summaryrefslogtreecommitdiffstats
path: root/lib/hexdump.c
diff options
context:
space:
mode:
Diffstat (limited to 'lib/hexdump.c')
-rw-r--r--lib/hexdump.c295
1 files changed, 295 insertions, 0 deletions
diff --git a/lib/hexdump.c b/lib/hexdump.c
new file mode 100644
index 0000000000..06833d4043
--- /dev/null
+++ b/lib/hexdump.c
@@ -0,0 +1,295 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * lib/hexdump.c
+ */
+
+#include <linux/types.h>
+#include <linux/ctype.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/minmax.h>
+#include <linux/export.h>
+#include <asm/unaligned.h>
+
+const char hex_asc[] = "0123456789abcdef";
+EXPORT_SYMBOL(hex_asc);
+const char hex_asc_upper[] = "0123456789ABCDEF";
+EXPORT_SYMBOL(hex_asc_upper);
+
+/**
+ * hex_to_bin - convert a hex digit to its real value
+ * @ch: ascii character represents hex digit
+ *
+ * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad
+ * input.
+ *
+ * This function is used to load cryptographic keys, so it is coded in such a
+ * way that there are no conditions or memory accesses that depend on data.
+ *
+ * Explanation of the logic:
+ * (ch - '9' - 1) is negative if ch <= '9'
+ * ('0' - 1 - ch) is negative if ch >= '0'
+ * we "and" these two values, so the result is negative if ch is in the range
+ * '0' ... '9'
+ * we are only interested in the sign, so we do a shift ">> 8"; note that right
+ * shift of a negative value is implementation-defined, so we cast the
+ * value to (unsigned) before the shift --- we have 0xffffff if ch is in
+ * the range '0' ... '9', 0 otherwise
+ * we "and" this value with (ch - '0' + 1) --- we have a value 1 ... 10 if ch is
+ * in the range '0' ... '9', 0 otherwise
+ * we add this value to -1 --- we have a value 0 ... 9 if ch is in the range '0'
+ * ... '9', -1 otherwise
+ * the next line is similar to the previous one, but we need to decode both
+ * uppercase and lowercase letters, so we use (ch & 0xdf), which converts
+ * lowercase to uppercase
+ */
+int hex_to_bin(unsigned char ch)
+{
+ unsigned char cu = ch & 0xdf;
+ return -1 +
+ ((ch - '0' + 1) & (unsigned)((ch - '9' - 1) & ('0' - 1 - ch)) >> 8) +
+ ((cu - 'A' + 11) & (unsigned)((cu - 'F' - 1) & ('A' - 1 - cu)) >> 8);
+}
+EXPORT_SYMBOL(hex_to_bin);
+
+/**
+ * hex2bin - convert an ascii hexadecimal string to its binary representation
+ * @dst: binary result
+ * @src: ascii hexadecimal string
+ * @count: result length
+ *
+ * Return 0 on success, -EINVAL in case of bad input.
+ */
+int hex2bin(u8 *dst, const char *src, size_t count)
+{
+ while (count--) {
+ int hi, lo;
+
+ hi = hex_to_bin(*src++);
+ if (unlikely(hi < 0))
+ return -EINVAL;
+ lo = hex_to_bin(*src++);
+ if (unlikely(lo < 0))
+ return -EINVAL;
+
+ *dst++ = (hi << 4) | lo;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(hex2bin);
+
+/**
+ * bin2hex - convert binary data to an ascii hexadecimal string
+ * @dst: ascii hexadecimal result
+ * @src: binary data
+ * @count: binary data length
+ */
+char *bin2hex(char *dst, const void *src, size_t count)
+{
+ const unsigned char *_src = src;
+
+ while (count--)
+ dst = hex_byte_pack(dst, *_src++);
+ return dst;
+}
+EXPORT_SYMBOL(bin2hex);
+
+/**
+ * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory
+ * @buf: data blob to dump
+ * @len: number of bytes in the @buf
+ * @rowsize: number of bytes to print per line; must be 16 or 32
+ * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
+ * @linebuf: where to put the converted data
+ * @linebuflen: total size of @linebuf, including space for terminating NUL
+ * @ascii: include ASCII after the hex output
+ *
+ * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,
+ * 16 or 32 bytes of input data converted to hex + ASCII output.
+ *
+ * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data
+ * to a hex + ASCII dump at the supplied memory location.
+ * The converted output is always NUL-terminated.
+ *
+ * E.g.:
+ * hex_dump_to_buffer(frame->data, frame->len, 16, 1,
+ * linebuf, sizeof(linebuf), true);
+ *
+ * example output buffer:
+ * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
+ *
+ * Return:
+ * The amount of bytes placed in the buffer without terminating NUL. If the
+ * output was truncated, then the return value is the number of bytes
+ * (excluding the terminating NUL) which would have been written to the final
+ * string if enough space had been available.
