shared.c: avoid SEGFAULT when checking for binary buffers

Before calling buffer_is_binary() we need to verify that the buffer
is valid.

Signed-off-by: Lars Hjemli <hjemli@gmail.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/shared.c b/shared.c
index dbb84d8..cce0af4 100644
--- a/shared.c
+++ b/shared.c
@@ -210,130 +210,130 @@ static int load_mmfile(mmfile_t *file, const unsigned char *sha1)
 	}
 	return 1;
 }
 
 /*
  * Receive diff-buffers from xdiff and concatenate them as
  * needed across multiple callbacks.
  *
  * This is basically a copy of xdiff-interface.c/xdiff_outf(),
  * ripped from git and modified to use globals instead of
  * a special callback-struct.
  */
 char *diffbuf = NULL;
 int buflen = 0;
 
 int filediff_cb(void *priv, mmbuffer_t *mb, int nbuf)
 {
 	int i;
 
 	for (i = 0; i < nbuf; i++) {
 		if (mb[i].ptr[mb[i].size-1] != '\n') {
 			/* Incomplete line */
 			diffbuf = xrealloc(diffbuf, buflen + mb[i].size);
 			memcpy(diffbuf + buflen, mb[i].ptr, mb[i].size);
 			buflen += mb[i].size;
 			continue;
 		}
 
 		/* we have a complete line */
 		if (!diffbuf) {
 			((linediff_fn)priv)(mb[i].ptr, mb[i].size);
 			continue;
 		}
 		diffbuf = xrealloc(diffbuf, buflen + mb[i].size);
 		memcpy(diffbuf + buflen, mb[i].ptr, mb[i].size);
 		((linediff_fn)priv)(diffbuf, buflen + mb[i].size);
 		free(diffbuf);
 		diffbuf = NULL;
 		buflen = 0;
 	}
 	if (diffbuf) {
 		((linediff_fn)priv)(diffbuf, buflen);
 		free(diffbuf);
 		diffbuf = NULL;
 		buflen = 0;
 	}
 	return 0;
 }
 
 int cgit_diff_files(const unsigned char *old_sha1,
 		    const unsigned char *new_sha1, unsigned long *old_size,
 		    unsigned long *new_size, int *binary, linediff_fn fn)
 {
 	mmfile_t file1, file2;
 	xpparam_t diff_params;
 	xdemitconf_t emit_params;
 	xdemitcb_t emit_cb;
 
 	if (!load_mmfile(&file1, old_sha1) || !load_mmfile(&file2, new_sha1))
 		return 1;
 
 	*old_size = file1.size;
 	*new_size = file2.size;
 
-	if (buffer_is_binary(file1.ptr, file1.size) ||
-	    buffer_is_binary(file2.ptr, file2.size)) {
+	if ((file1.ptr && buffer_is_binary(file1.ptr, file1.size)) ||
+	    (file2.ptr && buffer_is_binary(file2.ptr, file2.size))) {
 		*binary = 1;
 		return 0;
 	}
 
 	memset(&diff_params, 0, sizeof(diff_params));
 	memset(&emit_params, 0, sizeof(emit_params));
 	memset(&emit_cb, 0, sizeof(emit_cb));
 	diff_params.flags = XDF_NEED_MINIMAL;
 	emit_params.ctxlen = 3;
 	emit_params.flags = XDL_EMIT_FUNCNAMES;
 	emit_cb.outf = filediff_cb;
 	emit_cb.priv = fn;
 	xdl_diff(&file1, &file2, &diff_params, &emit_params, &emit_cb);
 	return 0;
 }
 
 void cgit_diff_tree(const unsigned char *old_sha1,
 		    const unsigned char *new_sha1,
 		    filepair_fn fn, const char *prefix)
 {
 	struct diff_options opt;
 	int ret;
 	int prefixlen;
 
 	diff_setup(&opt);
 	opt.output_format = DIFF_FORMAT_CALLBACK;
 	opt.detect_rename = 1;
 	opt.rename_limit = ctx.cfg.renamelimit;
 	DIFF_OPT_SET(&opt, RECURSIVE);
 	opt.format_callback = cgit_diff_tree_cb;
 	opt.format_callback_data = fn;
 	if (prefix) {
 		opt.nr_paths = 1;
 		opt.paths = &prefix;
 		prefixlen = strlen(prefix);
 		opt.pathlens = &prefixlen;
 	}
 	diff_setup_done(&opt);
 
 	if (old_sha1 && !is_null_sha1(old_sha1))
 		ret = diff_tree_sha1(old_sha1, new_sha1, "", &opt);
 	else
 		ret = diff_root_tree_sha1(new_sha1, "", &opt);
 	diffcore_std(&opt);
 	diff_flush(&opt);
 }
 
 void cgit_diff_commit(struct commit *commit, filepair_fn fn)
 {
 	unsigned char *old_sha1 = NULL;
 
 	if (commit->parents)
 		old_sha1 = commit->parents->item->object.sha1;
 	cgit_diff_tree(old_sha1, commit->object.sha1, fn, NULL);
 }
 
 int cgit_parse_snapshots_mask(const char *str)
 {
 	const struct cgit_snapshot_format *f;
 	static const char *delim = " \t,:/|;";
 	int tl, sl, rv = 0;
 
 	/* favor legacy setting */
 	if(atoi(str))