From: Collin Funk <collin.funk1@gmail.com>
Date: Wed, 3 Sep 2025 02:16:17 +0000 (-0700)
Subject: crypto/sha3-buffer: Don't abort on OOM.
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=06e7da510bd055f524c1baff0890c861bef2b6a4;p=thirdparty%2Fgnulib.git

crypto/sha3-buffer: Don't abort on OOM.

* modules/crypto/sha3-buffer (Depends-on): Add stddef-h.
* lib/sha3.h: Include stddef.h.
(sha3_ctx): Use a stack allocated buffer used to cast to store an
EVP_MD_CTX.
* lib/sha3.c (DEFINE_SHA3_INIT_CTX): Initialize the structure to zero.
Use the stack allocated buffer instead of calling EVP_MD_CTX_create.
(sha3_read_ctx): Just call sha3_finish_ctx similar to the other crypto
modules.
(sha3_finish_ctx): Remove call to EVP_MD_CTX_free. Call
EVP_DigestFinal_ex.
---

diff --git a/ChangeLog b/ChangeLog
index a016eec8f0..3752bb9198 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,17 @@
 2025-09-03  Collin Funk  <collin.funk1@gmail.com>
 
+	crypto/sha3-buffer: Don't abort on OOM.
+	* modules/crypto/sha3-buffer (Depends-on): Add stddef-h.
+	* lib/sha3.h: Include stddef.h.
+	(sha3_ctx): Use a stack allocated buffer used to cast to store an
+	EVP_MD_CTX.
+	* lib/sha3.c (DEFINE_SHA3_INIT_CTX): Initialize the structure to zero.
+	Use the stack allocated buffer instead of calling EVP_MD_CTX_create.
+	(sha3_read_ctx): Just call sha3_finish_ctx similar to the other crypto
+	modules.
+	(sha3_finish_ctx): Remove call to EVP_MD_CTX_free. Call
+	EVP_DigestFinal_ex.
+
 	gnulib-tool: Avoid Automake error when using --create-testdir (regr. today).
 	* gnulib-tool.sh (func_emit_tests_Makefile_am): Initialize AM_CFLAGS and
 	AM_CXXFLAGS when creating a test directory.
diff --git a/lib/sha3.c b/lib/sha3.c
index 5da85db5f2..e30210fb3e 100644
--- a/lib/sha3.c
+++ b/lib/sha3.c
@@ -323,11 +323,11 @@ sha3_process_block (const void *buffer, size_t len, struct sha3_ctx *ctx)
   void                                                                  \
   sha3_##SIZE##_init_ctx (struct sha3_ctx *ctx)                         \
   {                                                                     \
-    int rc;                                                             \
-    ctx->evp_ctx = EVP_MD_CTX_create ();                                \
-    if (ctx->evp_ctx == NULL)                                           \
-      abort ();                                                         \
-    rc = EVP_DigestInit_ex (ctx->evp_ctx, EVP_sha3_##SIZE (), NULL);    \
+    /* EVP_DigestInit_ex expects all bytes to be zero.  */              \
+    memset (ctx, 0, sizeof *ctx);                                       \
+    EVP_MD_CTX *evp_ctx = (EVP_MD_CTX *) ctx->evp_ctx_buffer;           \
+    int rc = EVP_DigestInit_ex (evp_ctx, EVP_sha3_##SIZE (), NULL);     \
+    /* This should never fail.  */                                      \
     if (rc == 0)                                                        \
       abort ();                                                         \
   }
@@ -341,17 +341,17 @@ void *
 sha3_read_ctx (const struct sha3_ctx *ctx, void *resbuf)
 {
   /* Assume any unprocessed bytes in ctx are not to be ignored.  */
-  int result = EVP_DigestFinal_ex (ctx->evp_ctx, resbuf, NULL);
-  if (result == 0)
-    abort ();
-  return resbuf;
+  return sha3_finish_ctx ((struct sha3_ctx *) ctx, resbuf);
 }
 
 void *
 sha3_finish_ctx (struct sha3_ctx *ctx, void *resbuf)
 {
-  void *result = sha3_read_ctx (ctx, resbuf);
-  EVP_MD_CTX_free (ctx->evp_ctx);
+  EVP_MD_CTX *evp_ctx = (EVP_MD_CTX *) ctx->evp_ctx_buffer;
+  /* This should never fail.  */
+  int result = EVP_DigestFinal_ex (evp_ctx, resbuf, NULL);
+  if (result == 0)
+    abort ();
   return resbuf;
 }
 
@@ -373,7 +373,8 @@ DEFINE_SHA3_BUFFER (512)
 void
 sha3_process_bytes (const void *buffer, size_t len, struct sha3_ctx *ctx)
 {
-  int result = EVP_DigestUpdate (ctx->evp_ctx, buffer, len);
+  EVP_MD_CTX *evp_ctx = (EVP_MD_CTX *) ctx->evp_ctx_buffer;
+  int result = EVP_DigestUpdate (evp_ctx, buffer, len);
   if (result == 0)
     abort ();
 }
diff --git a/lib/sha3.h b/lib/sha3.h
index 7de1216fda..adce43eac7 100644
--- a/lib/sha3.h
+++ b/lib/sha3.h
@@ -19,6 +19,7 @@
 #ifndef SHA3_H
 # define SHA3_H 1
 
+# include <stddef.h>
 # include <stdio.h>
 # include <stdint.h>
 
@@ -50,9 +51,9 @@ enum { SHA3_512_BLOCK_SIZE = 576 / 8 };
 struct sha3_ctx
 {
 # if HAVE_OPENSSL_SHA3
-  /* This is an incomplete type, so we can only place a pointer in the
-     struct.  */
-  EVP_MD_CTX *evp_ctx;
+  /* EVP_MD_CTX is an incomplete type.  EVP_MD_CTX_create allocates 72 bytes of
+     memory as of 2025-09-02.  */
+  max_align_t evp_ctx_buffer[256 / sizeof (max_align_t)];
 # else
   u64 state[25];
   uint8_t buffer[144]; /* Up to BLOCKLEN in use.  */
diff --git a/modules/crypto/sha3-buffer b/modules/crypto/sha3-buffer
index 83b3a090ff..e0e654e563 100644
--- a/modules/crypto/sha3-buffer
+++ b/modules/crypto/sha3-buffer
@@ -10,6 +10,7 @@ m4/sha3.m4
 Depends-on:
 byteswap
 c99
+stddef-h
 stdint-h
 u64