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Diffstat (limited to 'lib/lz4/lz4_decompress.c')
-rw-r--r--lib/lz4/lz4_decompress.c295
1 files changed, 134 insertions, 161 deletions
diff --git a/lib/lz4/lz4_decompress.c b/lib/lz4/lz4_decompress.c
index 6d940c72b5fc..0f3e42dd01b0 100644
--- a/lib/lz4/lz4_decompress.c
+++ b/lib/lz4/lz4_decompress.c
@@ -43,111 +43,99 @@
#endif
#include <linux/lz4.h>
-#include <asm/unaligned.h>
-
#include "lz4defs.h"
-static const int dec32table[] = {0, 3, 2, 3, 0, 0, 0, 0};
+static const int dec32table[8] = {0, 3, 2, 3, 0, 0, 0, 0};
#if LZ4_ARCH64
-static const int dec64table[] = {0, 0, 0, -1, 0, 1, 2, 3};
+static const int dec64table[8] = {0, 0, 0, -1, 0, 1, 2, 3};
+#else
+static const int dec64table[8] = {0, 0, 0, 0, 0, 0, 0, 0};
#endif
-static int lz4_uncompress(const char *source, char *dest, int osize)
+static inline size_t get_length(const u8 **ip, size_t length)
{
- const BYTE *ip = (const BYTE *) source;
- const BYTE *ref;
- BYTE *op = (BYTE *) dest;
- BYTE * const oend = op + osize;
- BYTE *cpy;
- unsigned token;
- size_t length;
+ if (length == LENGTH_LONG) {
+ size_t len;
- while (1) {
+ do {
+ length += (len = *(*ip)++);
+ } while (len == 255);
+ }
+
+ return length;
+}
+
+static int lz4_uncompress(const u8 *source, u8 *dest, int osize)
+{
+ const u8 *ip = source;
+ const u8 *ref;
+ u8 *op = dest;
+ u8 * const oend = op + osize;
+ u8 *cpy;
+ unsigned token, offset;
+ ssize_t length;
+ while (1) {
/* get runlength */
token = *ip++;
- length = (token >> ML_BITS);
- if (length == RUN_MASK) {
- size_t len;
-
- len = *ip++;
- for (; len == 255; length += 255)
- len = *ip++;
- if (unlikely(length > (size_t)(length + len)))
- goto _output_error;
- length += len;
- }
+ length = get_length(&ip, token >> ML_BITS);
/* copy literals */
- cpy = op + length;
- if (unlikely(cpy > oend - COPYLENGTH)) {
+ if (unlikely(op + length > oend - COPYLENGTH)) {
/*
* Error: not enough place for another match
* (min 4) + 5 literals
*/
- if (cpy != oend)
+ if (op + length != oend)
goto _output_error;
- memcpy(op, ip, length);
- ip += length;
+ MEMCPY_ADVANCE(op, ip, length);
break; /* EOF */
}
- LZ4_WILDCOPY(ip, op, cpy);
- ip -= (op - cpy);
- op = cpy;
+ MEMCPY_ADVANCE_CHUNKED(op, ip, length);
- /* get offset */
- LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
- ip += 2;
+ /* get match offset */
+ offset = GET_LE16_ADVANCE(ip);
+ ref = op - offset;
/* Error: offset create reference outside destination buffer */
- if (unlikely(ref < (BYTE *const) dest))
+ if (unlikely(ref < (u8 *const) dest))
goto _output_error;
- /* get matchlength */
- length = token & ML_MASK;
- if (length == ML_MASK) {
- for (; *ip == 255; length += 255)
- ip++;
- if (unlikely(length > (size_t)(length + *ip)))
- goto _output_error;
- length += *ip++;
- }
+ /* get match length */
+ length = get_length(&ip, token & ML_MASK);
+ length += MINMATCH;
- /* copy repeated sequence */
- if (unlikely((op - ref) < STEPSIZE)) {
-#if LZ4_ARCH64
- int dec64 = dec64table[op - ref];
-#else
- const int dec64 = 0;
-#endif
- op[0] = ref[0];
- op[1] = ref[1];
- op[2] = ref[2];
