30 files changed, 132 insertions, 110 deletions

diff --git a/src/lib/libcrypto/aes/asm/aes-x86_64.pl b/src/lib/libcrypto/aes/asm/aes-x86_64.pl
index 78ba20ca59..299214800b 100755
--- a/src/lib/libcrypto/aes/asm/aes-x86_64.pl
+++ b/src/lib/libcrypto/aes/asm/aes-x86_64.pl
@@ -318,7 +318,7 @@ $code.=<<___;
 .type   _x86_64_AES_encrypt,\@abi-omnipotent
 .align  16
 _x86_64_AES_encrypt:
-        endbr64
+        _CET_ENDBR
         xor     0($key),$s0                     # xor with key
         xor     4($key),$s1
         xor     8($key),$s2
@@ -549,7 +549,7 @@ $code.=<<___;
 .type   _x86_64_AES_encrypt_compact,\@abi-omnipotent
 .align  16
 _x86_64_AES_encrypt_compact:
-        endbr64
+        _CET_ENDBR
         lea     128($sbox),$inp                 # size optimization
         mov     0-128($inp),$acc1               # prefetch Te4
         mov     32-128($inp),$acc2
@@ -595,7 +595,7 @@ $code.=<<___;
 .hidden asm_AES_encrypt
 asm_AES_encrypt:
 AES_encrypt:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12
@@ -887,7 +887,7 @@ $code.=<<___;
 .type   _x86_64_AES_decrypt,\@abi-omnipotent
 .align  16
 _x86_64_AES_decrypt:
-        endbr64
+        _CET_ENDBR
         xor     0($key),$s0                     # xor with key
         xor     4($key),$s1
         xor     8($key),$s2
@@ -1142,7 +1142,7 @@ $code.=<<___;
 .type   _x86_64_AES_decrypt_compact,\@abi-omnipotent
 .align  16
 _x86_64_AES_decrypt_compact:
-        endbr64
+        _CET_ENDBR
         lea     128($sbox),$inp                 # size optimization
         mov     0-128($inp),$acc1               # prefetch Td4
         mov     32-128($inp),$acc2
@@ -1197,7 +1197,7 @@ $code.=<<___;
 .hidden asm_AES_decrypt
 asm_AES_decrypt:
 AES_decrypt:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12
@@ -1297,7 +1297,7 @@ $code.=<<___;
 .type   AES_set_encrypt_key,\@function,3
 .align  16
 AES_set_encrypt_key:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12                    # redundant, but allows to share 
@@ -1323,7 +1323,7 @@ AES_set_encrypt_key:
 .type   _x86_64_AES_set_encrypt_key,\@abi-omnipotent
 .align  16
 _x86_64_AES_set_encrypt_key:
-        endbr64
+        _CET_ENDBR
         mov     %esi,%ecx                       # %ecx=bits
         mov     %rdi,%rsi                       # %rsi=userKey
         mov     %rdx,%rdi                       # %rdi=key
@@ -1569,7 +1569,7 @@ $code.=<<___;
 .type   AES_set_decrypt_key,\@function,3
 .align  16
 AES_set_decrypt_key:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12
@@ -1669,7 +1669,7 @@ $code.=<<___;
 .hidden asm_AES_cbc_encrypt
 asm_AES_cbc_encrypt:
 AES_cbc_encrypt:
-        endbr64
+        _CET_ENDBR
         cmp     \$0,%rdx        # check length
         je      .Lcbc_epilogue
         pushfq
@@ -2561,7 +2561,7 @@ $code.=<<___;
 .type   block_se_handler,\@abi-omnipotent
 .align  16
 block_se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
@@ -2620,7 +2620,7 @@ block_se_handler:
