Merge branch 'jk/xdiff-memory-limits' into maint-2.3

11 files changed, 57 insertions, 26 deletions

diff --git a/builtin/blame.c b/builtin/blame.c
index 2b1f9dd6c..66b4fbf46 100644
--- a/builtin/blame.c
+++ b/builtin/blame.c
@@ -972,7 +972,10 @@ static void pass_blame_to_parent(struct scoreboard *sb,
 	fill_origin_blob(&sb->revs->diffopt, target, &file_o);
 	num_get_patch++;
 
-	diff_hunks(&file_p, &file_o, 0, blame_chunk_cb, &d);
+	if (diff_hunks(&file_p, &file_o, 0, blame_chunk_cb, &d))
+		die("unable to generate diff (%s -> %s)",
+		    sha1_to_hex(parent->commit->object.sha1),
+		    sha1_to_hex(target->commit->object.sha1));
 	/* The rest are the same as the parent */
 	blame_chunk(&d.dstq, &d.srcq, INT_MAX, d.offset, INT_MAX, parent);
 	*d.dstq = NULL;
@@ -1118,7 +1121,9 @@ static void find_copy_in_blob(struct scoreboard *sb,
 	 * file_p partially may match that image.
 	 */
 	memset(split, 0, sizeof(struct blame_entry [3]));
-	diff_hunks(file_p, &file_o, 1, handle_split_cb, &d);
+	if (diff_hunks(file_p, &file_o, 1, handle_split_cb, &d))
+		die("unable to generate diff (%s)",
+		    sha1_to_hex(parent->commit->object.sha1));
 	/* remainder, if any, all match the preimage */
 	handle_split(sb, ent, d.tlno, d.plno, ent->num_lines, parent, split);
 }
diff --git a/builtin/merge-file.c b/builtin/merge-file.c
index 232b76857..04ae36a45 100644
--- a/builtin/merge-file.c
+++ b/builtin/merge-file.c
@@ -75,7 +75,8 @@ int cmd_merge_file(int argc, const char **argv, const char *prefix)
 			names[i] = argv[i];
 		if (read_mmfile(mmfs + i, fname))
 			return -1;
-		if (buffer_is_binary(mmfs[i].ptr, mmfs[i].size))
+		if (mmfs[i].size > MAX_XDIFF_SIZE ||
+		    buffer_is_binary(mmfs[i].ptr, mmfs[i].size))
 			return error("Cannot merge binary files: %s",
 					argv[i]);
 	}
diff --git a/builtin/merge-tree.c b/builtin/merge-tree.c
index f9ab48597..2a4aafec6 100644
--- a/builtin/merge-tree.c
+++ b/builtin/merge-tree.c
@@ -118,7 +118,8 @@ static void show_diff(struct merge_list *entry)
 	if (!dst.ptr)
 		size = 0;
 	dst.size = size;
-	xdi_diff(&src, &dst, &xpp, &xecfg, &ecb);
+	if (xdi_diff(&src, &dst, &xpp, &xecfg, &ecb))
+		die("unable to generate diff");
 	free(src.ptr);
 	free(dst.ptr);
 }
diff --git a/builtin/rerere.c b/builtin/rerere.c
index 98eb8c540..aab8f3b1f 100644
--- a/builtin/rerere.c
+++ b/builtin/rerere.c
@@ -29,9 +29,10 @@ static int diff_two(const char *file1, const char *label1,
 	xdemitconf_t xecfg;
 	xdemitcb_t ecb;
 	mmfile_t minus, plus;
+	int ret;
 
 	if (read_mmfile(&minus, file1) || read_mmfile(&plus, file2))
-		return 1;
+		return -1;
 
 	printf("--- a/%s\n+++ b/%s\n", label1, label2);
 	fflush(stdout);
@@ -40,11 +41,11 @@ static int diff_two(const char *file1, const char *label1,
 	memset(&xecfg, 0, sizeof(xecfg));
 	xecfg.ctxlen = 3;
 	ecb.outf = outf;
-	xdi_diff(&minus, &plus, &xpp, &xecfg, &ecb);
+	ret = xdi_diff(&minus, &plus, &xpp, &xecfg, &ecb);
 
