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
@@ -250,50 +250,50 @@ int filediff_cb(void *priv, mmbuffer_t *mb, int nbuf)
 	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;