Avoid redefining constants introduced in glibc 2.41.

These constants are now available through <sys/auxv.h> when using
glibc >= 2.41, so we get re-define compilation errors.
Just rename them by prefixing them with "CRYPTO_" to avoid the
collision.

Change-Id: I61807d8dfc8b5f482ec6191cb41aebfa5676c5b6
Reviewed-on: https://boringssl-review.googlesource.com/c/boringssl/+/78527
Commit-Queue: David Benjamin <davidben@google.com>
Reviewed-by: David Benjamin <davidben@google.com>
Reviewed-by: Adam Langley <agl@google.com>

crypto/cpu_arm_linux.cc

diff --git a/crypto/cpu_arm_linux.cc b/crypto/cpu_arm_linux.cc
index 42ceecd..90489f7 100644
--- a/crypto/cpu_arm_linux.cc
+++ b/crypto/cpu_arm_linux.cc
@@ -109,7 +109,11 @@
 
   // Matching OpenSSL, only report other features if NEON is present.
   unsigned long hwcap = getauxval(AT_HWCAP);
-  if (hwcap & HWCAP_NEON) {
+  if (hwcap & CRYPTO_HWCAP_NEON) {
+#if defined(HWCAP_ARM_NEON)
+      static_assert(HWCAP_ARM_NEON == CRYPTO_HWCAP_NEON,
+                    "CRYPTO_HWCAP values must match Linux");
+#endif
     OPENSSL_armcap_P |= ARMV7_NEON;
 
     // Some ARMv8 Android devices don't expose AT_HWCAP2. Fall back to
@@ -123,16 +127,35 @@
       g_needs_hwcap2_workaround = hwcap2 != 0;
     }
 
-    if (hwcap2 & HWCAP2_AES) {
+    // HWCAP2_* values, without the "CRYPTO_" prefix, are exposed through
+    // <sys/auxv.h> in some versions of glibc(>= 2.41). Assert that we don't
+    // diverge from those values.
+    if (hwcap2 & CRYPTO_HWCAP2_AES) {
+#if defined(HWCAP2_AES)
+      static_assert(HWCAP2_AES == CRYPTO_HWCAP2_AES,
+                    "CRYPTO_HWCAP2 values must match Linux");
+#endif
       OPENSSL_armcap_P |= ARMV8_AES;
     }
-    if (hwcap2 & HWCAP2_PMULL) {
+    if (hwcap2 & CRYPTO_HWCAP2_PMULL) {
+#if defined(HWCAP2_PMULL)
+      static_assert(HWCAP2_PMULL == CRYPTO_HWCAP2_PMULL,
+                    "CRYPTO_HWCAP2 values must match Linux");
+#endif
       OPENSSL_armcap_P |= ARMV8_PMULL;
     }
-    if (hwcap2 & HWCAP2_SHA1) {
+    if (hwcap2 & CRYPTO_HWCAP2_SHA1) {
+#if defined(HWCAP2_SHA1)
+      static_assert(HWCAP2_SHA1 == CRYPTO_HWCAP2_SHA1,
+                    "CRYPTO_HWCAP2 values must match Linux");
+#endif
       OPENSSL_armcap_P |= ARMV8_SHA1;
     }
-    if (hwcap2 & HWCAP2_SHA2) {
+    if (hwcap2 & CRYPTO_HWCAP2_SHA2) {
+#if defined(HWCAP2_SHA2)
+      static_assert(HWCAP2_SHA2 == CRYPTO_HWCAP2_SHA2,
+                    "CRYPTO_HWCAP2 values must match Linux");
+#endif
       OPENSSL_armcap_P |= ARMV8_SHA256;
     }
   }

crypto/cpu_arm_linux.h

diff --git a/crypto/cpu_arm_linux.h b/crypto/cpu_arm_linux.h
index 81e37cb..196f3dd 100644
--- a/crypto/cpu_arm_linux.h
+++ b/crypto/cpu_arm_linux.h
@@ -29,14 +29,16 @@
 // The cpuinfo parser lives in a header file so it may be accessible from
 // cross-platform fuzzers without adding code to those platforms normally.
 
