diff --git a/cache.h b/cache.h
index d00d2be320..c96602305f 100644
--- a/cache.h
+++ b/cache.h
@@ -907,7 +907,7 @@ struct extra_have_objects {
 extern struct ref **get_remote_heads(int in, struct ref **list, int nr_match, char **match, unsigned int flags, struct extra_have_objects *);
 extern int server_supports(const char *feature);
 
-extern struct packed_git *parse_pack_index(unsigned char *sha1);
+extern struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path);
 
 extern void prepare_packed_git(void);
 extern void reprepare_packed_git(void);
@@ -918,6 +918,7 @@ extern struct packed_git *find_sha1_pack(const unsigned char *sha1,
 
 extern void pack_report(void);
 extern int open_pack_index(struct packed_git *);
+extern void close_pack_index(struct packed_git *);
 extern unsigned char *use_pack(struct packed_git *, struct pack_window **, off_t, unsigned int *);
 extern void close_pack_windows(struct packed_git *);
 extern void unuse_pack(struct pack_window **);
diff --git a/http-walker.c b/http-walker.c
index ef99ae647a..8ca76d0507 100644
--- a/http-walker.c
+++ b/http-walker.c
@@ -510,7 +510,7 @@ static int fetch_object(struct walker *walker, struct alt_base *repo, unsigned c
 		ret = error("File %s has bad hash", hex);
 	} else if (req->rename < 0) {
 		ret = error("unable to write sha1 filename %s",
-			    req->filename);
+			    sha1_file_name(req->sha1));
 	}
 
 	release_http_object_request(req);
diff --git a/http.c b/http.c
index 07a03fd79b..1320c50e32 100644
--- a/http.c
+++ b/http.c
@@ -1,6 +1,7 @@
 #include "http.h"
 #include "pack.h"
 #include "sideband.h"
+#include "run-command.h"
 
 int data_received;
 int active_requests;
@@ -914,47 +915,67 @@ int http_fetch_ref(const char *base, struct ref *ref)
 }
 
 /* Helpers for fetching packs */
-static int fetch_pack_index(unsigned char *sha1, const char *base_url)
+static char *fetch_pack_index(unsigned char *sha1, const char *base_url)
 {
-	int ret = 0;
-	char *hex = xstrdup(sha1_to_hex(sha1));
-	char *filename;
-	char *url = NULL;
+	char *url, *tmp;
 	struct strbuf buf = STRBUF_INIT;
 
-	if (has_pack_index(sha1)) {
-		ret = 0;
-		goto cleanup;
-	}
-
 	if (http_is_verbose)
-		fprintf(stderr, "Getting index for pack %s\n", hex);
+		fprintf(stderr, "Getting index for pack %s\n", sha1_to_hex(sha1));
 
 	end_url_with_slash(&buf, base_url);
-	strbuf_addf(&buf, "objects/pack/pack-%s.idx", hex);
+	strbuf_addf(&buf, "objects/pack/pack-%s.idx", sha1_to_hex(sha1));
 	url = strbuf_detach(&buf, NULL);
 
-	filename = sha1_pack_index_name(sha1);
-	if (http_get_file(url, filename, 0) != HTTP_OK)
-		ret = error("Unable to get pack index %s\n", url);
+	strbuf_addf(&buf, "%s.temp", sha1_pack_index_name(sha1));
+	tmp = strbuf_detach(&buf, NULL);
+
+	if (http_get_file(url, tmp, 0) != HTTP_OK) {
+		error("Unable to get pack index %s\n", url);
+		free(tmp);
+		tmp = NULL;
+	}
 
-cleanup:
-	free(hex);
 	free(url);
-	return ret;
+	return tmp;
 }
 
 static int fetch_and_setup_pack_index(struct packed_git **packs_head,
 	unsigned char *sha1, const char *base_url)
 {
 	struct packed_git *new_pack;
+	char *tmp_idx = NULL;
+	int ret;
 
-	if (fetch_pack_index(sha1, base_url))
+	if (has_pack_index(sha1)) {
+		new_pack = parse_pack_index(sha1, NULL);
+		if (!new_pack)
+			return -1; /* parse_pack_index() already issued error message */
+		goto add_pack;
+	}
+
+	tmp_idx = fetch_pack_index(sha1, base_url);
+	if (!tmp_idx)
 		return -1;
 
