Detect Android LOKI'd boot bootimgs
buffer_fill: fix double free of `ebuf` on read error (https://bugzilla.redhat.com/1685217)

---
 magic/Magdir/android |    4 +++-
 src/buffer.c         |    1 +
 2 files changed, 4 insertions(+), 1 deletion(-)

--- magic/Magdir/android
+++ magic/Magdir/android	2019-06-11 10:34:41.940646113 +0000
@@ -19,7 +19,9 @@
 # From https://android.googlesource.com/\
 # platform/system/core/+/master/mkbootimg/bootimg.h
 0		string	ANDROID!	Android bootimg
->1024	string	LOKI\01		\b, LOKI'd
+>1024	string	LOKI		\b, LOKI'd
+>>1028	lelong	0			\b (boot)
+>>1028	lelong	1			\b (recovery)
 >8		lelong	>0			\b, kernel
 >>12	lelong	>0			\b (0x%x)
 >16		lelong	>0			\b, ramdisk
--- src/buffer.c
+++ src/buffer.c	2019-06-11 10:34:41.940646113 +0000
@@ -77,6 +77,7 @@ buffer_fill(const struct buffer *bb)
 	b->eoff = b->st.st_size - b->elen;
 	if (pread(b->fd, b->ebuf, b->elen, b->eoff) == -1) {
 		free(b->ebuf);
+		b->ebuf = NULL;
 		goto out;
 	}