4) | (c >> 2);
+                if (src[3] == '=')
+                        return olen + 2;
+                *dst++ = ((c & 3) << 6) | d;
+                olen += 3;
+                src += 4;
+        }
+        return olen;
+}