-	new_pack = parse_pack_index(sha1);
-	if (!new_pack)
+	new_pack = parse_pack_index(sha1, tmp_idx);
+	if (!new_pack) {
+		unlink(tmp_idx);
+		free(tmp_idx);
+
 		return -1; /* parse_pack_index() already issued error message */
+	}
+
+	ret = verify_pack_index(new_pack);
+	if (!ret) {
+		close_pack_index(new_pack);
+		ret = move_temp_to_file(tmp_idx, sha1_pack_index_name(sha1));
+	}
+	free(tmp_idx);
+	if (ret)
+		return -1;
+
+add_pack:
 	new_pack->next = *packs_head;
 	*packs_head = new_pack;
 	return 0;
@@ -1018,37 +1039,62 @@ void release_http_pack_request(struct http_pack_request *preq)
 
 int finish_http_pack_request(struct http_pack_request *preq)
 {
-	int ret;
 	struct packed_git **lst;
+	struct packed_git *p = preq->target;
+	char *tmp_idx;
+	struct child_process ip;
+	const char *ip_argv[8];
 
-	preq->target->pack_size = ftell(preq->packfile);
+	close_pack_index(p);
 
-	if (preq->packfile != NULL) {
-		fclose(preq->packfile);
-		preq->packfile = NULL;
-		preq->slot->local = NULL;
-	}
-
-	ret = move_temp_to_file(preq->tmpfile, preq->filename);
-	if (ret)
-		return ret;
+	fclose(preq->packfile);
+	preq->packfile = NULL;
+	preq->slot->local = NULL;
 
 	lst = preq->lst;
-	while (*lst != preq->target)
+	while (*lst != p)
 		lst = &((*lst)->next);
 	*lst = (*lst)->next;
 
-	if (verify_pack(preq->target))
-		return -1;
-	install_packed_git(preq->target);
+	tmp_idx = xstrdup(preq->tmpfile);
+	strcpy(tmp_idx + strlen(tmp_idx) - strlen(".pack.temp"),
+	       ".idx.temp");
 
+	ip_argv[0] = "index-pack";
+	ip_argv[1] = "-o";
+	ip_argv[2] = tmp_idx;
+	ip_argv[3] = preq->tmpfile;
+	ip_argv[4] = NULL;
+
+	memset(&ip, 0, sizeof(ip));
+	ip.argv = ip_argv;
+	ip.git_cmd = 1;
+	ip.no_stdin = 1;
+	ip.no_stdout = 1;
+
+	if (run_command(&ip)) {
+		unlink(preq->tmpfile);
+		unlink(tmp_idx);
+		free(tmp_idx);
+		return -1;
+	}
+
+	unlink(sha1_pack_index_name(p->sha1));
+
+	if (move_temp_to_file(preq->tmpfile, sha1_pack_name(p->sha1))
+	 || move_temp_to_file(tmp_idx, sha1_pack_index_name(p->sha1))) {
+		free(tmp_idx);
+		return -1;
+	}
+
+	install_packed_git(p);
+	free(tmp_idx);
 	return 0;
 }
 
 struct http_pack_request *new_http_pack_request(
 	struct packed_git *target, const char *base_url)
 {
-	char *filename;
 	long prev_posn = 0;
 	char range[RANGE_HEADER_SIZE];
 	struct strbuf buf = STRBUF_INIT;
@@ -1063,9 +1109,8 @@ struct http_pack_request *new_http_pack_request(
 		sha1_to_hex(target->sha1));
 	preq->url = strbuf_detach(&buf, NULL);
 
-	filename = sha1_pack_name(target->sha1);
-	snprintf(preq->filename, sizeof(preq->filename), "%s", filename);
-	snprintf(preq->tmpfile, sizeof(preq->tmpfile), "%s.temp", filename);
+	snprintf(preq->tmpfile, sizeof(preq->tmpfile), "%s.temp",
+		sha1_pack_name(target->sha1));
 	preq->packfile = fopen(preq->tmpfile, "a");
 	if (!preq->packfile) {
 		error("Unable to open local file %s for pack",
@@ -1100,7 +1145,6 @@ struct http_pack_request *new_http_pack_request(
 	return preq;
 
 abort:
-	free(filename);
 	free(preq->url);
 	free(preq);
 	return NULL;
@@ -1155,7 +1199,6 @@ struct http_object_request *new_http_object_request(const char *base_url,
 	freq->localfile = -1;
 
 	filename = sha1_file_name(sha1);
-	snprintf(freq->filename, sizeof(freq->filename), "%s", filename);
 	snprintf(freq->tmpfile, sizeof(freq->tmpfile),
 		 "%s.temp", filename);
 
