X-Git-Url: http://git.liburcu.org/?a=blobdiff_plain;f=libringbuffer%2Fring_buffer_backend.c;fp=libringbuffer%2Fring_buffer_backend.c;h=02c893d3d796544ad9722baf9246b391010831aa;hb=3ff6e388aad7e21dbbd556cbe1d53f1d6714534e;hp=ae8365227c3405fcb39aad8a32eba3e5d730be14;hpb=a3c3a9f70abbfba9aa524f44b2f1f52faf574402;p=lttng-ust.git

diff --git a/libringbuffer/ring_buffer_backend.c b/libringbuffer/ring_buffer_backend.c
index ae836522..02c893d3 100644
--- a/libringbuffer/ring_buffer_backend.c
+++ b/libringbuffer/ring_buffer_backend.c
@@ -379,8 +379,9 @@ size_t lib_ring_buffer_read(struct lttng_ust_lib_ring_buffer_backend *bufb, size
  * @dest : destination address
  * @len : destination's length
  *
- * return string's length
+ * Return string's length, or -EINVAL on error.
  * Should be protected by get_subbuf/put_subbuf.
+ * Destination length should be at least 1 to hold '\0'.
  */
 int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, size_t offset,
 			      void *dest, size_t len, struct lttng_ust_shm_handle *handle)
@@ -392,6 +393,8 @@ int lib_ring_buffer_read_cstr(struct lttng_ust_lib_ring_buffer_backend *bufb, si
 	struct lttng_ust_lib_ring_buffer_backend_pages_shmp *rpages;
 	unsigned long sb_bindex, id;
 
+	if (caa_unlikely(!len))
+		return -EINVAL;
 	offset &= chanb->buf_size - 1;
 	orig_offset = offset;
 	id = bufb->buf_rsb.id;