- op[3] = ref[3];
- op += 4;
- ref += 4;
- ref -= dec32table[op-ref];
- PUT4(ref, op);
+ /* copy first STEPSIZE bytes of match: */
+ if (unlikely(offset < STEPSIZE)) {
+ MEMCPY_ADVANCE_BYTES(op, ref, 4);
+ ref -= dec32table[offset];
+
+ memcpy(op, ref, 4);
op += STEPSIZE - 4;
- ref -= dec64;
+ ref -= dec64table[offset];
} else {
- LZ4_COPYSTEP(ref, op);
+ MEMCPY_ADVANCE(op, ref, STEPSIZE);
}
- cpy = op + length - (STEPSIZE - 4);
- if (cpy > (oend - COPYLENGTH)) {
+ length -= STEPSIZE;
+ /*
+ * Note - length could have been < STEPSIZE; that's ok, length
+ * will now be negative and we'll just end up rewinding op:
+ */
+ /* copy rest of match: */
+ cpy = op + length;
+ if (cpy > oend - COPYLENGTH) {
/* Error: request to write beyond destination buffer */
- if (cpy > oend)
+ if (cpy > oend ||
+ ref + COPYLENGTH > oend)
goto _output_error;
-#if LZ4_ARCH64
- if ((ref + COPYLENGTH) > oend)
-#else
- if ((ref + COPYLENGTH) > oend ||
- (op + COPYLENGTH) > oend)
-#endif
+#if !LZ4_ARCH64
+ if (op + COPYLENGTH > oend)
goto _output_error;
- LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
+#endif
+ MEMCPY_ADVANCE_CHUNKED_NOFIXUP(op, ref, oend - COPYLENGTH);
+ /* op could be > cpy here */
while (op < cpy)
*op++ = *ref++;
op = cpy;
@@ -157,55 +145,60 @@ static int lz4_uncompress(const char *source, char *dest, int osize)
*/
if (op == oend)
goto _output_error;
- continue;
+ } else {
+ MEMCPY_ADVANCE_CHUNKED(op, ref, length);
}
- LZ4_SECURECOPY(ref, op, cpy);
- op = cpy; /* correction */
}
/* end of decoding */
- return (int) (((char *)ip) - source);
+ return ip - source;
/* write overflow error detected */
_output_error:
return -1;
}
-static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
- int isize, size_t maxoutputsize)
+static inline ssize_t get_length_safe(const u8 **ip, ssize_t length)
{
- const BYTE *ip = (const BYTE *) source;
- const BYTE *const iend = ip + isize;
- const BYTE *ref;
+ if (length == 15) {
+ size_t len;
+ do {
+ length += (len = *(*ip)++);
+ if (unlikely((ssize_t) length < 0))
+ return -1;
- BYTE *op = (BYTE *) dest;
- BYTE * const oend = op + maxoutputsize;
- BYTE *cpy;
+ length += len;
+ } while (len == 255);
+ }
- /* Main Loop */
- while (ip < iend) {
+ return length;
+}
- unsigned token;
- size_t length;
+static int lz4_uncompress_unknownoutputsize(const u8 *source, u8 *dest,
+ int isize, size_t maxoutputsize)
+{
+ const u8 *ip = source;
+ const u8 *const iend = ip + isize;
+ const u8 *ref;
+ u8 *op = dest;
+ u8 * const oend = op + maxoutputsize;
+ u8 *cpy;
+ unsigned token, offset;
+ size_t length;
+ /* Main Loop */
+ while (ip < iend) {
/* get runlength */
token = *ip++;
- length = (token >> ML_BITS);
- if (length == RUN_MASK) {
- int s = 255;
- while ((ip < iend) && (s == 255)) {
- s = *ip++;
- if (unlikely(length > (size_t)(length + s)))
- goto _output_error;
- length += s;
- }
- }
+ length = get_length_safe(&ip, token >> ML_BITS);
+ if (unlikely((ssize_t) length < 0))
+ goto _output_error;
+
/* copy literals */
- cpy = op + length;
- if ((cpy > oend - COPYLENGTH) ||
- (ip + length > iend - COPYLENGTH)) {
+ if ((op + length > oend - COPYLENGTH) ||
