lib/hexdump.c - linux - Git at Google

 // 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 <linux/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) */
	// 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 <linux/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) */