diff --git a/builtin/cat-file.c b/builtin/cat-file.c
index 8ed501f220..36a9104433 100644
--- a/builtin/cat-file.c
+++ b/builtin/cat-file.c
@@ -11,6 +11,7 @@
 #include "parse-options.h"
 #include "diff.h"
 #include "userdiff.h"
+#include "streaming.h"
 
 #define BATCH 1
 #define BATCH_CHECK 2
@@ -127,6 +128,8 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name)
 			return cmd_ls_tree(2, ls_args, NULL);
 		}
 
+		if (type == OBJ_BLOB)
+			return stream_blob_to_fd(1, sha1, NULL, 0);
 		buf = read_sha1_file(sha1, &type, &size);
 		if (!buf)
 			die("Cannot read object %s", obj_name);
@@ -149,6 +152,28 @@ static int cat_one_file(int opt, const char *exp_type, const char *obj_name)
 		break;
 
 	case 0:
+		if (type_from_string(exp_type) == OBJ_BLOB) {
+			unsigned char blob_sha1[20];
+			if (sha1_object_info(sha1, NULL) == OBJ_TAG) {
+				enum object_type type;
+				unsigned long size;
+				char *buffer = read_sha1_file(sha1, &type, &size);
+				if (memcmp(buffer, "object ", 7) ||
+				    get_sha1_hex(buffer + 7, blob_sha1))
+					die("%s not a valid tag", sha1_to_hex(sha1));
+				free(buffer);
+			} else
+				hashcpy(blob_sha1, sha1);
+
+			if (sha1_object_info(blob_sha1, NULL) == OBJ_BLOB)
+				return stream_blob_to_fd(1, blob_sha1, NULL, 0);
+			/*
+			 * we attempted to dereference a tag to a blob
+			 * and failed; there may be new dereference
+			 * mechanisms this code is not aware of.
+			 * fall-back to the usual case.
+			 */
+		}
 		buf = read_object_with_reference(sha1, exp_type, &size, NULL);
 		break;
 
diff --git a/builtin/fsck.c b/builtin/fsck.c
index 67eb553c7d..a710227a64 100644
--- a/builtin/fsck.c
+++ b/builtin/fsck.c
@@ -12,6 +12,7 @@
 #include "parse-options.h"
 #include "dir.h"
 #include "progress.h"
+#include "streaming.h"
 
 #define REACHABLE 0x0001
 #define SEEN      0x0002
@@ -238,13 +239,8 @@ static void check_unreachable_object(struct object *obj)
 			if (!(f = fopen(filename, "w")))
 				die_errno("Could not open '%s'", filename);
 			if (obj->type == OBJ_BLOB) {
-				enum object_type type;
-				unsigned long size;
-				char *buf = read_sha1_file(obj->sha1,
-						&type, &size);
-				if (buf && fwrite(buf, 1, size, f) != size)
+				if (stream_blob_to_fd(fileno(f), obj->sha1, NULL, 1))
 					die_errno("Could not write '%s'", filename);
-				free(buf);
 			} else
 				fprintf(f, "%s\n", sha1_to_hex(obj->sha1));
 			if (fclose(f))
diff --git a/builtin/log.c b/builtin/log.c
index 8a47012b0b..690caa7830 100644
--- a/builtin/log.c
+++ b/builtin/log.c
@@ -20,6 +20,7 @@
 #include "string-list.h"
 #include "parse-options.h"
 #include "branch.h"
+#include "streaming.h"
 
 /* Set a default date-time format for git log ("log.date" config variable) */
 static const char *default_date_mode = NULL;
@@ -383,8 +384,13 @@ static void show_tagger(char *buf, int len, struct rev_info *rev)
 	strbuf_release(&out);
 }
 
-static int show_object(const unsigned char *sha1, int show_tag_object,
-	struct rev_info *rev)
+static int show_blob_object(const unsigned char *sha1, struct rev_info *rev)
+{
+	fflush(stdout);
+	return stream_blob_to_fd(1, sha1, NULL, 0);
+}
+
+static int show_tag_object(const unsigned char *sha1, struct rev_info *rev)
 {
 	unsigned long size;
 	enum object_type type;
@@ -394,16 +400,16 @@ static int show_object(const unsigned char *sha1, int show_tag_object,
 	if (!buf)
 		return error(_("Could not read object %s"), sha1_to_hex(sha1));
 
