Commit 1e36c2e2030a9b45260a026ad188a1bd56ebf643
2016-06-16T06:17:54
* src/base/md5.c: Updated to recent version.
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diff --git a/ChangeLog b/ChangeLog
index 044a79d..df164f7 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,7 @@
+2016-06-16 Werner Lemberg <wl@gnu.org>
+
+ * src/base/md5.c: Updated to recent version.
+
2016-06-14 Alexei Podtelezhnikov <apodtele@gmail.com>
* src/smooth/ftgrays.c (gray_hline): Optimize if-condition.
diff --git a/src/base/md5.c b/src/base/md5.c
index 52d96ac..b235e17 100644
--- a/src/base/md5.c
+++ b/src/base/md5.c
@@ -63,12 +63,19 @@
(a) += (b);
/*
- * SET reads 4 input bytes in little-endian byte order and stores them
- * in a properly aligned word in host byte order.
+ * SET reads 4 input bytes in little-endian byte order and stores them in a
+ * properly aligned word in host byte order.
*
- * The check for little-endian architectures that tolerate unaligned
- * memory accesses is just an optimization. Nothing will break if it
- * doesn't work.
+ * The check for little-endian architectures that tolerate unaligned memory
+ * accesses is just an optimization. Nothing will break if it fails to detect
+ * a suitable architecture.
+ *
+ * Unfortunately, this optimization may be a C strict aliasing rules violation
+ * if the caller's data buffer has effective type that cannot be aliased by
+ * MD5_u32plus. In practice, this problem may occur if these MD5 routines are
+ * inlined into a calling function, or with future and dangerously advanced
+ * link-time optimizations. For the time being, keeping these MD5 routines in
+ * their own translation unit avoids the problem.
*/
#if defined(__i386__) || defined(__x86_64__) || defined(__vax__)
#define SET(n) \
@@ -87,8 +94,8 @@
#endif
/*
- * This processes one or more 64-byte data blocks, but does NOT update
- * the bit counters. There are no alignment requirements.
+ * This processes one or more 64-byte data blocks, but does NOT update the bit
+ * counters. There are no alignment requirements.
*/
static const void *body(MD5_CTX *ctx, const void *data, unsigned long size)
{
@@ -242,6 +249,12 @@ void MD5_Update(MD5_CTX *ctx, const void *data, unsigned long size)
memcpy(ctx->buffer, data, size);
}
+#define OUT(dst, src) \
+ (dst)[0] = (unsigned char)(src); \
+ (dst)[1] = (unsigned char)((src) >> 8); \
+ (dst)[2] = (unsigned char)((src) >> 16); \
+ (dst)[3] = (unsigned char)((src) >> 24);
+
void MD5_Final(unsigned char *result, MD5_CTX *ctx)
{
unsigned long used, available;
@@ -262,33 +275,15 @@ void MD5_Final(unsigned char *result, MD5_CTX *ctx)
memset(&ctx->buffer[used], 0, available - 8);
ctx->lo <<= 3;
- ctx->buffer[56] = ctx->lo;
- ctx->buffer[57] = ctx->lo >> 8;
- ctx->buffer[58] = ctx->lo >> 16;
- ctx->buffer[59] = ctx->lo >> 24;
- ctx->buffer[60] = ctx->hi;
- ctx->buffer[61] = ctx->hi >> 8;
- ctx->buffer[62] = ctx->hi >> 16;
- ctx->buffer[63] = ctx->hi >> 24;
+ OUT(&ctx->buffer[56], ctx->lo)
+ OUT(&ctx->buffer[60], ctx->hi)
body(ctx, ctx->buffer, 64);
- result[0] = ctx->a;
- result[1] = ctx->a >> 8;
- result[2] = ctx->a >> 16;
- result[3] = ctx->a >> 24;
- result[4] = ctx->b;
- result[5] = ctx->b >> 8;
- result[6] = ctx->b >> 16;
- result[7] = ctx->b >> 24;
- result[8] = ctx->c;
- result[9] = ctx->c >> 8;
- result[10] = ctx->c >> 16;
- result[11] = ctx->c >> 24;
- result[12] = ctx->d;
- result[13] = ctx->d >> 8;
- result[14] = ctx->d >> 16;
- result[15] = ctx->d >> 24;
+ OUT(&result[0], ctx->a)
+ OUT(&result[4], ctx->b)
+ OUT(&result[8], ctx->c)
+ OUT(&result[12], ctx->d)
memset(ctx, 0, sizeof(*ctx));
}