diff --git a/include/common/chunk.h b/include/common/chunk.h
index a1a3eb779..18abca7bd 100644
--- a/include/common/chunk.h
+++ b/include/common/chunk.h
@@ -98,7 +98,7 @@ static inline void chunk_initstr(struct buffer *chk, const char *str)
 /* copies chunk <src> into <chk>. Returns 0 in case of failure. */
 static inline int chunk_cpy(struct buffer *chk, const struct buffer *src)
 {
-	if (unlikely(src->data >= chk->size))
+	if (unlikely(src->data > chk->size))
 		return 0;
 
 	chk->data  = src->data;
@@ -109,7 +109,7 @@ static inline int chunk_cpy(struct buffer *chk, const struct buffer *src)
 /* appends chunk <src> after <chk>. Returns 0 in case of failure. */
 static inline int chunk_cat(struct buffer *chk, const struct buffer *src)
 {
-	if (unlikely(chk->data + src->data >= chk->size))
+	if (unlikely(chk->data + src->data > chk->size))
 		return 0;
 
 	memcpy(chk->area + chk->data, src->area, src->data);
@@ -123,7 +123,7 @@ static inline int chunk_cat(struct buffer *chk, const struct buffer *src)
 static inline int chunk_memcpy(struct buffer *chk, const char *src,
 			       size_t len)
 {
-	if (unlikely(len >= chk->size))
+	if (unlikely(len > chk->size))
 		return 0;
 
 	chk->data  = len;
@@ -138,7 +138,7 @@ static inline int chunk_memcpy(struct buffer *chk, const char *src,
 static inline int chunk_memcat(struct buffer *chk, const char *src,
 			       size_t len)
 {
-	if (unlikely(chk->data + len >= chk->size))
+	if (unlikely(chk->data + len > chk->size))
 		return 0;
 
 	memcpy(chk->area + chk->data, src, len);