296 lines · c
1// SPDX-License-Identifier: GPL-2.0-only2/*3 * lib/hexdump.c4 */5 6#include <linux/types.h>7#include <linux/ctype.h>8#include <linux/errno.h>9#include <linux/kernel.h>10#include <linux/minmax.h>11#include <linux/export.h>12#include <linux/unaligned.h>13 14const char hex_asc[] = "0123456789abcdef";15EXPORT_SYMBOL(hex_asc);16const char hex_asc_upper[] = "0123456789ABCDEF";17EXPORT_SYMBOL(hex_asc_upper);18 19/**20 * hex_to_bin - convert a hex digit to its real value21 * @ch: ascii character represents hex digit22 *23 * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad24 * input.25 *26 * This function is used to load cryptographic keys, so it is coded in such a27 * way that there are no conditions or memory accesses that depend on data.28 *29 * Explanation of the logic:30 * (ch - '9' - 1) is negative if ch <= '9'31 * ('0' - 1 - ch) is negative if ch >= '0'32 * we "and" these two values, so the result is negative if ch is in the range33 * '0' ... '9'34 * we are only interested in the sign, so we do a shift ">> 8"; note that right35 * shift of a negative value is implementation-defined, so we cast the36 * value to (unsigned) before the shift --- we have 0xffffff if ch is in37 * the range '0' ... '9', 0 otherwise38 * we "and" this value with (ch - '0' + 1) --- we have a value 1 ... 10 if ch is39 * in the range '0' ... '9', 0 otherwise40 * we add this value to -1 --- we have a value 0 ... 9 if ch is in the range '0'41 * ... '9', -1 otherwise42 * the next line is similar to the previous one, but we need to decode both43 * uppercase and lowercase letters, so we use (ch & 0xdf), which converts44 * lowercase to uppercase45 */46int hex_to_bin(unsigned char ch)47{48 unsigned char cu = ch & 0xdf;49 return -1 +50 ((ch - '0' + 1) & (unsigned)((ch - '9' - 1) & ('0' - 1 - ch)) >> 8) +51 ((cu - 'A' + 11) & (unsigned)((cu - 'F' - 1) & ('A' - 1 - cu)) >> 8);52}53EXPORT_SYMBOL(hex_to_bin);54 55/**56 * hex2bin - convert an ascii hexadecimal string to its binary representation57 * @dst: binary result58 * @src: ascii hexadecimal string59 * @count: result length60 *61 * Return 0 on success, -EINVAL in case of bad input.62 */63int hex2bin(u8 *dst, const char *src, size_t count)64{65 while (count--) {66 int hi, lo;67 68 hi = hex_to_bin(*src++);69 if (unlikely(hi < 0))70 return -EINVAL;71 lo = hex_to_bin(*src++);72 if (unlikely(lo < 0))73 return -EINVAL;74 75 *dst++ = (hi << 4) | lo;76 }77 return 0;78}79EXPORT_SYMBOL(hex2bin);80 81/**82 * bin2hex - convert binary data to an ascii hexadecimal string83 * @dst: ascii hexadecimal result84 * @src: binary data85 * @count: binary data length86 */87char *bin2hex(char *dst, const void *src, size_t count)88{89 const unsigned char *_src = src;90 91 while (count--)92 dst = hex_byte_pack(dst, *_src++);93 return dst;94}95EXPORT_SYMBOL(bin2hex);96 97/**98 * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory99 * @buf: data blob to dump100 * @len: number of bytes in the @buf101 * @rowsize: number of bytes to print per line; must be 16 or 32102 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)103 * @linebuf: where to put the converted data104 * @linebuflen: total size of @linebuf, including space for terminating NUL105 * @ascii: include ASCII after the hex output106 *107 * hex_dump_to_buffer() works on one "line" of output at a time, i.e.,108 * 16 or 32 bytes of input data converted to hex + ASCII output.109 *110 * Given a buffer of u8 data, hex_dump_to_buffer() converts the input data111 * to a hex + ASCII dump at the supplied memory location.112 * The converted output is always NUL-terminated.113 *114 * E.g.:115 * hex_dump_to_buffer(frame->data, frame->len, 16, 1,116 * linebuf, sizeof(linebuf), true);117 *118 * example output buffer:119 * 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO120 *121 * Return:122 * The amount of bytes placed in the buffer without terminating NUL. If the123 * output was truncated, then the return value is the number of bytes124 * (excluding the terminating NUL) which would have been written to the final125 * string if enough space had been available.126 */127int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, int groupsize,128 char *linebuf, size_t linebuflen, bool ascii)129{130 const u8 *ptr = buf;131 int ngroups;132 u8 ch;133 int j, lx = 0;134 int ascii_column;135 int ret;136 137 if (rowsize != 16 && rowsize != 32)138 rowsize = 16;139 140 if (len > rowsize) /* limit