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authorDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2022-11-18 00:57:01 +0100
committerDavid Oberhollenzer <david.oberhollenzer@sigma-star.at>2022-11-18 00:58:13 +0100
commit844fdd42f03a633f1dbce5d90b2ecf44698cf8b0 (patch)
tree1255d42327bb297b12dfd4e7adfd81e3fbea6762
parentda6eadc840716eb29b0175f39b2790bba166db4a (diff)
Add a single, central base64 decoder
Similar to the hex blob decoder, we need this once for tar and once for the filemap xattr parser. Simply add a single, central implementation to libutil, with a simple unit test, and then use it in both libtar and gensquashfs. Signed-off-by: David Oberhollenzer <david.oberhollenzer@sigma-star.at>
-rw-r--r--bin/gensquashfs/filemap_xattr.c86
-rw-r--r--include/util/util.h3
-rw-r--r--lib/tar/pax_header.c62
-rw-r--r--lib/util/Makemodule.am1
-rw-r--r--lib/util/base64_decode.c103
-rw-r--r--tests/libutil/Makemodule.am5
-rw-r--r--tests/libutil/base64_decode.c74
7 files changed, 202 insertions, 132 deletions
diff --git a/bin/gensquashfs/filemap_xattr.c b/bin/gensquashfs/filemap_xattr.c
index 059ce81..0b73d36 100644
--- a/bin/gensquashfs/filemap_xattr.c
+++ b/bin/gensquashfs/filemap_xattr.c
@@ -11,25 +11,6 @@
#define NEW_FILE_START "# file: "
// Taken from attr-2.5.1/tools/setfattr.c
-static int
-base64_digit(char c) {
- if (c >= 'A' && c <= 'Z')
- return c - 'A';
- else if (c >= 'a' && c <= 'z')
- return 26 + c - 'a';
- else if (c >= '0' && c <= '9')
- return 52 + c - '0';
- else if (c == '+')
- return 62;
- else if (c == '/')
- return 63;
- else if (c == '=')
- return -2;
- else
- return -1;
-}
-
-// Taken from attr-2.5.1/tools/setfattr.c
static char *
decode(const char *value, size_t *size) {
char *decoded = NULL;
@@ -50,71 +31,20 @@ decode(const char *value, size_t *size) {
return NULL;
}
} else if (value[0] == '0' && (value[1] == 's' || value[1] == 'S')) {
- const char *v = value + 2, *end = value + *size;
- int d0, d1, d2, d3;
- char *d;
+ size_t input_len = *size - 2;
- decoded = realloc(decoded, *size / 4 * 3);
+ *size = (input_len / 4) * 3;
+
+ decoded = realloc(decoded, *size);
if (decoded == NULL) {
return NULL;
}
- d = decoded;
- for (;;) {
- while (v < end && isspace(*v))
- v++;
- if (v == end) {
- d0 = d1 = d2 = d3 = -2;
- break;
- }
- if (v + 4 > end) {
- bad_base64_encoding:
- free(decoded);
- fprintf(stderr, "bad input encoding\n");
- return NULL;
- }
- d0 = base64_digit(*v++);
- d1 = base64_digit(*v++);
- d2 = base64_digit(*v++);
- d3 = base64_digit(*v++);
- if (d0 < 0 || d1 < 0 || d2 < 0 || d3 < 0)
- break;
- *d++ = (char)((d0 << 2) | (d1 >> 4));
- *d++ = (char)((d1 << 4) | (d2 >> 2));
- *d++ = (char)((d2 << 6) | d3);
- }
- if (d0 == -2) {
- if (d1 != -2 || d2 != -2 || d3 != -2)
- goto bad_base64_encoding;
- goto base64_end;
- }
- if (d0 == -1 || d1 < 0 || d2 == -1 || d3 == -1)
- goto bad_base64_encoding;
- *d++ = (char)((d0 << 2) | (d1 >> 4));
- if (d2 != -2)
- *d++ = (char)((d1 << 4) | (d2 >> 2));
- else {
- if (d1 & 0x0F || d3 != -2)
- goto bad_base64_encoding;
- goto base64_end;
- }
- if (d3 != -2)
- *d++ = (char)((d2 << 6) | d3);
- else if (d2 & 0x03)
- goto bad_base64_encoding;
- base64_end:
- while (v < end && isspace(*v))
- v++;
- if (v + 4 <= end && *v == '=') {
- if (*++v != '=' || *++v != '=' || *++v != '=')
- goto bad_base64_encoding;
- v++;
+ if (base64_decode(value + 2, input_len, decoded, size)) {
+ free(decoded);
+ fprintf(stderr, "bad input encoding\n");
+ return NULL;
}
- while (v < end && isspace(*v))
- v++;
- if (v < end)
- goto bad_base64_encoding;
- *size = d - decoded;
} else {
const char *v = value, *end = value + *size;