-	if (show_tag_object)
-		while (offset < size && buf[offset] != '\n') {
-			int new_offset = offset + 1;
-			while (new_offset < size && buf[new_offset++] != '\n')
-				; /* do nothing */
-			if (!prefixcmp(buf + offset, "tagger "))
-				show_tagger(buf + offset + 7,
-					    new_offset - offset - 7, rev);
-			offset = new_offset;
-		}
+	assert(type == OBJ_TAG);
+	while (offset < size && buf[offset] != '\n') {
+		int new_offset = offset + 1;
+		while (new_offset < size && buf[new_offset++] != '\n')
+			; /* do nothing */
+		if (!prefixcmp(buf + offset, "tagger "))
+			show_tagger(buf + offset + 7,
+				    new_offset - offset - 7, rev);
+		offset = new_offset;
+	}
 
 	if (offset < size)
 		fwrite(buf + offset, size - offset, 1, stdout);
@@ -463,7 +469,7 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 		const char *name = objects[i].name;
 		switch (o->type) {
 		case OBJ_BLOB:
-			ret = show_object(o->sha1, 0, NULL);
+			ret = show_blob_object(o->sha1, NULL);
 			break;
 		case OBJ_TAG: {
 			struct tag *t = (struct tag *)o;
@@ -474,7 +480,7 @@ int cmd_show(int argc, const char **argv, const char *prefix)
 					diff_get_color_opt(&rev.diffopt, DIFF_COMMIT),
 					t->tag,
 					diff_get_color_opt(&rev.diffopt, DIFF_RESET));
-			ret = show_object(o->sha1, 1, &rev);
+			ret = show_tag_object(o->sha1, &rev);
 			rev.shown_one = 1;
 			if (ret)
 				break;
diff --git a/builtin/update-server-info.c b/builtin/update-server-info.c
index b90dce6358..0d63c4498c 100644
--- a/builtin/update-server-info.c
+++ b/builtin/update-server-info.c
@@ -15,6 +15,7 @@ int cmd_update_server_info(int argc, const char **argv, const char *prefix)
 		OPT_END()
 	};
 
+	git_config(git_default_config, NULL);
 	argc = parse_options(argc, argv, prefix, options,
 			     update_server_info_usage, 0);
 	if (argc > 0)
diff --git a/entry.c b/entry.c
index 852fea1395..17a6bccec6 100644
--- a/entry.c
+++ b/entry.c
@@ -120,58 +120,15 @@ static int streaming_write_entry(struct cache_entry *ce, char *path,
 				 const struct checkout *state, int to_tempfile,
 				 int *fstat_done, struct stat *statbuf)
 {
-	struct git_istream *st;
-	enum object_type type;
-	unsigned long sz;
 	int result = -1;
-	ssize_t kept = 0;
-	int fd = -1;
-
-	st = open_istream(ce->sha1, &type, &sz, filter);
-	if (!st)
-		return -1;
-	if (type != OBJ_BLOB)
-		goto close_and_exit;
+	int fd;
 
 	fd = open_output_fd(path, ce, to_tempfile);
-	if (fd < 0)
-		goto close_and_exit;
-
-	for (;;) {
-		char buf[1024 * 16];
-		ssize_t wrote, holeto;
-		ssize_t readlen = read_istream(st, buf, sizeof(buf));
-
-		if (!readlen)
-			break;
-		if (sizeof(buf) == readlen) {
-			for (holeto = 0; holeto < readlen; holeto++)
-				if (buf[holeto])
-					break;
-			if (readlen == holeto) {
-				kept += holeto;
-				continue;
-			}
-		}
-
-		if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
-			goto close_and_exit;
-		else
-			kept = 0;
-		wrote = write_in_full(fd, buf, readlen);
-
-		if (wrote != readlen)
-			goto close_and_exit;
-	}
-	if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 ||
-		     write(fd, "", 1) != 1))
-		goto close_and_exit;
-	*fstat_done = fstat_output(fd, state, statbuf);
-
-close_and_exit:
-	close_istream(st);
-	if (0 <= fd)
+	if (0 <= fd) {
+		result = stream_blob_to_fd(fd, ce->sha1, filter, 1);
+		*fstat_done = fstat_output(fd, state, statbuf);
 		result = close(fd);
+	}
 	if (result && 0 <= fd)
 		unlink(path);
 	return result;
diff --git a/object.c b/object.c
index 6b06297a5f..0498b18d45 100644
--- a/object.c
+++ b/object.c
@@ -198,6 +198,17 @@ struct object *parse_object(const unsigned char *sha1)
 	if (obj && obj->parsed)
 		return obj;
 