 	free(minus.ptr);
 	free(plus.ptr);
-	return 0;
+	return ret;
 }
 
 int cmd_rerere(int argc, const char **argv, const char *prefix)
@@ -104,7 +105,8 @@ int cmd_rerere(int argc, const char **argv, const char *prefix)
 		for (i = 0; i < merge_rr.nr; i++) {
 			const char *path = merge_rr.items[i].string;
 			const char *name = (const char *)merge_rr.items[i].util;
-			diff_two(rerere_path(name, "preimage"), path, path, path);
+			if (diff_two(rerere_path(name, "preimage"), path, path, path))
+				die("unable to generate diff for %s", name);
 		}
 	else
 		usage_with_options(rerere_usage, options);
diff --git a/combine-diff.c b/combine-diff.c
index 91edce58e..284bec6ad 100644
--- a/combine-diff.c
+++ b/combine-diff.c
@@ -419,8 +419,10 @@ static void combine_diff(const unsigned char *parent, unsigned int mode,
 	state.num_parent = num_parent;
 	state.n = n;
 
-	xdi_diff_outf(&parent_file, result_file, consume_line, &state,
-		      &xpp, &xecfg);
+	if (xdi_diff_outf(&parent_file, result_file, consume_line, &state,
+			  &xpp, &xecfg))
+		die("unable to generate combined diff for %s",
+		    sha1_to_hex(parent));
 	free(parent_file.ptr);
 
 	/* Assign line numbers for this parent.
diff --git a/diff.c b/diff.c
index 7500c5509..6bbf28bff 100644
--- a/diff.c
+++ b/diff.c
@@ -1002,8 +1002,9 @@ static void diff_words_show(struct diff_words_data *diff_words)
 	xpp.flags = 0;
 	/* as only the hunk header will be parsed, we need a 0-context */
 	xecfg.ctxlen = 0;
-	xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
-		      &xpp, &xecfg);
+	if (xdi_diff_outf(&minus, &plus, fn_out_diff_words_aux, diff_words,
+			  &xpp, &xecfg))
+		die("unable to generate word diff");
 	free(minus.ptr);
 	free(plus.ptr);
 	if (diff_words->current_plus != diff_words->plus.text.ptr +
@@ -2400,8 +2401,9 @@ static void builtin_diff(const char *name_a,
 			xecfg.ctxlen = strtoul(v, NULL, 10);
 		if (o->word_diff)
 			init_diff_words_data(&ecbdata, o, one, two);
-		xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
-			      &xpp, &xecfg);
+		if (xdi_diff_outf(&mf1, &mf2, fn_out_consume, &ecbdata,
+				  &xpp, &xecfg))
+			die("unable to generate diff for %s", one->path);
 		if (o->word_diff)
 			free_diff_words_data(&ecbdata);
 		if (textconv_one)
@@ -2478,8 +2480,9 @@ static void builtin_diffstat(const char *name_a, const char *name_b,
 		xpp.flags = o->xdl_opts;
 		xecfg.ctxlen = o->context;
 		xecfg.interhunkctxlen = o->interhunkcontext;
-		xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
-			      &xpp, &xecfg);
+		if (xdi_diff_outf(&mf1, &mf2, diffstat_consume, diffstat,
+				  &xpp, &xecfg))
+			die("unable to generate diffstat for %s", one->path);
 	}
 
 	diff_free_filespec_data(one);
@@ -2525,8 +2528,9 @@ static void builtin_checkdiff(const char *name_a, const char *name_b,
 		memset(&xecfg, 0, sizeof(xecfg));
 		xecfg.ctxlen = 1; /* at least one context line */
 		xpp.flags = 0;
-		xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
-			      &xpp, &xecfg);
+		if (xdi_diff_outf(&mf1, &mf2, checkdiff_consume, &data,
+				  &xpp, &xecfg))
+			die("unable to generate checkdiff for %s", one->path);
 
 		if (data.ws_rule & WS_BLANK_AT_EOF) {
 			struct emit_callback ecbdata;
@@ -4425,8 +4429,10 @@ static int diff_get_patch_id(struct diff_options *options, unsigned char *sha1)
 		xpp.flags = 0;
 		xecfg.ctxlen = 3;
 		xecfg.flags = 0;
-		xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
-			      &xpp, &xecfg);
+		if (xdi_diff_outf(&mf1, &mf2, patch_id_consume, &data,
+				  &xpp, &xecfg))
+			return error("unable to generate patch-id diff for %s",
+				     p->one->path);
 	}
 