char *d;
diff --git a/include/util/util.h b/include/util/util.h
index 787580c..cd32887 100644
--- a/include/util/util.h
+++ b/include/util/util.h
@@ -80,4 +80,7 @@ SQFS_INTERNAL int check_file_range_equal(sqfs_file_t *file, void *scratch,
SQFS_INTERNAL int hex_decode(const char *in, size_t in_sz,
sqfs_u8 *out, size_t out_sz);
+SQFS_INTERNAL int base64_decode(const char *in, size_t in_len,
+ sqfs_u8 *out, size_t *out_len);
+
#endif /* SQFS_UTIL_H */
diff --git a/lib/tar/pax_header.c b/lib/tar/pax_header.c
index cc2f2b0..b61aab6 100644
--- a/lib/tar/pax_header.c
+++ b/lib/tar/pax_header.c
@@ -11,56 +11,6 @@
#include <string.h>
#include <stdlib.h>
-static sqfs_u8 base64_convert(char in)
-{
- if (isupper(in))
- return in - 'A';
- if (islower(in))
- return in - 'a' + 26;
- if (isdigit(in))
- return in - '0' + 52;
- if (in == '+')
- return 62;
- if (in == '/' || in == '-')
- return 63;
- return 0;
-}
-
-static size_t base64_decode(sqfs_u8 *out, const char *in, size_t len)
-{
- sqfs_u8 *start = out;
-
- while (len > 0) {
- unsigned int diff = 0, value = 0;
-
- while (diff < 4 && len > 0) {
- if (*in == '=' || *in == '_' || *in == '\0') {
- len = 0;
- } else {
- value = (value << 6) | base64_convert(*(in++));
- --len;
- ++diff;
- }
- }
-
- if (diff < 2)
- break;
-
- value <<= 6 * (4 - diff);
-
- switch (diff) {
- case 4: out[2] = value & 0xff; /* fall-through */
- case 3: out[1] = (value >> 8) & 0xff; /* fall-through */
- default: out[0] = (value >> 16) & 0xff;
- }
-
- out += (diff * 3) / 4;
- }
-
- *out = '\0';
- return out - start;
-}
-
static int pax_read_decimal(const char *str, sqfs_u64 *out)
{
sqfs_u64 result = 0;
@@ -201,10 +151,16 @@ static int pax_xattr_schily(tar_header_decoded_t *out,
static int pax_xattr_libarchive(tar_header_decoded_t *out,
tar_xattr_t *xattr)
{
+ int ret;
+
+ ret = base64_decode((const char *)xattr->value, xattr->value_len,
+ xattr->value, &xattr->value_len);
+ if (ret)
+ return -1;
+
urldecode(xattr->key);
- xattr->value_len = base64_decode(xattr->value,
- (const char *)xattr->value,
- xattr->value_len);
+
+ xattr->value[xattr->value_len] = '\0';
xattr->next = out->xattr;
out->xattr = xattr;
return 0;
diff --git a/lib/util/Makemodule.am b/lib/util/Makemodule.am
index 4f1f0da..ec38b7a 100644
--- a/lib/util/Makemodule.am
+++ b/lib/util/Makemodule.am
@@ -15,6 +15,7 @@ libutil_a_SOURCES += lib/util/filename_sane.c
libutil_a_SOURCES += lib/util/source_date_epoch.c
libutil_a_SOURCES += lib/util/file_cmp.c
libutil_a_SOURCES += lib/util/hex_decode.c
+libutil_a_SOURCES += lib/util/base64_decode.c
libutil_a_CFLAGS = $(AM_CFLAGS)
libutil_a_CPPFLAGS = $(AM_CPPFLAGS)
diff --git a/lib/util/base64_decode.c b/lib/util/base64_decode.c
new file mode 100644
index 0000000..b1cf5b6
--- /dev/null
+++ b/lib/util/base64_decode.c
@@ -0,0 +1,103 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * base64_decode.c
+ *
+ * Copyright (C) 2022 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "util/util.h"
+#include "util/test.h"
+
+#include <ctype.h>
+
+static int base64_digit(int c)
+{
+ if (isupper(c))
+ return c - 'A';
+ if (islower(c))
+ return c - 'a' + 26;
+ if (isdigit(c))
+ return c - '0' + 52;
+ if (c == '+')
+ return 62;
+ if (c == '/' || c == '-')
+ return 63;
+ return -1;
+}
+
+int base64_decode(const char *in, size_t in_len, sqfs_u8 *out, size_t *out_len)
+{
+ int i1, i2, i3, i4;
+ size_t count = 0;
+
+ while (in_len >= 4) {
+ i1 = base64_digit(*(in++));
+ i2 = base64_digit(*(in++));
+ i3 = *(in++);
+ i4 = *(in++);
+ in_len -= 4;
+
+ if (i1 < 0 || i2 < 0 || count >= *out_len)
+ goto fail;
+
+ out[count++] = (i1 << 2) | (i2 >> 4);
+
+ if (i3 == '=' || i3 == '_') {