+	if ((obj && obj->type == OBJ_BLOB) ||
+	    (!obj && has_sha1_file(sha1) &&
+	     sha1_object_info(sha1, NULL) == OBJ_BLOB)) {
+		if (check_sha1_signature(repl, NULL, 0, NULL) < 0) {
+			error("sha1 mismatch %s\n", sha1_to_hex(repl));
+			return NULL;
+		}
+		parse_blob_buffer(lookup_blob(sha1), NULL, 0);
+		return lookup_object(sha1);
+	}
+
 	buffer = read_sha1_file(sha1, &type, &size);
 	if (buffer) {
 		if (check_sha1_signature(repl, buffer, size, typename(type)) < 0) {
diff --git a/sha1_file.c b/sha1_file.c
index 4f06a0e450..ad314f08b9 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -19,6 +19,7 @@
 #include "pack-revindex.h"
 #include "sha1-lookup.h"
 #include "bulk-checkin.h"
+#include "streaming.h"
 
 #ifndef O_NOATIME
 #if defined(__linux__) && (defined(__i386__) || defined(__PPC__))
@@ -1146,10 +1147,47 @@ static const struct packed_git *has_packed_and_bad(const unsigned char *sha1)
 	return NULL;
 }
 
-int check_sha1_signature(const unsigned char *sha1, void *map, unsigned long size, const char *type)
+/*
+ * With an in-core object data in "map", rehash it to make sure the
+ * object name actually matches "sha1" to detect object corruption.
+ * With "map" == NULL, try reading the object named with "sha1" using
+ * the streaming interface and rehash it to do the same.
+ */
+int check_sha1_signature(const unsigned char *sha1, void *map,
+			 unsigned long size, const char *type)
 {
 	unsigned char real_sha1[20];
-	hash_sha1_file(map, size, type, real_sha1);
+	enum object_type obj_type;
+	struct git_istream *st;
+	git_SHA_CTX c;
+	char hdr[32];
+	int hdrlen;
+
+	if (map) {
+		hash_sha1_file(map, size, type, real_sha1);
+		return hashcmp(sha1, real_sha1) ? -1 : 0;
+	}
+
+	st = open_istream(sha1, &obj_type, &size, NULL);
+	if (!st)
+		return -1;
+
+	/* Generate the header */
+	hdrlen = sprintf(hdr, "%s %lu", typename(obj_type), size) + 1;
+
+	/* Sha1.. */
+	git_SHA1_Init(&c);
+	git_SHA1_Update(&c, hdr, hdrlen);
+	for (;;) {
+		char buf[1024 * 16];
+		ssize_t readlen = read_istream(st, buf, sizeof(buf));
+
+		if (!readlen)
+			break;
+		git_SHA1_Update(&c, buf, readlen);
+	}
+	git_SHA1_Final(real_sha1, &c);
+	close_istream(st);
 	return hashcmp(sha1, real_sha1) ? -1 : 0;
 }
 
diff --git a/streaming.c b/streaming.c
index 71072e1b1d..7e7ee2be6f 100644
--- a/streaming.c
+++ b/streaming.c
@@ -489,3 +489,58 @@ static open_method_decl(incore)
 
 	return st->u.incore.buf ? 0 : -1;
 }
+
+
+/****************************************************************
+ * Users of streaming interface
+ ****************************************************************/
+
+int stream_blob_to_fd(int fd, unsigned const char *sha1, struct stream_filter *filter,
+		      int can_seek)
+{
+	struct git_istream *st;
+	enum object_type type;
+	unsigned long sz;
+	ssize_t kept = 0;
+	int result = -1;
+
+	st = open_istream(sha1, &type, &sz, filter);
+	if (!st)
+		return result;
+	if (type != OBJ_BLOB)
+		goto close_and_exit;
+	for (;;) {
+		char buf[1024 * 16];
+		ssize_t wrote, holeto;
+		ssize_t readlen = read_istream(st, buf, sizeof(buf));
+
+		if (!readlen)
+			break;
+		if (can_seek && sizeof(buf) == readlen) {
+			for (holeto = 0; holeto < readlen; holeto++)
+				if (buf[holeto])
+					break;
+			if (readlen == holeto) {
+				kept += holeto;
+				continue;
+			}
+		}
+
+		if (kept && lseek(fd, kept, SEEK_CUR) == (off_t) -1)
+			goto close_and_exit;
+		else
+			kept = 0;
+		wrote = write_in_full(fd, buf, readlen);
+
+		if (wrote != readlen)
+			goto close_and_exit;
+	}
+	if (kept && (lseek(fd, kept - 1, SEEK_CUR) == (off_t) -1 ||
+		     write(fd, "", 1) != 1))
+		goto close_and_exit;
+	result = 0;
+
+ close_and_exit:
+	close_istream(st);
+	return result;
+}
diff --git a/streaming.h b/streaming.h
index 589e857b8c..3e827709c8 100644
--- a/streaming.h
+++ b/streaming.h
@@ -12,4 +12,6 @@ extern struct git_istream *open_istream(const unsigned char *, enum object_type
 extern int close_istream(struct git_istream *);
 extern ssize_t read_istream(struct git_istream *, char *, size_t);
 
