Skip to content

G
git2
Commit 5b78dbdb by Edward Thomson Committed by Edward Thomson
Options

git_buf: decode base85 inputs

parent 3149ff6f
Showing with 149 additions and 20 deletions
src/buffer.c
......@@ -273,42 +273,51 @@ int git_buf_encode_base64(git_buf *buf, const char *data, size_t len)
return 0;
}
/* The inverse of base64_encode, offset by '+' == 43. */
/* The inverse of base64_encode */
static const int8_t base64_decode[] = {
62,
-1, -1, -1,
63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61,
-1, -1, -1, 0, -1, -1, -1,
0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
-1, -1, -1, -1, -1, -1,
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38,
39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, 62, -1, -1, -1, 63,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, -1, -1, -1, 0, -1, -1,
-1, 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14,
15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, -1, -1, -1, -1, -1,
-1, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40,
41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
};
#define BASE64_DECODE_VALUE(c) (((c) < 43 || (c) > 122) ? -1 : base64_decode[c - 43])
int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len)
{
size_t i;
int8_t a, b, c, d;
size_t orig_size = buf->size, new_size;
if (len % 4) {
giterr_set(GITERR_INVALID, "invalid base64 input");
return -1;
}
assert(len % 4 == 0);
GITERR_CHECK_ALLOC_ADD(&new_size, (len / 4 * 3), buf->size);
GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
ENSURE_SIZE(buf, new_size);
for (i = 0; i < len; i += 4) {
if ((a = BASE64_DECODE_VALUE(base64[i])) < 0 ||
(b = BASE64_DECODE_VALUE(base64[i+1])) < 0 ||
(c = BASE64_DECODE_VALUE(base64[i+2])) < 0 ||
(d = BASE64_DECODE_VALUE(base64[i+3])) < 0) {
if ((a = base64_decode[(unsigned char)base64[i]]) < 0 ||
(b = base64_decode[(unsigned char)base64[i+1]]) < 0 ||
(c = base64_decode[(unsigned char)base64[i+2]]) < 0 ||
(d = base64_decode[(unsigned char)base64[i+3]]) < 0) {
buf->size = orig_size;
buf->ptr[buf->size] = '\0';
giterr_set(GITERR_INVALID, "Invalid base64 input");
giterr_set(GITERR_INVALID, "invalid base64 input");
return -1;
}
......@@ -321,7 +330,7 @@ int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len)
return 0;
}
static const char b85str[] =
static const char base85_encode[] =
"0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz!#$%&()*+-;<=>?@^_`{|}~";
int git_buf_encode_base85(git_buf *buf, const char *data, size_t len)
......@@ -351,7 +360,7 @@ int git_buf_encode_base85(git_buf *buf, const char *data, size_t len)
int val = acc % 85;
acc /= 85;
b85[i] = b85str[val];
b85[i] = base85_encode[val];
}
for (i = 0; i < 5; i++)
......@@ -363,6 +372,88 @@ int git_buf_encode_base85(git_buf *buf, const char *data, size_t len)
return 0;
}
/* The inverse of base85_encode */
static const int8_t base85_decode[] = {
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, 63, -1, 64, 65, 66, 67, -1, 68, 69, 70, 71, -1, 72, -1, -1,
1, 2, 3, 4, 5, 6, 7, 8, 9, 10, -1, 73, 74, 75, 76, 77,
78, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25,
26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, -1, -1, -1, 79, 80,
81, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51,
52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 82, 83, 84, 85, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1
};
int git_buf_decode_base85(
git_buf *buf,
const char *base85,
size_t base85_len,
size_t output_len)
{
size_t orig_size = buf->size, new_size;
if (base85_len % 5 ||
output_len > base85_len * 4 / 5) {
giterr_set(GITERR_INVALID, "invalid base85 input");
return -1;
}
GITERR_CHECK_ALLOC_ADD(&new_size, output_len, buf->size);
GITERR_CHECK_ALLOC_ADD(&new_size, new_size, 1);
ENSURE_SIZE(buf, new_size);
while (output_len) {
unsigned acc = 0;
int de, cnt = 4;
unsigned char ch;
do {
ch = *base85++;
de = base85_decode[ch];
if (--de < 0)
goto on_error;
acc = acc * 85 + de;
} while (--cnt);
ch = *base85++;
de = base85_decode[ch];
if (--de < 0)
goto on_error;
/* Detect overflow. */
if (0xffffffff / 85 < acc ||
0xffffffff - de < (acc *= 85))
goto on_error;
acc += de;
cnt = (output_len < 4) ? output_len : 4;
output_len -= cnt;
do {
acc = (acc << 8) | (acc >> 24);
buf->ptr[buf->size++] = acc;
} while (--cnt);
}
buf->ptr[buf->size] = 0;
return 0;
on_error:
buf->size = orig_size;
buf->ptr[buf->size] = '\0';
giterr_set(GITERR_INVALID, "invalid base85 input");
return -1;
}
int git_buf_vprintf(git_buf *buf, const char *format, va_list ap)
{
size_t expected_size, new_size;
......
src/buffer.h
......@@ -185,6 +185,8 @@ int git_buf_decode_base64(git_buf *buf, const char *base64, size_t len);
/* Write data as "base85" encoded in buffer */
int git_buf_encode_base85(git_buf *buf, const char *data, size_t len);
/* Decode the given "base85" and write the result to the buffer */
int git_buf_decode_base85(git_buf *buf, const char *base64, size_t len, size_t output_len);
/*
* Insert, remove or replace a portion of the buffer.
......
tests/core/buffer.c
......@@ -813,6 +813,42 @@ void test_core_buffer__encode_base85(void)
git_buf_free(&buf);
}
void test_core_buffer__decode_base85(void)
{
git_buf buf = GIT_BUF_INIT;
cl_git_pass(git_buf_decode_base85(&buf, "bZBXF", 5, 4));
cl_assert_equal_sz(4, buf.size);
cl_assert_equal_s("this", buf.ptr);
git_buf_clear(&buf);
cl_git_pass(git_buf_decode_base85(&buf, "ba!tca&BaE", 10, 8));
cl_assert_equal_sz(8, buf.size);
cl_assert_equal_s("two rnds", buf.ptr);
git_buf_clear(&buf);
cl_git_pass(git_buf_decode_base85(&buf, "bZBXFAZc?TVqtS-AUHK3Wo~0{WMyOk", 30, 23));
cl_assert_equal_sz(23, buf.size);
cl_assert_equal_s("this is base 85 encoded", buf.ptr);
git_buf_clear(&buf);
git_buf_free(&buf);
}
void test_core_buffer__decode_base85_fails_gracefully(void)
{
git_buf buf = GIT_BUF_INIT;
git_buf_puts(&buf, "foobar");
cl_git_fail(git_buf_decode_base85(&buf, "invalid charsZZ", 15, 42));
cl_git_fail(git_buf_decode_base85(&buf, "invalidchars__ ", 15, 42));
cl_git_fail(git_buf_decode_base85(&buf, "overflowZZ~~~~~", 15, 42));
cl_git_fail(git_buf_decode_base85(&buf, "truncated", 9, 42));
cl_assert_equal_sz(6, buf.size);
cl_assert_equal_s("foobar", buf.ptr);
}
void test_core_buffer__classify_with_utf8(void)
{
char *data0 = "Simple text\n";
......
Markdown is supported
0% or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment