From 0681744528f395b0263a8bd54ed146412d260a04 Mon Sep 17 00:00:00 2001
From: Frank Denis <github@pureftpd.org>
Date: Wed, 8 Apr 2026 23:12:07 +0200
Subject: [PATCH] Call sodium_misuse on ridiculously high base64 input lengths

---
 src/libsodium/include/sodium/utils.h | 17 ++++++++++++-----
 src/libsodium/sodium/codecs.c        |  6 ++++++
 2 files changed, 18 insertions(+), 5 deletions(-)

diff --git a/src/libsodium/include/sodium/utils.h b/src/libsodium/include/sodium/utils.h
index e3c34800..626d4bd7 100644
--- a/src/libsodium/include/sodium/utils.h
+++ b/src/libsodium/include/sodium/utils.h
@@ -2,7 +2,9 @@
 #ifndef sodium_utils_H
 #define sodium_utils_H
 
+#include <limits.h>
 #include <stddef.h>
+#include <stdint.h>
 
 #include "export.h"
 
@@ -74,11 +76,16 @@ int sodium_hex2bin(unsigned char *const bin, const size_t bin_maxlen, const char
  * Computes the required length to encode BIN_LEN bytes as a base64 string
  * using the given variant. The computed length includes a trailing \0.
  */
-#define sodium_base64_ENCODED_LEN(BIN_LEN, VARIANT)                                              \
-    (((BIN_LEN) / 3U) * 4U +                                                                     \
-     ((((BIN_LEN) - ((BIN_LEN) / 3U) * 3U) | (((BIN_LEN) - ((BIN_LEN) / 3U) * 3U) >> 1)) & 1U) * \
-         (4U - ((0U - (((VARIANT) & 2U) >> 1)) & (3U - ((BIN_LEN) - ((BIN_LEN) / 3U) * 3U)))) + \
-     1U)
+#define sodium_base64_ENCODED_LEN(BIN_LEN, VARIANT)                            \
+  ((BIN_LEN) / 3U > (SIZE_MAX - 5) / 4U                                        \
+       ? (size_t)SIZE_MAX                                                      \
+       : (((BIN_LEN) / 3U) * 4U +                                              \
+          ((((BIN_LEN) - ((BIN_LEN) / 3U) * 3U) |                              \
+            (((BIN_LEN) - ((BIN_LEN) / 3U) * 3U) >> 1)) &                      \
+           1U) *                                                               \
+              (4U - ((0U - (((VARIANT) & 2U) >> 1)) &                          \
+                     (3U - ((BIN_LEN) - ((BIN_LEN) / 3U) * 3U)))) +            \
+          1U))
 
 SODIUM_EXPORT
 size_t sodium_base64_encoded_len(const size_t bin_len, const int variant);
diff --git a/src/libsodium/sodium/codecs.c b/src/libsodium/sodium/codecs.c
index f37f0e90..6a65244c 100644
--- a/src/libsodium/sodium/codecs.c
+++ b/src/libsodium/sodium/codecs.c
@@ -175,6 +175,9 @@ sodium_base64_encoded_len(const size_t bin_len, const int variant)
 {
     sodium_base64_check_variant(variant);
 
+    if (bin_len / 3 > (SIZE_MAX - 5) / 4) {
+      sodium_misuse(); /* LCOV_EXCL_LINE */
+    }
     return sodium_base64_ENCODED_LEN(bin_len, variant);
 }
 
@@ -193,6 +196,9 @@ sodium_bin2base64(char * const b64, const size_t b64_maxlen,
 
     sodium_base64_check_variant(variant);
     nibbles = bin_len / 3;
+    if (nibbles > (SIZE_MAX - 5) / 4) {
+        sodium_misuse(); /* LCOV_EXCL_LINE */
+    }
     remainder = bin_len - 3 * nibbles;
     b64_len = nibbles * 4;
     if (remainder != 0) {