+extern int stream_blob_to_fd(int fd, const unsigned char *, struct stream_filter *, int can_seek);
+
 #endif /* STREAMING_H */
diff --git a/t/t1050-large.sh b/t/t1050-large.sh
index 29d6024b7f..4d127f19b7 100755
--- a/t/t1050-large.sh
+++ b/t/t1050-large.sh
@@ -6,11 +6,15 @@ test_description='adding and checking out large blobs'
 . ./test-lib.sh
 
 test_expect_success setup '
-	git config core.bigfilethreshold 200k &&
+	# clone does not allow us to pass core.bigfilethreshold to
+	# new repos, so set core.bigfilethreshold globally
+	git config --global core.bigfilethreshold 200k &&
 	echo X | dd of=large1 bs=1k seek=2000 &&
 	echo X | dd of=large2 bs=1k seek=2000 &&
 	echo X | dd of=large3 bs=1k seek=2000 &&
-	echo Y | dd of=huge bs=1k seek=2500
+	echo Y | dd of=huge bs=1k seek=2500 &&
+	GIT_ALLOC_LIMIT=1500 &&
+	export GIT_ALLOC_LIMIT
 '
 
 test_expect_success 'add a large file or two' '
@@ -100,4 +104,34 @@ test_expect_success 'packsize limit' '
 	)
 '
 
+test_expect_success 'diff --raw' '
+	git commit -q -m initial &&
+	echo modified >>large1 &&
+	git add large1 &&
+	git commit -q -m modified &&
+	git diff --raw HEAD^
+'
+
+test_expect_success 'hash-object' '
+	git hash-object large1
+'
+
+test_expect_success 'cat-file a large file' '
+	git cat-file blob :large1 >/dev/null
+'
+
+test_expect_success 'cat-file a large file from a tag' '
+	git tag -m largefile largefiletag :large1 &&
+	git cat-file blob largefiletag >/dev/null
+'
+
+test_expect_success 'git-show a large file' '
+	git show :large1 >/dev/null
+
+'
+
+test_expect_success 'repack' '
+	git repack -ad
+'
+
 test_done
diff --git a/wrapper.c b/wrapper.c
index 85f09df747..6ccd0595f4 100644
--- a/wrapper.c
+++ b/wrapper.c
@@ -9,6 +9,18 @@ static void do_nothing(size_t size)
 
 static void (*try_to_free_routine)(size_t size) = do_nothing;
 
+static void memory_limit_check(size_t size)
+{
+	static int limit = -1;
+	if (limit == -1) {
+		const char *env = getenv("GIT_ALLOC_LIMIT");
+		limit = env ? atoi(env) * 1024 : 0;
+	}
+	if (limit && size > limit)
+		die("attempting to allocate %"PRIuMAX" over limit %d",
+		    (intmax_t)size, limit);
+}
+
 try_to_free_t set_try_to_free_routine(try_to_free_t routine)
 {
 	try_to_free_t old = try_to_free_routine;
@@ -32,7 +44,10 @@ char *xstrdup(const char *str)
 
 void *xmalloc(size_t size)
 {
-	void *ret = malloc(size);
+	void *ret;
+
+	memory_limit_check(size);
+	ret = malloc(size);
 	if (!ret && !size)
 		ret = malloc(1);
 	if (!ret) {
@@ -79,7 +94,10 @@ char *xstrndup(const char *str, size_t len)
 
 void *xrealloc(void *ptr, size_t size)
 {
-	void *ret = realloc(ptr, size);
+	void *ret;
+
+	memory_limit_check(size);
+	ret = realloc(ptr, size);
 	if (!ret && !size)
 		ret = realloc(ptr, 1);
 	if (!ret) {
@@ -95,7 +113,10 @@ void *xrealloc(void *ptr, size_t size)
 
 void *xcalloc(size_t nmemb, size_t size)
 {
-	void *ret = calloc(nmemb, size);
+	void *ret;
+
+	memory_limit_check(size * nmemb);
+	ret = calloc(nmemb, size);
 	if (!ret && (!nmemb || !size))
 		ret = calloc(1, 1);
 	if (!ret) {