 .type   key_se_handler,\@abi-omnipotent
 .align  16
 key_se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
@@ -2678,7 +2678,7 @@ key_se_handler:
 .type   cbc_se_handler,\@abi-omnipotent
 .align  16
 cbc_se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
diff --git a/src/lib/libcrypto/aes/asm/aesni-sha1-x86_64.pl b/src/lib/libcrypto/aes/asm/aesni-sha1-x86_64.pl
index 879d16793f..5eb5b7bf65 100644
--- a/src/lib/libcrypto/aes/asm/aesni-sha1-x86_64.pl
+++ b/src/lib/libcrypto/aes/asm/aesni-sha1-x86_64.pl
@@ -89,7 +89,7 @@ $code.=<<___;
 .type   aesni_cbc_sha1_enc,\@abi-omnipotent
 .align  16
 aesni_cbc_sha1_enc:
-        endbr64
+        _CET_ENDBR
         # caller should check for SSSE3 and AES-NI bits
         mov     OPENSSL_ia32cap_P+0(%rip),%r10d
         mov     OPENSSL_ia32cap_P+4(%rip),%r11d
@@ -133,7 +133,7 @@ $code.=<<___;
 .type   aesni_cbc_sha1_enc_ssse3,\@function,6
 .align  16
 aesni_cbc_sha1_enc_ssse3:
-        endbr64
+        _CET_ENDBR
         mov     `($win64?56:8)`(%rsp),$inp      # load 7th argument
         #shr    \$6,$len                        # debugging artefact
         #jz     .Lepilogue_ssse3                # debugging artefact
@@ -652,7 +652,7 @@ $code.=<<___;
 .type   aesni_cbc_sha1_enc_avx,\@function,6
 .align  16
 aesni_cbc_sha1_enc_avx:
-        endbr64
+        _CET_ENDBR
         mov     `($win64?56:8)`(%rsp),$inp      # load 7th argument
         #shr    \$6,$len                        # debugging artefact
         #jz     .Lepilogue_avx                  # debugging artefact
@@ -1103,7 +1103,7 @@ $code.=<<___;
 .type   ssse3_handler,\@abi-omnipotent
 .align  16
 ssse3_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
diff --git a/src/lib/libcrypto/aes/asm/aesni-x86_64.pl b/src/lib/libcrypto/aes/asm/aesni-x86_64.pl
index 07d40a84ab..43013a51fb 100644
--- a/src/lib/libcrypto/aes/asm/aesni-x86_64.pl
+++ b/src/lib/libcrypto/aes/asm/aesni-x86_64.pl
@@ -242,7 +242,7 @@ $code.=<<___;
 .type   ${PREFIX}_encrypt,\@abi-omnipotent
 .align  16
 ${PREFIX}_encrypt:
-        endbr64
+        _CET_ENDBR
         movups  ($inp),$inout0          # load input
         mov     240($key),$rounds       # key->rounds
 ___
@@ -256,7 +256,7 @@ $code.=<<___;
 .type   ${PREFIX}_decrypt,\@abi-omnipotent
 .align  16
 ${PREFIX}_decrypt:
-        endbr64
+        _CET_ENDBR
         movups  ($inp),$inout0          # load input
         mov     240($key),$rounds       # key->rounds
 ___
@@ -286,7 +286,7 @@ $code.=<<___;
 .type   _aesni_${dir}rypt3,\@abi-omnipotent
 .align  16
 _aesni_${dir}rypt3:
-        endbr64
+        _CET_ENDBR
         $movkey ($key),$rndkey0
         shr     \$1,$rounds
         $movkey 16($key),$rndkey1
@@ -331,7 +331,7 @@ $code.=<<___;
 .type   _aesni_${dir}rypt4,\@abi-omnipotent
 .align  16
 _aesni_${dir}rypt4:
-        endbr64
+        _CET_ENDBR
         $movkey ($key),$rndkey0
         shr     \$1,$rounds
         $movkey 16($key),$rndkey1
@@ -377,7 +377,7 @@ $code.=<<___;
