diff options
| -rw-r--r-- | include/linux/printk.h | 6 | ||||
| -rw-r--r-- | lib/hexdump.c | 73 | ||||
| -rw-r--r-- | lib/test-hexdump.c | 45 |
3 files changed, 103 insertions, 21 deletions
diff --git a/include/linux/printk.h b/include/linux/printk.h index 4d5bf5726578..baa3f97d8ce8 100644 --- a/include/linux/printk.h +++ b/include/linux/printk.h @@ -417,9 +417,9 @@ enum { DUMP_PREFIX_ADDRESS, DUMP_PREFIX_OFFSET }; -extern void hex_dump_to_buffer(const void *buf, size_t len, - int rowsize, int groupsize, - char *linebuf, size_t linebuflen, bool ascii); +extern int hex_dump_to_buffer(const void *buf, size_t len, int rowsize, + int groupsize, char *linebuf, size_t linebuflen, + bool ascii); #ifdef CONFIG_PRINTK extern void print_hex_dump(const char *level, const char *prefix_str, int prefix_type, int rowsize, int groupsize, diff --git a/lib/hexdump.c b/lib/hexdump.c index 4af53f73c7cc..7ea09699855d 100644 --- a/lib/hexdump.c +++ b/lib/hexdump.c @@ -97,22 +97,26 @@ EXPORT_SYMBOL(bin2hex); * * 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. */ -void hex_dump_to_buffer(const void *buf, size_t len, int rowsize, - int groupsize, char *linebuf, size_t linebuflen, - bool ascii) +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) - goto nil; if (len > rowsize) /* limit to one line at a time */ len = rowsize; if (!is_power_of_2(groupsize) || groupsize > 8) @@ -122,27 +126,50 @@ void hex_dump_to_buffer(const void *buf, size_t len, int rowsize, 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++) - lx += scnprintf(linebuf + lx, linebuflen - lx, - "%s%16.16llx", j ? " " : "", - (unsigned long long)*(ptr8 + j)); + for (j = 0; j < ngroups; j++) { + ret = snprintf(linebuf + lx, linebuflen - lx, + "%s%16.16llx", j ? " " : "", + (unsigned long long)*(ptr8 + j)); + if (ret >= linebuflen - lx) + goto overflow1; + lx += ret; + } } else if (groupsize == 4) { const u32 *ptr4 = buf; - for (j = 0; j < ngroups; j++) - lx += scnprintf(linebuf + lx, linebuflen - lx, - "%s%8.8x", j ? " " : "", *(ptr4 + j)); + for (j = 0; j < ngroups; j++) { + ret = snprintf(linebuf + lx, linebuflen - lx, + "%s%8.8x", j ? " " : "", + *(ptr4 + j)); + if (ret >= linebuflen - lx) + goto overflow1; + lx += ret; + } } else if (groupsize == 2) { const u16 *ptr2 = buf; - for (j = 0; j < ngroups; j++) - lx += scnprintf(linebuf + lx, linebuflen - lx, - "%s%4.4x", j ? " " : "", *(ptr2 + j)); + for (j = 0; j < ngroups; j++) { + ret = snprintf(linebuf + lx, linebuflen - lx, + "%s%4.4x", j ? " " : "", + *(ptr2 + j)); + if (ret >= linebuflen - lx) + goto overflow1; + lx += ret; + } } else { - for (j = 0; (j < len) && (lx + 3) <= linebuflen; j++) { + for (j = 0; j < len; j++) { + if (linebuflen < lx + 3) + goto overflow2; ch = ptr[j]; linebuf[lx++] = hex_asc_hi(ch); linebuf[lx++] = hex_asc_lo(ch); @@ -154,14 +181,24 @@ void hex_dump_to_buffer(const void *buf, size_t len, int rowsize, if (!ascii) goto nil; - while (lx < (linebuflen - 1) && lx < ascii_column) + while (lx < ascii_column) { + if (linebuflen < lx + 2) + goto overflow2; linebuf[lx++] = ' '; - for (j = 0; (j < len) && (lx + 2) < linebuflen; j++) { + } + 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); diff --git a/lib/test-hexdump.c b/lib/test-hexdump.c index 9d3bd1e9ae48..daf29a390a89 100644 --- a/lib/test-hexdump.c +++ b/lib/test-hexdump.c @@ -114,6 +114,45 @@ static void __init test_hexdump_set(int rowsize, bool ascii) test_hexdump(len, rowsize, 1, ascii); } +static void __init test_hexdump_overflow(bool ascii) +{ + char buf[56]; + const char *t = test_data_1_le[0]; + size_t l = get_random_int() % sizeof(buf); + bool a; + int e, r; + + memset(buf, ' ', sizeof(buf)); + + r = hex_dump_to_buffer(data_b, 1, 16, 1, buf, l, ascii); + + if (ascii) + e = 50; + else + e = 2; + buf[e + 2] = '\0'; + + if (!l) { + a = r == e && buf[0] == ' '; + } else if (l < 3) { + a = r == e && buf[0] == '\0'; + } else if (l < 4) { + a = r == e && !strcmp(buf, t); + } else if (ascii) { + if (l < 51) + a = r == e && buf[l - 1] == '\0' && buf[l - 2] == ' '; + else + a = r == e && buf[50] == '\0' && buf[49] == '.'; + } else { + a = r == e && buf[e] == '\0'; + } + + if (!a) { + pr_err("Len: %zu rc: %u strlen: %zu\n", l, r, strlen(buf)); + pr_err("Result: '%s'\n", buf); + } +} + static int __init test_hexdump_init(void) { unsigned int i; @@ -129,6 +168,12 @@ static int __init test_hexdump_init(void) for (i = 0; i < 16; i++) test_hexdump_set(rowsize, true); + for (i = 0; i < 16; i++) + test_hexdump_overflow(false); + + for (i = 0; i < 16; i++) + test_hexdump_overflow(true); + return -EINVAL; } module_init(test_hexdump_init); |