+++ /dev/null
->From 9aaec95e82117c1cb0f9624264c3618fc380cecb Mon Sep 17 00:00:00 2001
-From: Mark Adler <madler@alumni.caltech.edu>
-Date: Wed, 21 Sep 2016 22:25:21 -0700
-Subject: [PATCH] Use post-increment only in inffast.c.
-
-An old inffast.c optimization turns out to not be optimal anymore
-with modern compilers, and furthermore was not compliant with the
-C standard, for which decrementing a pointer before its allocated
-memory is undefined. Per the recommendation of a security audit of
-the zlib code by Trail of Bits and TrustInSoft, in support of the
-Mozilla Foundation, this "optimization" was removed, in order to
-avoid the possibility of undefined behavior.
----
- inffast.c | 81 +++++++++++++++++++++----------------------------------
- 1 file changed, 31 insertions(+), 50 deletions(-)
-
-diff --git a/zlib/inffast.c b/zlib/inffast.c
-index bda59ceb..f0d163db 100644
---- a/zlib/inffast.c
-+++ b/zlib/inffast.c
-@@ -10,25 +10,6 @@
-
- #ifndef ASMINF
-
--/* Allow machine dependent optimization for post-increment or pre-increment.
-- Based on testing to date,
-- Pre-increment preferred for:
-- - PowerPC G3 (Adler)
-- - MIPS R5000 (Randers-Pehrson)
-- Post-increment preferred for:
-- - none
-- No measurable difference:
-- - Pentium III (Anderson)
-- - M68060 (Nikl)
-- */
--#ifdef POSTINC
--# define OFF 0
--# define PUP(a) *(a)++
--#else
--# define OFF 1
--# define PUP(a) *++(a)
--#endif
--
- /*
- Decode literal, length, and distance codes and write out the resulting
- literal and match bytes until either not enough input or output is
-@@ -96,9 +77,9 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
-
- /* copy state to local variables */
- state = (struct inflate_state FAR *)strm->state;
-- in = strm->next_in - OFF;
-+ in = strm->next_in;
- last = in + (strm->avail_in - 5);
-- out = strm->next_out - OFF;
-+ out = strm->next_out;
- beg = out - (start - strm->avail_out);
- end = out + (strm->avail_out - 257);
- #ifdef INFLATE_STRICT
-@@ -119,9 +100,9 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
- input data or output space */
- do {
- if (bits < 15) {
-- hold += (unsigned long)(PUP(in)) << bits;
-+ hold += (unsigned long)(*in++) << bits;
- bits += 8;
-- hold += (unsigned long)(PUP(in)) << bits;
-+ hold += (unsigned long)(*in++) << bits;
- bits += 8;
- }
- here = lcode[hold & lmask];
-@@ -134,14 +115,14 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
- Tracevv((stderr, here.val >= 0x20 && here.val < 0x7f ?
- "inflate: literal '%c'\n" :
- "inflate: literal 0x%02x\n", here.val));
-- PUP(out) = (unsigned char)(here.val);
-+ *out++ = (unsigned char)(here.val);
- }
- else if (op & 16) { /* length base */
- len = (unsigned)(here.val);
- op &= 15; /* number of extra bits */
- if (op) {
- if (bits < op) {
-- hold += (unsigned long)(PUP(in)) << bits;
-+ hold += (unsigned long)(*in++) << bits;
- bits += 8;
- }
- len += (unsigned)hold & ((1U << op) - 1);
-@@ -150,9 +131,9 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
- }
- Tracevv((stderr, "inflate: length %u\n", len));
- if (bits < 15) {
-- hold += (unsigned long)(PUP(in)) << bits;
-+ hold += (unsigned long)(*in++) << bits;
- bits += 8;
-- hold += (unsigned long)(PUP(in)) << bits;
-+ hold += (unsigned long)(*in++) << bits;
- bits += 8;
- }
- here = dcode[hold & dmask];
-@@ -165,10 +146,10 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
- dist = (unsigned)(here.val);
- op &= 15; /* number of extra bits */
- if (bits < op) {
-- hold += (unsigned long)(PUP(in)) << bits;
-+ hold += (unsigned long)(*in++) << bits;
- bits += 8;
- if (bits < op) {
-- hold += (unsigned long)(PUP(in)) << bits;
-+ hold += (unsigned long)(*in++) << bits;
- bits += 8;
- }
- }
-@@ -196,30 +177,30 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
- #ifdef INFLATE_ALLOW_INVALID_DISTANCE_TOOFAR_ARRR
- if (len <= op - whave) {
- do {
-- PUP(out) = 0;
-+ *out++ = 0;
- } while (--len);
- continue;
- }
- len -= op - whave;
- do {
-- PUP(out) = 0;
-+ *out++ = 0;
- } while (--op > whave);
- if (op == 0) {
- from = out - dist;
- do {
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
- } while (--len);
- continue;
- }
- #endif
- }
-- from = window - OFF;
-+ from = window;
- if (wnext == 0) { /* very common case */
- from += wsize - op;
- if (op < len) { /* some from window */
- len -= op;
- do {
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
- } while (--op);
- from = out - dist; /* rest from output */
- }
-@@ -230,14 +211,14 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
- if (op < len) { /* some from end of window */
- len -= op;
- do {
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
- } while (--op);
-- from = window - OFF;
-+ from = window;
- if (wnext < len) { /* some from start of window */
- op = wnext;
- len -= op;
- do {
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
- } while (--op);
- from = out - dist; /* rest from output */
- }
-@@ -248,35 +229,35 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
- if (op < len) { /* some from window */
- len -= op;
- do {
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
- } while (--op);
- from = out - dist; /* rest from output */
- }
- }
- while (len > 2) {
-- PUP(out) = PUP(from);
-- PUP(out) = PUP(from);
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
-+ *out++ = *from++;
-+ *out++ = *from++;
- len -= 3;
- }
- if (len) {
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
- if (len > 1)
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
- }
- }
- else {
- from = out - dist; /* copy direct from output */
- do { /* minimum length is three */
-- PUP(out) = PUP(from);
-- PUP(out) = PUP(from);
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
-+ *out++ = *from++;
-+ *out++ = *from++;
- len -= 3;
- } while (len > 2);
- if (len) {
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
- if (len > 1)
-- PUP(out) = PUP(from);
-+ *out++ = *from++;
- }
- }
- }
-@@ -313,8 +294,8 @@ unsigned start; /* inflate()'s starting value for strm->avail_out */
- hold &= (1U << bits) - 1;
-
- /* update state and return */
-- strm->next_in = in + OFF;
-- strm->next_out = out + OFF;
-+ strm->next_in = in;
-+ strm->next_out = out;
- strm->avail_in = (unsigned)(in < last ? 5 + (last - in) : 5 - (in - last));
- strm->avail_out = (unsigned)(out < end ?
- 257 + (end - out) : 257 - (out - end));
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