 .type   _aesni_${dir}rypt6,\@abi-omnipotent
 .align  16
 _aesni_${dir}rypt6:
-        endbr64
+        _CET_ENDBR
         $movkey         ($key),$rndkey0
         shr             \$1,$rounds
         $movkey         16($key),$rndkey1
@@ -442,7 +442,7 @@ $code.=<<___;
 .type   _aesni_${dir}rypt8,\@abi-omnipotent
 .align  16
 _aesni_${dir}rypt8:
-        endbr64
+        _CET_ENDBR
         $movkey         ($key),$rndkey0
         shr             \$1,$rounds
         $movkey         16($key),$rndkey1
@@ -531,7 +531,7 @@ $code.=<<___;
 .type   aesni_ecb_encrypt,\@function,5
 .align  16
 aesni_ecb_encrypt:
-        endbr64
+        _CET_ENDBR
         and     \$-16,$len
         jz      .Lecb_ret
 
@@ -837,7 +837,7 @@ $code.=<<___;
 .type   aesni_ccm64_encrypt_blocks,\@function,6
 .align  16
 aesni_ccm64_encrypt_blocks:
-        endbr64
+        _CET_ENDBR
 ___
 $code.=<<___ if ($win64);
         lea     -0x58(%rsp),%rsp
@@ -1025,7 +1025,7 @@ $code.=<<___;
 .type   aesni_ctr32_encrypt_blocks,\@function,5
 .align  16
 aesni_ctr32_encrypt_blocks:
-        endbr64
+        _CET_ENDBR
         lea     (%rsp),%rax
         push    %rbp
         sub     \$$frame_size,%rsp
@@ -2487,7 +2487,7 @@ $code.=<<___;
 .type   ${PREFIX}_set_decrypt_key,\@abi-omnipotent
 .align  16
 ${PREFIX}_set_decrypt_key:
-        endbr64
+        _CET_ENDBR
         sub     \$8,%rsp
         call    __aesni_set_encrypt_key
         shl     \$4,$bits               # rounds-1 after _aesni_set_encrypt_key
@@ -2538,7 +2538,7 @@ $code.=<<___;
 .type   ${PREFIX}_set_encrypt_key,\@abi-omnipotent
 .align  16
 ${PREFIX}_set_encrypt_key:
-        endbr64
+        _CET_ENDBR
 __aesni_set_encrypt_key:
         sub     \$8,%rsp
         mov     \$-1,%rax
@@ -2760,7 +2760,7 @@ $code.=<<___ if ($PREFIX eq "aesni");
 .type   ecb_se_handler,\@abi-omnipotent
 .align  16
 ecb_se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
@@ -2780,7 +2780,7 @@ ecb_se_handler:
 .type   ccm64_se_handler,\@abi-omnipotent
 .align  16
 ccm64_se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
@@ -2822,7 +2822,7 @@ ccm64_se_handler:
 .type   ctr32_se_handler,\@abi-omnipotent
 .align  16
 ctr32_se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
@@ -2858,7 +2858,7 @@ ctr32_se_handler:
 .type   xts_se_handler,\@abi-omnipotent
 .align  16
 xts_se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
@@ -2900,7 +2900,7 @@ $code.=<<___;
 .type   cbc_se_handler,\@abi-omnipotent
 .align  16
 cbc_se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
diff --git a/src/lib/libcrypto/aes/asm/bsaes-x86_64.pl b/src/lib/libcrypto/aes/asm/bsaes-x86_64.pl
index 7098ba27f4..c44a338114 100644
--- a/src/lib/libcrypto/aes/asm/bsaes-x86_64.pl
+++ b/src/lib/libcrypto/aes/asm/bsaes-x86_64.pl
@@ -813,7 +813,7 @@ $code.=<<___;
 .type   _bsaes_encrypt8,\@abi-omnipotent
 .align  64
 _bsaes_encrypt8:
-        endbr64
+        _CET_ENDBR
         lea     .LBS0(%rip), $const     # constants table
 