to one line at a time */141 len = rowsize;142 if (!is_power_of_2(groupsize) || groupsize > 8)143 groupsize = 1;144 if ((len % groupsize) != 0) /* no mixed size output */145 groupsize = 1;146 147 ngroups = len / groupsize;148 ascii_column = rowsize * 2 + rowsize / groupsize + 1;149 150 if (!linebuflen)151 goto overflow1;152 153 if (!len)154 goto nil;155 156 if (groupsize == 8) {157 const u64 *ptr8 = buf;158 159 for (j = 0; j < ngroups; j++) {160 ret = snprintf(linebuf + lx, linebuflen - lx,161 "%s%16.16llx", j ? " " : "",162 get_unaligned(ptr8 + j));163 if (ret >= linebuflen - lx)164 goto overflow1;165 lx += ret;166 }167 } else if (groupsize == 4) {168 const u32 *ptr4 = buf;169 170 for (j = 0; j < ngroups; j++) {171 ret = snprintf(linebuf + lx, linebuflen - lx,172 "%s%8.8x", j ? " " : "",173 get_unaligned(ptr4 + j));174 if (ret >= linebuflen - lx)175 goto overflow1;176 lx += ret;177 }178 } else if (groupsize == 2) {179 const u16 *ptr2 = buf;180 181 for (j = 0; j < ngroups; j++) {182 ret = snprintf(linebuf + lx, linebuflen - lx,183 "%s%4.4x", j ? " " : "",184 get_unaligned(ptr2 + j));185 if (ret >= linebuflen - lx)186 goto overflow1;187 lx += ret;188 }189 } else {190 for (j = 0; j < len; j++) {191 if (linebuflen < lx + 2)192 goto overflow2;193 ch = ptr[j];194 linebuf[lx++] = hex_asc_hi(ch);195 if (linebuflen < lx + 2)196 goto overflow2;197 linebuf[lx++] = hex_asc_lo(ch);198 if (linebuflen < lx + 2)199 goto overflow2;200 linebuf[lx++] = ' ';201 }202 if (j)203 lx--;204 }205 if (!ascii)206 goto nil;207 208 while (lx < ascii_column) {209 if (linebuflen < lx + 2)210 goto overflow2;211 linebuf[lx++] = ' ';212 }213 for (j = 0; j < len; j++) {214 if (linebuflen < lx + 2)215 goto overflow2;216 ch = ptr[j];217 linebuf[lx++] = (isascii(ch) && isprint(ch)) ? ch : '.';218 }219nil:220 linebuf[lx] = '\0';221 return lx;222overflow2:223 linebuf[lx++] = '\0';224overflow1:225 return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1;226}227EXPORT_SYMBOL(hex_dump_to_buffer);228 229#ifdef CONFIG_PRINTK230/**231 * print_hex_dump - print a text hex dump to syslog for a binary blob of data232 * @level: kernel log level (e.g. KERN_DEBUG)233 * @prefix_str: string to prefix each line with;234 * caller supplies trailing spaces for alignment if desired235 * @prefix_type: controls whether prefix of an offset, address, or none236 * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE)237 * @rowsize: number of bytes to print per line; must be 16 or 32238 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1)239 * @buf: data blob to dump240 * @len: number of bytes in the @buf241 * @ascii: include ASCII after the hex output242 *243 * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump244 * to the kernel log at the specified kernel log level, with an optional245 * leading prefix.246 *247 * print_hex_dump() works on one "line" of output at a time, i.e.,248 * 16 or 32 bytes of input data converted to hex + ASCII output.249 * print_hex_dump() iterates over the entire input @buf, breaking it into250 * "line size" chunks to format and print.251 *252 * E.g.:253 * print_hex_dump(KERN_DEBUG, "raw data: ", DUMP_PREFIX_ADDRESS,254 * 16, 1, frame->data, frame->len, true);255 *256 * Example output using %DUMP_PREFIX_OFFSET and 1-byte mode:257 * 0009ab42: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f @ABCDEFGHIJKLMNO258 * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode:259 * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~.260 */261void print_hex_dump(const char *level, const char *prefix_str, int prefix_type,262 int rowsize, int groupsize,263 const void *buf, size_t len, bool ascii)264{265 const u8 *ptr = buf;266 int i, linelen, remaining = len;267 unsigned char linebuf[32 * 3 + 2 + 32 + 1];268 269 if (rowsize != 16 && rowsize != 32)270 rowsize = 16;271 272 for (i = 0; i < len; i += rowsize) {273 linelen = min(remaining, rowsize);274 remaining -= rowsize;275 276 hex_dump_to_buffer(ptr + i, linelen, rowsize, groupsize,277 linebuf, sizeof(linebuf), ascii);278 279 switch (prefix_type) {280 case DUMP_PREFIX_ADDRESS:281 printk("%s%s%p: %s\n",282 level, prefix_str, ptr + i, linebuf);283 break;284 case DUMP_PREFIX_OFFSET:285 printk("%s%s%.8x: %s\n", level, prefix_str, i, linebuf);286 break;287 default:288 printk("%s%s%s\n", level, prefix_str, linebuf);289 break;290 }291 }292}293EXPORT_SYMBOL(print_hex_dump);294 295#endif /* defined(CONFIG_PRINTK) */296