+ (ip + length > iend - COPYLENGTH)) {
- if (cpy > oend)
+ if (op + length > oend)
goto _output_error;/* writes beyond buffer */
if (ip + length != iend)
@@ -214,70 +207,51 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
* to consume all input
* at this stage
*/
- memcpy(op, ip, length);
- op += length;
+ MEMCPY_ADVANCE(op, ip, length);
break;/* Necessarily EOF, due to parsing restrictions */
}
- LZ4_WILDCOPY(ip, op, cpy);
- ip -= (op - cpy);
- op = cpy;
-
- /* get offset */
- LZ4_READ_LITTLEENDIAN_16(ref, cpy, ip);
- ip += 2;
- if (ref < (BYTE * const) dest)
+ MEMCPY_ADVANCE_CHUNKED(op, ip, length);
+
+ /* get match offset */
+ offset = GET_LE16_ADVANCE(ip);
+ ref = op - offset;
+
+ /* Error: offset create reference outside destination buffer */
+ if (ref < (u8 * const) dest)
goto _output_error;
- /*
- * Error : offset creates reference
- * outside of destination buffer
- */
- /* get matchlength */
- length = (token & ML_MASK);
- if (length == ML_MASK) {
- while (ip < iend) {
- int s = *ip++;
- if (unlikely(length > (size_t)(length + s)))
- goto _output_error;
- length += s;
- if (s == 255)
- continue;
- break;
- }
- }
+ /* get match length */
+ length = get_length_safe(&ip, token & ML_MASK);
+ if (unlikely((ssize_t) length < 0))
+ goto _output_error;
- /* copy repeated sequence */
- if (unlikely((op - ref) < STEPSIZE)) {
-#if LZ4_ARCH64
- int dec64 = dec64table[op - ref];
-#else
- const int dec64 = 0;
-#endif
- op[0] = ref[0];
- op[1] = ref[1];
- op[2] = ref[2];
- op[3] = ref[3];
- op += 4;
- ref += 4;
- ref -= dec32table[op - ref];
- PUT4(ref, op);
- op += STEPSIZE - 4;
- ref -= dec64;
+ length += MINMATCH;
+
+ /* copy first STEPSIZE bytes of match: */
+ if (unlikely(offset < STEPSIZE)) {
+ MEMCPY_ADVANCE_BYTES(op, ref, 4);
+ ref -= dec32table[offset];
+
+ memcpy(op, ref, 4);
+ op += STEPSIZE - 4;
+ ref -= dec64table[offset];
} else {
- LZ4_COPYSTEP(ref, op);
+ MEMCPY_ADVANCE(op, ref, STEPSIZE);
}
- cpy = op + length - (STEPSIZE-4);
+ length -= STEPSIZE;
+
+ /* copy rest of match: */
+ cpy = op + length;
if (cpy > oend - COPYLENGTH) {
- if (cpy > oend)
- goto _output_error; /* write outside of buf */
-#if LZ4_ARCH64
- if ((ref + COPYLENGTH) > oend)
-#else
- if ((ref + COPYLENGTH) > oend ||
- (op + COPYLENGTH) > oend)
-#endif
+ /* Error: request to write beyond destination buffer */
+ if (cpy > oend ||
+ ref + COPYLENGTH > oend)
+ goto _output_error;
+#if !LZ4_ARCH64
+ if (op + COPYLENGTH > oend)
goto _output_error;
- LZ4_SECURECOPY(ref, op, (oend - COPYLENGTH));
+#endif
+ MEMCPY_ADVANCE_CHUNKED_NOFIXUP(op, ref, oend - COPYLENGTH);
while (op < cpy)
*op++ = *ref++;
op = cpy;
@@ -287,13 +261,12 @@ static int lz4_uncompress_unknownoutputsize(const char *source, char *dest,
*/
if (op == oend)
goto _output_error;
- continue;
+ } else {
+ MEMCPY_ADVANCE_CHUNKED(op, ref, length);
}
- LZ4_SECURECOPY(ref, op, cpy);
- op = cpy; /* correction */
}
/* end of decoding */
- return (int) (((char *) op) - dest);
+ return op - dest;
/* write overflow error detected */
_output_error:
generated by cgit v1.2.3 (git 2.46.0) at 2025-07-01 12:20:26 +0000