         movdqa  ($key), @XMM[9]         # round 0 key
@@ -878,7 +878,7 @@ $code.=<<___;
 .type   _bsaes_decrypt8,\@abi-omnipotent
 .align  64
 _bsaes_decrypt8:
-        endbr64
+        _CET_ENDBR
         lea     .LBS0(%rip), $const     # constants table
 
         movdqa  ($key), @XMM[9]         # round 0 key
@@ -970,7 +970,7 @@ $code.=<<___;
 .type   _bsaes_key_convert,\@abi-omnipotent
 .align  16
 _bsaes_key_convert:
-        endbr64
+        _CET_ENDBR
         lea     .Lmasks(%rip), $const
         movdqu  ($inp), %xmm7           # load round 0 key
         lea     0x10($inp), $inp
@@ -1060,7 +1060,7 @@ $code.=<<___;
 .type   bsaes_enc_key_convert,\@function,2
 .align  16
 bsaes_enc_key_convert:
-        endbr64
+        _CET_ENDBR
         mov     240($inp),%r10d         # pass rounds
         mov     $inp,%rcx               # pass key
         mov     $out,%rax               # pass key schedule
@@ -1075,7 +1075,7 @@ bsaes_enc_key_convert:
 .align  16
 bsaes_encrypt_128:
 .Lenc128_loop:
-        endbr64
+        _CET_ENDBR
         movdqu  0x00($inp), @XMM[0]     # load input
         movdqu  0x10($inp), @XMM[1]
         movdqu  0x20($inp), @XMM[2]
@@ -1108,7 +1108,7 @@ bsaes_encrypt_128:
 .type   bsaes_dec_key_convert,\@function,2
 .align  16
 bsaes_dec_key_convert:
-        endbr64
+        _CET_ENDBR
         mov     240($inp),%r10d         # pass rounds
         mov     $inp,%rcx               # pass key
         mov     $out,%rax               # pass key schedule
@@ -1123,7 +1123,7 @@ bsaes_dec_key_convert:
 .type   bsaes_decrypt_128,\@function,4
 .align  16
 bsaes_decrypt_128:
-        endbr64
+        _CET_ENDBR
 .Ldec128_loop:
         movdqu  0x00($inp), @XMM[0]     # load input
         movdqu  0x10($inp), @XMM[1]
@@ -1169,7 +1169,7 @@ $code.=<<___;
 .type   bsaes_ecb_encrypt_blocks,\@abi-omnipotent
 .align  16
 bsaes_ecb_encrypt_blocks:
-        endbr64
+        _CET_ENDBR
         mov     %rsp, %rax
 .Lecb_enc_prologue:
         push    %rbp
@@ -1371,7 +1371,7 @@ $code.=<<___;
 .type   bsaes_ecb_decrypt_blocks,\@abi-omnipotent
 .align  16
 bsaes_ecb_decrypt_blocks:
-        endbr64
+        _CET_ENDBR
         mov     %rsp, %rax
 .Lecb_dec_prologue:
         push    %rbp
@@ -1577,7 +1577,7 @@ $code.=<<___;
 .type   bsaes_cbc_encrypt,\@abi-omnipotent
 .align  16
 bsaes_cbc_encrypt:
-        endbr64
+        _CET_ENDBR
 ___
 $code.=<<___ if ($win64);
         mov     48(%rsp),$arg6          # pull direction flag
@@ -1865,7 +1865,7 @@ $code.=<<___;
 .type   bsaes_ctr32_encrypt_blocks,\@abi-omnipotent
 .align  16
 bsaes_ctr32_encrypt_blocks:
-        endbr64
+        _CET_ENDBR
         mov     %rsp, %rax
 .Lctr_enc_prologue:
         push    %rbp
@@ -2107,7 +2107,7 @@ $code.=<<___;
 .type   bsaes_xts_encrypt,\@abi-omnipotent
 .align  16
 bsaes_xts_encrypt:
-        endbr64
+        _CET_ENDBR
         mov     %rsp, %rax
 .Lxts_enc_prologue:
         push    %rbp
@@ -2489,7 +2489,7 @@ $code.=<<___;
 .type   bsaes_xts_decrypt,\@abi-omnipotent