@@ -1184,8 +1227,8 @@ struct http_object_request *new_http_object_request(const char *base_url,
 	}
 
 	if (freq->localfile < 0) {
-		error("Couldn't create temporary file %s for %s: %s",
-		      freq->tmpfile, freq->filename, strerror(errno));
+		error("Couldn't create temporary file %s: %s",
+		      freq->tmpfile, strerror(errno));
 		goto abort;
 	}
 
@@ -1232,8 +1275,8 @@ struct http_object_request *new_http_object_request(const char *base_url,
 			prev_posn = 0;
 			lseek(freq->localfile, 0, SEEK_SET);
 			if (ftruncate(freq->localfile, 0) < 0) {
-				error("Couldn't truncate temporary file %s for %s: %s",
-					  freq->tmpfile, freq->filename, strerror(errno));
+				error("Couldn't truncate temporary file %s: %s",
+					  freq->tmpfile, strerror(errno));
 				goto abort;
 			}
 		}
@@ -1309,7 +1352,7 @@ int finish_http_object_request(struct http_object_request *freq)
 		return -1;
 	}
 	freq->rename =
-		move_temp_to_file(freq->tmpfile, freq->filename);
+		move_temp_to_file(freq->tmpfile, sha1_file_name(freq->sha1));
 
 	return freq->rename;
 }
diff --git a/http.h b/http.h
index 37a6a6a3b0..a0b5901594 100644
--- a/http.h
+++ b/http.h
@@ -155,7 +155,6 @@ struct http_pack_request
 	struct packed_git *target;
 	struct packed_git **lst;
 	FILE *packfile;
-	char filename[PATH_MAX];
 	char tmpfile[PATH_MAX];
 	struct curl_slist *range_header;
 	struct active_request_slot *slot;
@@ -170,7 +169,6 @@ extern void release_http_pack_request(struct http_pack_request *preq);
 struct http_object_request
 {
 	char *url;
-	char filename[PATH_MAX];
 	char tmpfile[PATH_MAX];
 	int localfile;
 	CURLcode curl_result;
diff --git a/pack-check.c b/pack-check.c
index 166ca703c1..395fb9527a 100644
--- a/pack-check.c
+++ b/pack-check.c
@@ -133,14 +133,13 @@ static int verify_packfile(struct packed_git *p,
 	return err;
 }
 
-int verify_pack(struct packed_git *p)
+int verify_pack_index(struct packed_git *p)
 {
 	off_t index_size;
 	const unsigned char *index_base;
 	git_SHA_CTX ctx;
 	unsigned char sha1[20];
 	int err = 0;
-	struct pack_window *w_curs = NULL;
 
 	if (open_pack_index(p))
 		return error("packfile %s index not opened", p->pack_name);
@@ -154,8 +153,18 @@ int verify_pack(struct packed_git *p)
 	if (hashcmp(sha1, index_base + index_size - 20))
 		err = error("Packfile index for %s SHA1 mismatch",
 			    p->pack_name);
+	return err;
+}
+
+int verify_pack(struct packed_git *p)
+{
+	int err = 0;
+	struct pack_window *w_curs = NULL;
+
+	err |= verify_pack_index(p);
+	if (!p->index_data)
+		return -1;
 
-	/* Verify pack file */
 	err |= verify_packfile(p, &w_curs);
 	unuse_pack(&w_curs);
 
diff --git a/pack.h b/pack.h
index d268c014c9..bb275762b7 100644
--- a/pack.h
+++ b/pack.h
@@ -57,6 +57,7 @@ struct pack_idx_entry {
 
 extern const char *write_idx_file(const char *index_name, struct pack_idx_entry **objects, int nr_objects, unsigned char *sha1);
 extern int check_pack_crc(struct packed_git *p, struct pack_window **w_curs, off_t offset, off_t len, unsigned int nr);
+extern int verify_pack_index(struct packed_git *);
 extern int verify_pack(struct packed_git *);
 extern void fixup_pack_header_footer(int, unsigned char *, const char *, uint32_t, unsigned char *, off_t);
 extern char *index_pack_lockfile(int fd);
diff --git a/sha1_file.c b/sha1_file.c
index b2074e7a8e..d8e61a65d1 100644
--- a/sha1_file.c
+++ b/sha1_file.c
@@ -599,6 +599,14 @@ void unuse_pack(struct pack_window **w_cursor)
 	}
 }
 