+ */
+int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,
+ char *linebuf, size_t linebuflen, bool ascii)
+{
+ const u8 *ptr = buf;
+ int ngroups;
+ u8 ch;
+ int j, lx = 0;
+ int ascii_column;
+ int ret;
+
+ if (rowsize != 16 && rowsize != 32)
+ rowsize = 16;
+
+ if (len > rowsize) /* limit to one line at a time */
+ len = rowsize;
+ if (!is_power_of_2(groupsize) || groupsize > 8)
+ groupsize = 1;
+ if ((len % groupsize) != 0) /* no mixed size output */
+ groupsize = 1;
+
+ ngroups = len / groupsize;
+ ascii_column = rowsize * 2 + rowsize / groupsize + 1;
+
+ if (!linebuflen)
+ goto overflow1;
+
+ if (!len)
+ goto nil;
+
+ if (groupsize == 8) {
+ const u64 *ptr8 = buf;
+
+ for (j = 0; j < ngroups; j++) {
+ ret = snprintf(linebuf + lx, linebuflen - lx,
+ "%s%16.16llx", j ? " " : "",
+ get_unaligned(ptr8 + j));
+ if (ret >= linebuflen - lx)
+ goto overflow1;
+ lx += ret;
+ }
+ } else if (groupsize == 4) {
+ const u32 *ptr4 = buf;
+
+ for (j = 0; j < ngroups; j++) {
+ ret = snprintf(linebuf + lx, linebuflen - lx,
+ "%s%8.8x", j ? " " : "",
+ get_unaligned(ptr4 + j));
+ if (ret >= linebuflen - lx)
+ goto overflow1;
+ lx += ret;
+ }
+ } else if (groupsize == 2) {
+ const u16 *ptr2 = buf;
+
+ for (j = 0; j < ngroups; j++) {
+ ret = snprintf(linebuf + lx, linebuflen - lx,
+ "%s%4.4x", j ? " " : "",
+ get_unaligned(ptr2 + j));
+ if (ret >= linebuflen - lx)
+ goto overflow1;
+ lx += ret;
+ }
+ } else {
+ for (j = 0; j < len; j++) {
+ if (linebuflen < lx + 2)
+ goto overflow2;
+ ch = ptr[j];
+ linebuf[lx++] = hex_asc_hi(ch);
+ if (linebuflen < lx + 2)
+ goto overflow2;
+ linebuf[lx++] = hex_asc_lo(ch);
+ if (linebuflen < lx + 2)
+ goto overflow2;
+ linebuf[lx++] = ' ';
+ }
+ if (j)
+ lx--;
+ }
+ if (!ascii)
+ goto nil;
+
+ while (lx < ascii_column) {
+ if (linebuflen < lx + 2)
+ goto overflow2;
+ linebuf[lx++] = ' ';
+ }
+ for (j = 0; j < len; j++) {
+ if (linebuflen < lx + 2)
+ goto overflow2;
+ ch = ptr[j];
+ linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';
+ }
+nil:
+ linebuf[lx] = '\0';
+ return lx;
+overflow2:
+ linebuf[lx++] = '\0';
+overflow1:
+ return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;
+}
+EXPORT_SYMBOL(hex_dump_to_buffer);
+
+#ifdef CONFIG_PRINTK
+/**
+ * print_hex_dump - print a text hex dump to syslog for a binary blob of data
+ * @level: kernel log level (e.g. KERN_DEBUG)
+ * @prefix_str: string to prefix each line with;
+ * caller supplies trailing spaces for alignment if desired
+ * @prefix_type: controls whether prefix of an offset, address, or none
+ * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)
+ * @rowsize: number of bytes to print per line; must be 16 or 32
+ * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)
+ * @buf: data blob to dump
+ * @len: number of bytes in the @buf
+ * @ascii: include ASCII after the hex output
+ *
+ * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump
+ * to the kernel log at the specified kernel log level, with an optional
+ * leading prefix.
+ *
+ * print_hex_dump() works on one "line" of output at a time, i.e.,
+ * 16 or 32 bytes of input data converted to hex + ASCII output.
+ * print_hex_dump() iterates over the entire input @buf, breaking it into
+ * "line size" chunks to format and print.
+ *
+ * E.g.:
+ * print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,
+ * 16, 1, frame->data, frame->len, true);
+ *
+ * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:
+ * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO
+ * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:
+ * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.
+ */
+void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,
+ int rowsize, int groupsize,
+ const void *buf, size_t len, bool ascii)
+{
+ const u8 *ptr = buf;
+ int i, linelen, remaining = len;
+ unsigned char linebuf[32 * 3 + 2 + 32 + 1];
+
+ if (rowsize != 16 && rowsize != 32)
+ rowsize = 16;
+
+ for (i = 0; i < len; i += rowsize) {
+ linelen = min(remaining, rowsize);
+ remaining -= rowsize;
+
+ hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,
+ linebuf, sizeof(linebuf), ascii);
+
+ switch (prefix_type) {
+ case DUMP_PREFIX_ADDRESS:
+ printk("%s%s%p: %s\n",
+ level, prefix_str, ptr + i, linebuf);
+ break;
+ case DUMP_PREFIX_OFFSET:
+ printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);
+ break;
+ default:
+ printk("%s%s%s\n", level, prefix_str, linebuf);
+ break;
+ }
+ }
+}
+EXPORT_SYMBOL(print_hex_dump);
+
+#endif /* defined(CONFIG_PRINTK) */