 .align  16
 bsaes_xts_decrypt:
-        endbr64
+        _CET_ENDBR
         mov     %rsp, %rax
 .Lxts_dec_prologue:
         push    %rbp
@@ -2966,7 +2966,7 @@ $code.=<<___;
 .type   se_handler,\@abi-omnipotent
 .align  16
 se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
diff --git a/src/lib/libcrypto/aes/asm/vpaes-x86_64.pl b/src/lib/libcrypto/aes/asm/vpaes-x86_64.pl
index 8ff8d8602b..7d92e8d8ca 100644
--- a/src/lib/libcrypto/aes/asm/vpaes-x86_64.pl
+++ b/src/lib/libcrypto/aes/asm/vpaes-x86_64.pl
@@ -82,7 +82,7 @@ $code.=<<___;
 .type   _vpaes_encrypt_core,\@abi-omnipotent
 .align 16
 _vpaes_encrypt_core:
-        endbr64
+        _CET_ENDBR
         mov     %rdx,   %r9
         mov     \$16,   %r11
         mov     240(%rdx),%eax
@@ -173,7 +173,7 @@ _vpaes_encrypt_core:
 .type   _vpaes_decrypt_core,\@abi-omnipotent
 .align  16
 _vpaes_decrypt_core:
-        endbr64
+        _CET_ENDBR
         mov     %rdx,   %r9             # load key
         mov     240(%rdx),%eax
         movdqa  %xmm9,  %xmm1
@@ -281,7 +281,7 @@ _vpaes_decrypt_core:
 .type   _vpaes_schedule_core,\@abi-omnipotent
 .align  16
 _vpaes_schedule_core:
-        endbr64
+        _CET_ENDBR
         # rdi = key
         # rsi = size in bits
         # rdx = buffer
@@ -467,7 +467,7 @@ _vpaes_schedule_core:
 .type   _vpaes_schedule_192_smear,\@abi-omnipotent
 .align  16
 _vpaes_schedule_192_smear:
-        endbr64
+        _CET_ENDBR
         pshufd  \$0x80, %xmm6,  %xmm0   # d c 0 0 -> c 0 0 0
         pxor    %xmm0,  %xmm6           # -> c+d c 0 0
         pshufd  \$0xFE, %xmm7,  %xmm0   # b a _ _ -> b b b a
@@ -499,7 +499,7 @@ _vpaes_schedule_192_smear:
 .type   _vpaes_schedule_round,\@abi-omnipotent
 .align  16
 _vpaes_schedule_round:
-        endbr64
+        _CET_ENDBR
         # extract rcon from xmm8
         pxor    %xmm1,  %xmm1
         palignr \$15,   %xmm8,  %xmm1
@@ -567,7 +567,7 @@ _vpaes_schedule_low_round:
 .type   _vpaes_schedule_transform,\@abi-omnipotent
 .align  16
 _vpaes_schedule_transform:
-        endbr64
+        _CET_ENDBR
         movdqa  %xmm9,  %xmm1
         pandn   %xmm0,  %xmm1
         psrld   \$4,    %xmm1
@@ -606,7 +606,7 @@ _vpaes_schedule_transform:
 .type   _vpaes_schedule_mangle,\@abi-omnipotent
 .align  16
 _vpaes_schedule_mangle:
-        endbr64
+        _CET_ENDBR
         movdqa  %xmm0,  %xmm4   # save xmm0 for later
         movdqa  .Lk_mc_forward(%rip),%xmm5
         test    %rcx,   %rcx
@@ -680,7 +680,7 @@ _vpaes_schedule_mangle:
 .type   ${PREFIX}_set_encrypt_key,\@function,3
 .align  16
 ${PREFIX}_set_encrypt_key:
-        endbr64
+        _CET_ENDBR
 ___
 $code.=<<___ if ($win64);
         lea     -0xb8(%rsp),%rsp
@@ -729,7 +729,7 @@ $code.=<<___;
 .type   ${PREFIX}_set_decrypt_key,\@function,3
 .align  16
 ${PREFIX}_set_decrypt_key:
-        endbr64
+        _CET_ENDBR
 ___
 $code.=<<___ if ($win64);
         lea     -0xb8(%rsp),%rsp
@@ -783,7 +783,7 @@ $code.=<<___;
