From: Niels Möller <nisse@lysator.liu.se>
Date: Sat, 8 Nov 2025 14:59:31 +0000 (+0100)
Subject: Document changes to base16_decode_update and base64_decode_update.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=94ca2933c8516899eebba8fcce0731bc6d513e0c;p=thirdparty%2Fnettle.git

Document changes to base16_decode_update and base64_decode_update.
---

diff --git a/NEWS b/NEWS
index 438b135a..8b6d095a 100644
--- a/NEWS
+++ b/NEWS
@@ -50,6 +50,14 @@ NEWS for the Nettle 4.0 release
 	  sha3_256_ctx and sha3_256_init, are defined as preprocessor
 	  aliases, for backwards compatibility.
 
+	* The dst_length argument to base16_decode_update and
+	  base64_decode_update is now both an input and output
+	  argument. On input it must now hold the size of the
+	  destination buffer, and decoding fails if that is not
+	  sufficient. Previously, dst_length was an output only, and
+	  it was required that the destination buffer was large enough
+	  for any input of the given src_length.
+
 	Interface deletions:
 
 	* Deleted the old struct aes_ctx, and all functions operating
diff --git a/nettle.texinfo b/nettle.texinfo
index 212ba9be..7f61a5c1 100644
--- a/nettle.texinfo
+++ b/nettle.texinfo
@@ -6342,10 +6342,12 @@ to @code{base64_decode_update}.
 
 @deftypefun {void} base64_decode_update (struct base64_decode_ctx *@var{ctx}, size_t *@var{dst_length}, uint8_t *@var{dst}, size_t @var{src_length}, const uint8_t *@var{src})
 After @var{ctx} is initialized, this function may be called to decode
-@var{src_length} bytes from @var{src}. @var{dst} should point to an area
-of size at least BASE64_DECODE_LENGTH(@var{src_length}). The amount of data
-generated is returned in *@var{dst_length}. Returns 1 on success
-and 0 on error.
+@var{src_length} bytes from @var{src}. The buffer pointed to by
+@var{dst} must be of size *@var{dst_length}, and the amount of data
+actually generated is returned in *@var{dst_length}. Fails if
+@var{dst_length} is too small; using a buffer of size
+BASE64_DECODE_LENGTH(@var{src_length}) is always sufficient. Returns 1 on
+success and 0 on error.
 @end deftypefun
 
 @deftypefun {int} base64_decode_final (struct base64_decode_ctx *@var{ctx})
@@ -6389,10 +6391,12 @@ to @code{base16_decode_update}.
 
 @deftypefun {int} base16_decode_update (struct base16_decode_ctx *@var{ctx}, size_t *@var{dst_length}, uint8_t *@var{dst}, size_t @var{src_length}, const uint8_t *@var{src})
 After @var{ctx} is initialized, this function may be called to decode
-@var{src_length} bytes from @var{src}. @var{dst} should point to an area
-of size at least BASE16_DECODE_LENGTH(@var{src_length}). The amount of data
-generated is returned in *@var{dst_length}. Returns 1 on success
-and 0 on error.
+@var{src_length} bytes from @var{src}. The buffer pointed to by
+@var{dst} must be of size *@var{dst_length}, and the amount of data
+actually generated is returned in *@var{dst_length}. Fails if
+@var{dst_length} is too small; using a buffer of size
+BASE16_DECODE_LENGTH(@var{src_length}) is always sufficient. Returns 1 on
+success and 0 on error.
 @end deftypefun
 
 @deftypefun {int} base16_decode_final (struct base16_decode_ctx *@var{ctx})