From f75a6d951a95d6eea68b5ec6ca564fc8edaf1d14 Mon Sep 17 00:00:00 2001
From: Eugene Syromiatnikov <esyr@openssl.org>
Date: Thu, 28 Aug 2025 15:55:29 +0200
Subject: [PATCH] crypto/mem.c: use open-coded aligned alloc when
 posix_memalign fails
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While posix_memalign() is generally not expected to fail, we can always use
the internal aligned alloc implementation to ensure that any
OPENSSL_aligned_malloc failure is indeed fatal and does not require
a fallback.

Signed-off-by: Eugene Syromiatnikov <esyr@openssl.org>

Reviewed-by: Neil Horman <nhorman@openssl.org>
Reviewed-by: Saša Nedvědický <sashan@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/28295)
---
 crypto/mem.c          | 16 +++-------------
 test/mem_alloc_test.c | 15 +++------------
 2 files changed, 6 insertions(+), 25 deletions(-)

diff --git a/crypto/mem.c b/crypto/mem.c
index 985359a6813..681cecfadfd 100644
--- a/crypto/mem.c
+++ b/crypto/mem.c
@@ -242,26 +242,16 @@ void *CRYPTO_aligned_alloc(size_t num, size_t alignment, void **freeptr,
     /* Allow non-malloc() allocations as long as no malloc_impl is provided. */
     if (malloc_impl == CRYPTO_malloc) {
 #if defined(_BSD_SOURCE) || (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)
-        int memalign_ret;
         void *ret;
 
         /* posix_memalign() requires alignment to be at least sizeof(void *) */
         if (alignment < sizeof(void *))
             alignment = sizeof(void *);
 
-        if ((memalign_ret = posix_memalign(&ret, alignment, num))) {
-            ret = NULL;
-            switch (memalign_ret) {
-            case EINVAL:
-                ossl_report_alloc_err_inv(file, line);
-                break;
-            case ENOMEM:
-                ossl_report_alloc_err(file, line);
-                break;
-            }
+        if (posix_memalign(&ret, alignment, num) == 0) {
+            *freeptr = ret;
+            return ret;
         }
-        *freeptr = ret;
-        return ret;
 #endif
     }
 
diff --git a/test/mem_alloc_test.c b/test/mem_alloc_test.c
index 2571c4eceb7..30c479cd80a 100644
--- a/test/mem_alloc_test.c
+++ b/test/mem_alloc_test.c
@@ -176,19 +176,10 @@ static const struct array_aligned_alloc_vector {
     { SIZE_MAX / 8 + 9, 8, 64, EXP_NONNULL, EXP_INT_OF },
 
     /*
-     * posix_memalign expected to fail with ENOMEM, while the open-coded
-     * implementation tries to alloc size + alignment, which should fail
-     * on integer overflow.
+     * the open-coded implementation tries to alloc size + alignment,
+     * which should fail on integer overflow.
      */
-    { 1, SIZE_MAX / 2 + 2, SIZE_MAX / 2 + 1,
-#if (defined(_BSD_SOURCE) \
-      || (defined(_POSIX_C_SOURCE) && _POSIX_C_SOURCE >= 200112L)) \
-    && !USE_CUSTOM_ALLOC_FNS
-      EXP_OOM, EXP_OOM
-#else
-      EXP_INT_OF, EXP_INT_OF
-#endif
-    },
+    { 1, SIZE_MAX - 32767, 65536, EXP_INT_OF, EXP_INT_OF },
 };
 
 static int secure_memory_is_secure;
-- 
2.47.3