+void close_pack_index(struct packed_git *p)
+{
+	if (p->index_data) {
+		munmap((void *)p->index_data, p->index_size);
+		p->index_data = NULL;
+	}
+}
+
 /*
  * This is used by git-repack in case a newly created pack happens to
  * contain the same set of objects as an existing one.  In that case
@@ -620,8 +628,7 @@ void free_pack_by_name(const char *pack_name)
 			close_pack_windows(p);
 			if (p->pack_fd != -1)
 				close(p->pack_fd);
-			if (p->index_data)
-				munmap((void *)p->index_data, p->index_size);
+			close_pack_index(p);
 			free(p->bad_object_sha1);
 			*pp = p->next;
 			free(p);
@@ -831,9 +838,8 @@ struct packed_git *add_packed_git(const char *path, int path_len, int local)
 	return p;
 }
 
-struct packed_git *parse_pack_index(unsigned char *sha1)
+struct packed_git *parse_pack_index(unsigned char *sha1, const char *idx_path)
 {
-	const char *idx_path = sha1_pack_index_name(sha1);
 	const char *path = sha1_pack_name(sha1);
 	struct packed_git *p = alloc_packed_git(strlen(path) + 1);
 
diff --git a/t/t5550-http-fetch.sh b/t/t5550-http-fetch.sh
index 8cfce969bc..fc675b50ad 100755
--- a/t/t5550-http-fetch.sh
+++ b/t/t5550-http-fetch.sh
@@ -55,12 +55,43 @@ test_expect_success 'http remote detects correct HEAD' '
 
 test_expect_success 'fetch packed objects' '
 	cp -R "$HTTPD_DOCUMENT_ROOT_PATH"/repo.git "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git &&
-	cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git &&
-	git --bare repack &&
-	git --bare prune-packed &&
+	(cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git &&
+	 git --bare repack &&
+	 git --bare prune-packed
+	) &&
 	git clone $HTTPD_URL/dumb/repo_pack.git
 '
 
+test_expect_success 'fetch notices corrupt pack' '
+	cp -R "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git "$HTTPD_DOCUMENT_ROOT_PATH"/repo_bad1.git &&
+	(cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_bad1.git &&
+	 p=`ls objects/pack/pack-*.pack` &&
+	 chmod u+w $p &&
+	 printf %0256d 0 | dd of=$p bs=256 count=1 seek=1 conv=notrunc
+	) &&
+	mkdir repo_bad1.git &&
+	(cd repo_bad1.git &&
+	 git --bare init &&
+	 test_must_fail git --bare fetch $HTTPD_URL/dumb/repo_bad1.git &&
+	 test 0 = `ls objects/pack/pack-*.pack | wc -l`
+	)
+'
+
+test_expect_success 'fetch notices corrupt idx' '
+	cp -R "$HTTPD_DOCUMENT_ROOT_PATH"/repo_pack.git "$HTTPD_DOCUMENT_ROOT_PATH"/repo_bad2.git &&
+	(cd "$HTTPD_DOCUMENT_ROOT_PATH"/repo_bad2.git &&
+	 p=`ls objects/pack/pack-*.idx` &&
+	 chmod u+w $p &&
+	 printf %0256d 0 | dd of=$p bs=256 count=1 seek=1 conv=notrunc
+	) &&
+	mkdir repo_bad2.git &&
+	(cd repo_bad2.git &&
+	 git --bare init &&
+	 test_must_fail git --bare fetch $HTTPD_URL/dumb/repo_bad2.git &&
+	 test 0 = `ls objects/pack | wc -l`
+	)
+'
+
 test_expect_success 'did not use upload-pack service' '
 	grep '/git-upload-pack' <"$HTTPD_ROOT_PATH"/access.log >act
 	: >exp