InnoDB: Fix potential buffer underflow.

1 files changed, 24 insertions, 1 deletions

diff --git a/innobase/ut/ut0mem.c b/innobase/ut/ut0mem.c
index c1e3ebbf35c..47b1e24e5e1 100644
--- a/innobase/ut/ut0mem.c
+++ b/innobase/ut/ut0mem.c
@@ -364,7 +364,30 @@ ut_strlcpy(
 		dst[n] = '\0';
 	}
 
-	return src_size;
+	return(src_size);
+}
+
+/**************************************************************************
+Like ut_strlcpy, but if src doesn't fit in dst completely, copies the last
+(size - 1) bytes of src, not the first. */
+
+ulint
+ut_strlcpy_rev(
+/*===========*/
+				/* out: strlen(src) */
+	char*		dst,	/* in: destination buffer */
+	const char*	src,	/* in: source buffer */
+	ulint		size)	/* in: size of destination buffer */
+{
+	ulint	src_size = strlen(src);
+
+	if (size != 0) {
+		ulint	n = ut_min(src_size, size - 1);
+
+		memcpy(dst, src + src_size - n, n + 1);
+	}
+
+	return(src_size);
 }
 
 /**************************************************************************