1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * lib/hexdump.c 4 */ 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 <asm/unaligned.h> 13 14 const char hex_asc[] = "0123456789abcdef"; 15 EXPORT_SYMBOL(hex_asc); 16 const char hex_asc_upper[] = "0123456789ABCDEF"; 17 EXPORT_SYMBOL(hex_asc_upper); 18 19 /** 20 * hex_to_bin - convert a hex digit to its real value 21 * @ch: ascii character represents hex digit 22 * 23 * hex_to_bin() converts one hex digit to its actual value or -1 in case of bad 24 * input. 25 * 26 * This function is used to load cryptographic keys, so it is coded in such a 27 * 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 range 33 * '0' ... '9' 34 * we are only interested in the sign, so we do a shift ">> 8"; note that right 35 * shift of a negative value is implementation-defined, so we cast the 36 * value to (unsigned) before the shift --- we have 0xffffff if ch is in 37 * the range '0' ... '9', 0 otherwise 38 * we "and" this value with (ch - '0' + 1) --- we have a value 1 ... 10 if ch is 39 * in the range '0' ... '9', 0 otherwise 40 * we add this value to -1 --- we have a value 0 ... 9 if ch is in the range '0' 41 * ... '9', -1 otherwise 42 * the next line is similar to the previous one, but we need to decode both 43 * uppercase and lowercase letters, so we use (ch & 0xdf), which converts 44 * lowercase to uppercase 45 */ 46 int 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 } 53 EXPORT_SYMBOL(hex_to_bin); 54 55 /** 56 * hex2bin - convert an ascii hexadecimal string to its binary representation 57 * @dst: binary result 58 * @src: ascii hexadecimal string 59 * @count: result length 60 * 61 * Return 0 on success, -EINVAL in case of bad input. 62 */ 63 int 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 } 79 EXPORT_SYMBOL(hex2bin); 80 81 /** 82 * bin2hex - convert binary data to an ascii hexadecimal string 83 * @dst: ascii hexadecimal result 84 * @src: binary data 85 * @count: binary data length 86 */ 87 char *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 } 95 EXPORT_SYMBOL(bin2hex); 96 97 /** 98 * hex_dump_to_buffer - convert a blob of data to "hex ASCII" in memory 99 * @buf: data blob to dump 100 * @len: number of bytes in the @buf 101 * @rowsize: number of bytes to print per line; must be 16 or 32 102 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1) 103 * @linebuf: where to put the converted data 104 * @linebuflen: total size of @linebuf, including space for terminating NUL 105 * @ascii: include ASCII after the hex output 106 * 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 data 111 * 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 @ABCDEFGHIJKLMNO 120 * 121 * Return: 122 * The amount of bytes placed in the buffer without terminating NUL. If the 123 * output was truncated, then the return value is the number of bytes 124 * (excluding the terminating NUL) which would have been written to the final 125 * string if enough space had been available. 126 */ 127 int 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 } 219 nil: 220 linebuf[lx] = '\0'; 221 return lx; 222 overflow2: 223 linebuf[lx++] = '\0'; 224 overflow1: 225 return ascii ? ascii_column + len : (groupsize * 2 + 1) * ngroups - 1; 226 } 227 EXPORT_SYMBOL(hex_dump_to_buffer); 228 229 #ifdef CONFIG_PRINTK 230 /** 231 * print_hex_dump - print a text hex dump to syslog for a binary blob of data 232 * @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 desired 235 * @prefix_type: controls whether prefix of an offset, address, or none 236 * is printed (%DUMP_PREFIX_OFFSET, %DUMP_PREFIX_ADDRESS, %DUMP_PREFIX_NONE) 237 * @rowsize: number of bytes to print per line; must be 16 or 32 238 * @groupsize: number of bytes to print at a time (1, 2, 4, 8; default = 1) 239 * @buf: data blob to dump 240 * @len: number of bytes in the @buf 241 * @ascii: include ASCII after the hex output 242 * 243 * Given a buffer of u8 data, print_hex_dump() prints a hex + ASCII dump 244 * to the kernel log at the specified kernel log level, with an optional 245 * 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 into 250 * "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 @ABCDEFGHIJKLMNO 258 * Example output using %DUMP_PREFIX_ADDRESS and 4-byte mode: 259 * ffffffff88089af0: 73727170 77767574 7b7a7978 7f7e7d7c pqrstuvwxyz{|}~. 260 */ 261 void 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 } 293 EXPORT_SYMBOL(print_hex_dump); 294 295 #endif /* defined(CONFIG_PRINTK) */ 296