-#define HWCAP_NEON (1 << 12)
+#define CRYPTO_HWCAP_NEON (1 << 12)
 
 // See /usr/include/asm/hwcap.h on an ARM installation for the source of
 // these values.
-#define HWCAP2_AES (1 << 0)
-#define HWCAP2_PMULL (1 << 1)
-#define HWCAP2_SHA1 (1 << 2)
-#define HWCAP2_SHA2 (1 << 3)
+// We add the prefix "CRYPTO_" to the definitions so as not to collide with
+// some versions of glibc (>= 2.41) that expose them through <sys/auxv.h>.
+#define CRYPTO_HWCAP2_AES (1 << 0)
+#define CRYPTO_HWCAP2_PMULL (1 << 1)
+#define CRYPTO_HWCAP2_SHA1 (1 << 2)
+#define CRYPTO_HWCAP2_SHA2 (1 << 3)
 
 typedef struct {
   const char *data;
@@ -141,16 +143,16 @@
 
   unsigned long ret = 0;
   if (has_list_item(&features, "aes")) {
-    ret |= HWCAP2_AES;
+    ret |= CRYPTO_HWCAP2_AES;
   }
   if (has_list_item(&features, "pmull")) {
-    ret |= HWCAP2_PMULL;
+    ret |= CRYPTO_HWCAP2_PMULL;
   }
   if (has_list_item(&features, "sha1")) {
-    ret |= HWCAP2_SHA1;
+    ret |= CRYPTO_HWCAP2_SHA1;
   }
   if (has_list_item(&features, "sha2")) {
-    ret |= HWCAP2_SHA2;
+    ret |= CRYPTO_HWCAP2_SHA2;
   }
   return ret;
 }

crypto/cpu_arm_linux_test.cc

diff --git a/crypto/cpu_arm_linux_test.cc b/crypto/cpu_arm_linux_test.cc
index 7c91122..e301ccd 100644
--- a/crypto/cpu_arm_linux_test.cc
+++ b/crypto/cpu_arm_linux_test.cc
@@ -95,7 +95,8 @@
           // (Extra processors omitted.)
           "\n"
           "Hardware        : Qualcomm Technologies, Inc MSM8998\n",
-          HWCAP2_AES | HWCAP2_PMULL | HWCAP2_SHA1 | HWCAP2_SHA2,
+          CRYPTO_HWCAP2_AES | CRYPTO_HWCAP2_PMULL | CRYPTO_HWCAP2_SHA1 |
+              CRYPTO_HWCAP2_SHA2,
       },
       // Garbage should be tolerated.
       {
@@ -107,23 +108,24 @@
       {
           "Features        : aes pmull sha1 sha2\n"
           "CPU architecture: 8\n",
-          HWCAP2_AES | HWCAP2_PMULL | HWCAP2_SHA1 | HWCAP2_SHA2,
+          CRYPTO_HWCAP2_AES | CRYPTO_HWCAP2_PMULL | CRYPTO_HWCAP2_SHA1 |
+              CRYPTO_HWCAP2_SHA2,
       },
       // Various combinations of ARMv8 flags.
       {
           "Features        : aes sha1 sha2\n"
           "CPU architecture: 8\n",
-          HWCAP2_AES | HWCAP2_SHA1 | HWCAP2_SHA2,
+          CRYPTO_HWCAP2_AES | CRYPTO_HWCAP2_SHA1 | CRYPTO_HWCAP2_SHA2,
       },
       {
           "Features        : pmull sha2\n"
           "CPU architecture: 8\n",
-          HWCAP2_PMULL | HWCAP2_SHA2,
+          CRYPTO_HWCAP2_PMULL | CRYPTO_HWCAP2_SHA2,
       },
       {
           "Features        : aes aes   aes not_aes aes aes \n"
           "CPU architecture: 8\n",
-          HWCAP2_AES,
+          CRYPTO_HWCAP2_AES,
       },
       {
           "Features        : \n"