diff options
Diffstat (limited to 'lib/lzo/lzo1x_decompress_safe.c')
| -rw-r--r-- | lib/lzo/lzo1x_decompress_safe.c | 255 |
1 files changed, 255 insertions, 0 deletions
diff --git a/lib/lzo/lzo1x_decompress_safe.c b/lib/lzo/lzo1x_decompress_safe.c new file mode 100644 index 000000000000..f2fd09850223 --- /dev/null +++ b/lib/lzo/lzo1x_decompress_safe.c @@ -0,0 +1,255 @@ +/* + * LZO1X Decompressor from MiniLZO + * + * Copyright (C) 1996-2005 Markus F.X.J. Oberhumer <markus@oberhumer.com> + * + * The full LZO package can be found at: + * http://www.oberhumer.com/opensource/lzo/ + * + * Changed for kernel use by: + * Nitin Gupta <nitingupta910@gmail.com> + * Richard Purdie <rpurdie@openedhand.com> + */ + +#ifndef STATIC +#include <linux/module.h> +#include <linux/kernel.h> +#endif + +#include <asm/unaligned.h> +#include <linux/lzo.h> +#include "lzodefs.h" + +#define HAVE_IP(x, ip_end, ip) ((size_t)(ip_end - ip) < (x)) +#define HAVE_OP(x, op_end, op) ((size_t)(op_end - op) < (x)) +#define HAVE_LB(m_pos, out, op) (m_pos < out || m_pos >= op) + +#define COPY4(dst, src) \ + put_unaligned(get_unaligned((const u32 *)(src)), (u32 *)(dst)) + +int lzo1x_decompress_safe(const unsigned char *in, size_t in_len, + unsigned char *out, size_t *out_len) +{ + const unsigned char * const ip_end = in + in_len; + unsigned char * const op_end = out + *out_len; + const unsigned char *ip = in, *m_pos; + unsigned char *op = out; + size_t t; + + *out_len = 0; + + if (*ip > 17) { + t = *ip++ - 17; + if (t < 4) + goto match_next; + if (HAVE_OP(t, op_end, op)) + goto output_overrun; + if (HAVE_IP(t + 1, ip_end, ip)) + goto input_overrun; + do { + *op++ = *ip++; + } while (--t > 0); + goto first_literal_run; + } + + while ((ip < ip_end)) { + t = *ip++; + if (t >= 16) + goto match; + if (t == 0) { + if (HAVE_IP(1, ip_end, ip)) + goto input_overrun; + while (*ip == 0) { + t += 255; + ip++; + if (HAVE_IP(1, ip_end, ip)) + goto input_overrun; + } + t += 15 + *ip++; + } + if (HAVE_OP(t + 3, op_end, op)) + goto output_overrun; + if (HAVE_IP(t + 4, ip_end, ip)) + goto input_overrun; + + COPY4(op, ip); + op += 4; + ip += 4; + if (--t > 0) { + if (t >= 4) { + do { + COPY4(op, ip); + op += 4; + ip += 4; + t -= 4; + } while (t >= 4); + if (t > 0) { + do { + *op++ = *ip++; + } while (--t > 0); + } + } else { + do { + *op++ = *ip++; + } while (--t > 0); + } + } + +first_literal_run: + t = *ip++; + if (t >= 16) + goto match; + m_pos = op - (1 + M2_MAX_OFFSET); + m_pos -= t >> 2; + m_pos -= *ip++ << 2; + + if (HAVE_LB(m_pos, out, op)) + goto lookbehind_overrun; + + if (HAVE_OP(3, op_end, op)) + goto output_overrun; + *op++ = *m_pos++; + *op++ = *m_pos++; + *op++ = *m_pos; + + goto match_done; + + do { +match: + if (t >= 64) { + m_pos = op - 1; + m_pos -= (t >> 2) & 7; + m_pos -= *ip++ << 3; + t = (t >> 5) - 1; + if (HAVE_LB(m_pos, out, op)) + goto lookbehind_overrun; + if (HAVE_OP(t + 3 - 1, op_end, op)) + goto output_overrun; + goto copy_match; + } else if (t >= 32) { + t &= 31; + if (t == 0) { + if (HAVE_IP(1, ip_end, ip)) + goto input_overrun; + while (*ip == 0) { + t += 255; + ip++; + if (HAVE_IP(1, ip_end, ip)) + goto input_overrun; + } + t += 31 + *ip++; + } + m_pos = op - 1; + m_pos -= get_unaligned_le16(ip) >> 2; + ip += 2; + } else if (t >= 16) { + m_pos = op; + m_pos -= (t & 8) << 11; + + t &= 7; + if (t == 0) { + if (HAVE_IP(1, ip_end, ip)) + goto input_overrun; + while (*ip == 0) { + t += 255; + ip++; + if (HAVE_IP(1, ip_end, ip)) + goto input_overrun; + } + t += 7 + *ip++; + } + m_pos -= get_unaligned_le16(ip) >> 2; + ip += 2; + if (m_pos == op) + goto eof_found; + m_pos -= 0x4000; + } else { + m_pos = op - 1; + m_pos -= t >> 2; + m_pos -= *ip++ << 2; + + if (HAVE_LB(m_pos, out, op)) + goto lookbehind_overrun; + if (HAVE_OP(2, op_end, op)) + goto output_overrun; + + *op++ = *m_pos++; + *op++ = *m_pos; + goto match_done; + } + + if (HAVE_LB(m_pos, out, op)) + goto lookbehind_overrun; + if (HAVE_OP(t + 3 - 1, op_end, op)) + goto output_overrun; + + if (t >= 2 * 4 - (3 - 1) && (op - m_pos) >= 4) { + COPY4(op, m_pos); + op += 4; + m_pos += 4; + t -= 4 - (3 - 1); + do { + COPY4(op, m_pos); + op += 4; + m_pos += 4; + t -= 4; + } while (t >= 4); + if (t > 0) + do { + *op++ = *m_pos++; + } while (--t > 0); + } else { +copy_match: + *op++ = *m_pos++; + *op++ = *m_pos++; + do { + *op++ = *m_pos++; + } while (--t > 0); + } +match_done: + t = ip[-2] & 3; + if (t == 0) + break; +match_next: + if (HAVE_OP(t, op_end, op)) + goto output_overrun; + if (HAVE_IP(t + 1, ip_end, ip)) + goto input_overrun; + + *op++ = *ip++; + if (t > 1) { + *op++ = *ip++; + if (t > 2) + *op++ = *ip++; + } + + t = *ip++; + } while (ip < ip_end); + } + + *out_len = op - out; + return LZO_E_EOF_NOT_FOUND; + +eof_found: + *out_len = op - out; + return (ip == ip_end ? LZO_E_OK : + (ip < ip_end ? LZO_E_INPUT_NOT_CONSUMED : LZO_E_INPUT_OVERRUN)); +input_overrun: + *out_len = op - out; + return LZO_E_INPUT_OVERRUN; + +output_overrun: + *out_len = op - out; + return LZO_E_OUTPUT_OVERRUN; + +lookbehind_overrun: + *out_len = op - out; + return LZO_E_LOOKBEHIND_OVERRUN; +} +#ifndef STATIC +EXPORT_SYMBOL_GPL(lzo1x_decompress_safe); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("LZO1X Decompressor"); + +#endif |