// SPDX-License-Identifier: GPL-2.0-only /* * lib/hexdump.c */ #include <linux/types.h> #include <linux/ctype.h> #include <linux/errno.h> #include <linux/hex.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) */