+ if ((i4 != '=' && i4 != '_') || in_len > 0)
+ goto fail;
+ break;
+ }
+
+ i3 = base64_digit(i3);
+ if (i3 < 0 || count >= *out_len)
+ goto fail;
+
+ out[count++] = ((i2 & 0x0F) << 4) | (i3 >> 2);
+
+ if (i4 == '=' || i4 == '_') {
+ if (in_len > 0)
+ goto fail;
+ break;
+ }
+
+ i4 = base64_digit(i4);
+ if (i4 < 0 || count >= *out_len)
+ goto fail;
+
+ out[count++] = ((i3 & 0x3) << 6) | i4;
+ }
+
+ /* libarchive has this bizarre bastardization of truncated base64 */
+ if (in_len > 0) {
+ if (in_len == 1)
+ goto fail;
+
+ i1 = base64_digit(*(in++));
+ i2 = base64_digit(*(in++));
+ in_len -= 2;
+
+ if (i1 < 0 || i2 < 0 || count >= *out_len)
+ goto fail;
+
+ out[count++] = (i1 << 2) | (i2 >> 4);
+
+ if (in_len > 0) {
+ i3 = *(in++);
+ --in_len;
+
+ if (i3 != '=' && i3 != '_') {
+ i3 = base64_digit(i3);
+ if (i3 < 0 || count >= *out_len)
+ goto fail;
+
+ out[count++] = ((i2 & 0x0F) << 4) | (i3 >> 2);
+ }
+ }
+ }
+
+ *out_len = count;
+ return 0;
+fail:
+ *out_len = 0;
+ return -1;
+}
diff --git a/tests/libutil/Makemodule.am b/tests/libutil/Makemodule.am
index 5a69de4..724af50 100644
--- a/tests/libutil/Makemodule.am
+++ b/tests/libutil/Makemodule.am
@@ -33,10 +33,13 @@ test_sdate_epoch_LDADD = libutil.a libcompat.a
test_hex_decode_SOURCES = tests/libutil/hex_decode.c
test_hex_decode_LDADD = libutil.a libcompat.a
+test_base64_decode_SOURCES = tests/libutil/base64_decode.c
+test_base64_decode_LDADD = libutil.a libcompat.a
+
LIBUTIL_TESTS = \
test_str_table test_rbtree test_xxhash test_threadpool test_ismemzero \
test_canonicalize_name test_filename_sane test_filename_sane_w32 \
- test_sdate_epoch test_hex_decode
+ test_sdate_epoch test_hex_decode test_base64_decode
check_PROGRAMS += $(LIBUTIL_TESTS)
TESTS += $(LIBUTIL_TESTS)
diff --git a/tests/libutil/base64_decode.c b/tests/libutil/base64_decode.c
new file mode 100644
index 0000000..8f22a86
--- /dev/null
+++ b/tests/libutil/base64_decode.c
@@ -0,0 +1,74 @@
+/* SPDX-License-Identifier: GPL-3.0-or-later */
+/*
+ * base64_decode.c
+ *
+ * Copyright (C) 2022 David Oberhollenzer <goliath@infraroot.at>
+ */
+#include "config.h"
+#include "util/util.h"
+#include "util/test.h"
+
+static const struct {
+ int result;
+ const char *in;
+ const char *out;
+} test_vec[] = {
+ { 0, "", "" },
+ { 0, "Zg", "f" },
+ { 0, "Zg==", "f" },
+ { 0, "Zm8=", "fo" },
+ { 0, "Zm9v", "foo" },
+ { 0, "Zm9vYg==", "foob" },
+ { 0, "Zm9vYmE=", "fooba" },
+ { 0, "Zm9vYmFy", "foobar" },
+ { 0, "TGV0J3MgYWxsIGxvdmUgTGFpbiEK", "Let's all love Lain!\n" },
+ { -1, "Zg==X", "XX" },
+};
+
+int main(int argc, char **argv)
+{
+ sqfs_u8 buffer[256];
+ size_t i, j;
+ (void)argc; (void)argv;
+
+ for (i = 0; i < sizeof(test_vec) / sizeof(test_vec[0]); ++i) {
+ const size_t in_len = strlen(test_vec[i].in);
+ const size_t out_len = strlen(test_vec[i].out);
+ size_t real_out;
+ int ret;
+
+ /* initialize the buffer */
+ for (j = 0; j < sizeof(buffer); ++j) {
+ buffer[j] = (j % 2) ? 0xAA : 0x55;
+ }
+
+ /* convert */
+ real_out = sizeof(buffer);
+ ret = base64_decode(test_vec[i].in, in_len, buffer, &real_out);
+
+ /* make sure pattern is un-touched after expected offset */
+ j = (in_len / 4) * 3;
+ if (in_len % 4)
+ j += 3;
+
+ for (; j < sizeof(buffer); ++j) {
+ TEST_ASSERT(buffer[j] == ((j % 2) ? 0xAA : 0x55));
+ }
+
+ /* check result */
+ if (test_vec[i].result == 0) {
+ TEST_ASSERT(ret == 0);
+ TEST_EQUAL_UI(real_out, out_len);
+ ret = memcmp(buffer, test_vec[i].out, out_len);
+ TEST_ASSERT(ret == 0);
+ } else {
+ TEST_ASSERT(ret != 0);
+ TEST_EQUAL_UI(real_out, 0);
+ }
+
+ fprintf(stderr, "CASE %lu OK\n", (unsigned long)i);
+ }
+
+ return EXIT_SUCCESS;
+}
+