 	git_SHA1_Final(sha1, &ctx);
diff --git a/diffcore-pickaxe.c b/diffcore-pickaxe.c
index 185f86b28..7715c13ec 100644
--- a/diffcore-pickaxe.c
+++ b/diffcore-pickaxe.c
@@ -62,8 +62,8 @@ static int diff_grep(mmfile_t *one, mmfile_t *two,
 	ecbdata.hit = 0;
 	xecfg.ctxlen = o->context;
 	xecfg.interhunkctxlen = o->interhunkcontext;
-	xdi_diff_outf(one, two, diffgrep_consume, &ecbdata,
-		      &xpp, &xecfg);
+	if (xdi_diff_outf(one, two, diffgrep_consume, &ecbdata, &xpp, &xecfg))
+		return 0;
 	return ecbdata.hit;
 }
 
diff --git a/line-log.c b/line-log.c
index 1a6bc5921..d4e29a574 100644
--- a/line-log.c
+++ b/line-log.c
@@ -325,7 +325,7 @@ static int collect_diff_cb(long start_a, long count_a,
 	return 0;
 }
 
-static void collect_diff(mmfile_t *parent, mmfile_t *target, struct diff_ranges *out)
+static int collect_diff(mmfile_t *parent, mmfile_t *target, struct diff_ranges *out)
 {
 	struct collect_diff_cbdata cbdata = {NULL};
 	xpparam_t xpp;
@@ -340,7 +340,7 @@ static void collect_diff(mmfile_t *parent, mmfile_t *target, struct diff_ranges
 	xecfg.hunk_func = collect_diff_cb;
 	memset(&ecb, 0, sizeof(ecb));
 	ecb.priv = &cbdata;
-	xdi_diff(parent, target, &xpp, &xecfg, &ecb);
+	return xdi_diff(parent, target, &xpp, &xecfg, &ecb);
 }
 
 /*
@@ -1030,7 +1030,8 @@ static int process_diff_filepair(struct rev_info *rev,
 	}
 
 	diff_ranges_init(&diff);
-	collect_diff(&file_parent, &file_target, &diff);
+	if (collect_diff(&file_parent, &file_target, &diff))
+		die("unable to generate diff for %s", pair->one->path);
 
 	/* NEEDSWORK should apply some heuristics to prevent mismatches */
 	free(rg->path);
diff --git a/ll-merge.c b/ll-merge.c
index 8ea03e536..4e789f533 100644
--- a/ll-merge.c
+++ b/ll-merge.c
@@ -88,7 +88,10 @@ static int ll_xdl_merge(const struct ll_merge_driver *drv_unused,
 	xmparam_t xmp;
 	assert(opts);
 
-	if (buffer_is_binary(orig->ptr, orig->size) ||
+	if (orig->size > MAX_XDIFF_SIZE ||
+	    src1->size > MAX_XDIFF_SIZE ||
+	    src2->size > MAX_XDIFF_SIZE ||
+	    buffer_is_binary(orig->ptr, orig->size) ||
 	    buffer_is_binary(src1->ptr, src1->size) ||
 	    buffer_is_binary(src2->ptr, src2->size)) {
 		return ll_binary_merge(drv_unused, result,
diff --git a/xdiff-interface.c b/xdiff-interface.c
index ecfa05f61..cb67c1c42 100644
--- a/xdiff-interface.c
+++ b/xdiff-interface.c
@@ -131,6 +131,9 @@ int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t co
 	mmfile_t a = *mf1;
 	mmfile_t b = *mf2;
 
+	if (mf1->size > MAX_XDIFF_SIZE || mf2->size > MAX_XDIFF_SIZE)
+		return -1;
+
 	trim_common_tail(&a, &b, xecfg->ctxlen);
 
 	return xdl_diff(&a, &b, xpp, xecfg, xecb);
diff --git a/xdiff-interface.h b/xdiff-interface.h
index eff7762ee..fbb5a1c39 100644
--- a/xdiff-interface.h
+++ b/xdiff-interface.h
@@ -3,6 +3,13 @@
 
 #include "xdiff/xdiff.h"
 
+/*
+ * xdiff isn't equipped to handle content over a gigabyte;
+ * we make the cutoff 1GB - 1MB to give some breathing
+ * room for constant-sized additions (e.g., merge markers)
+ */
+#define MAX_XDIFF_SIZE (1024UL * 1024 * 1023)
+
 typedef void (*xdiff_emit_consume_fn)(void *, char *, unsigned long);
 
 int xdi_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp, xdemitconf_t const *xecfg, xdemitcb_t *ecb);