 .type   ${PREFIX}_encrypt,\@function,3
 .align  16
 ${PREFIX}_encrypt:
-        endbr64
+        _CET_ENDBR
 ___
 $code.=<<___ if ($win64);
         lea     -0xb8(%rsp),%rsp
@@ -827,7 +827,7 @@ $code.=<<___;
 .type   ${PREFIX}_decrypt,\@function,3
 .align  16
 ${PREFIX}_decrypt:
-        endbr64
+        _CET_ENDBR
 ___
 $code.=<<___ if ($win64);
         lea     -0xb8(%rsp),%rsp
@@ -877,7 +877,7 @@ $code.=<<___;
 .type   ${PREFIX}_cbc_encrypt,\@function,6
 .align  16
 ${PREFIX}_cbc_encrypt:
-        endbr64
+        _CET_ENDBR
         xchg    $key,$len
 ___
 ($len,$key)=($key,$len);
@@ -961,7 +961,7 @@ $code.=<<___;
 .type   _vpaes_preheat,\@abi-omnipotent
 .align  16
 _vpaes_preheat:
-        endbr64
+        _CET_ENDBR
         lea     .Lk_s0F(%rip), %r10
         movdqa  -0x20(%r10), %xmm10     # .Lk_inv
         movdqa  -0x10(%r10), %xmm11     # .Lk_inv+16
@@ -1092,7 +1092,7 @@ $code.=<<___;
 .type   se_handler,\@abi-omnipotent
 .align  16
 se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_add.S b/src/lib/libcrypto/bn/arch/amd64/bignum_add.S
index 06298ca69e..5fe4aae7a1 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_add.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_add.S
@@ -49,7 +49,7 @@
 
 
 S2N_BN_SYMBOL(bignum_add):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_cmadd.S b/src/lib/libcrypto/bn/arch/amd64/bignum_cmadd.S
index 5ad712749f..25ba17bce2 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_cmadd.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_cmadd.S
@@ -54,7 +54,7 @@
 
 
 S2N_BN_SYMBOL(bignum_cmadd):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_cmul.S b/src/lib/libcrypto/bn/arch/amd64/bignum_cmul.S
index 9199c8f48b..12f785d63a 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_cmul.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_cmul.S
@@ -51,7 +51,7 @@
 
 
 S2N_BN_SYMBOL(bignum_cmul):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_mul.S b/src/lib/libcrypto/bn/arch/amd64/bignum_mul.S
index 2d7ed19091..a3552679a2 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_mul.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_mul.S
@@ -59,7 +59,7 @@
 
 
 S2N_BN_SYMBOL(bignum_mul):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_mul_4_8_alt.S b/src/lib/libcrypto/bn/arch/amd64/bignum_mul_4_8_alt.S
index f02b09b288..70ff69e372 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_mul_4_8_alt.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_mul_4_8_alt.S
@@ -72,7 +72,7 @@
         adc     h, rdx
 
 S2N_BN_SYMBOL(bignum_mul_4_8_alt):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_mul_8_16_alt.S b/src/lib/libcrypto/bn/arch/amd64/bignum_mul_8_16_alt.S
index 97be83e1f7..066403b074 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_mul_8_16_alt.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_mul_8_16_alt.S
@@ -72,7 +72,7 @@
         adc     h, rdx
 
 S2N_BN_SYMBOL(bignum_mul_8_16_alt):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_sqr.S b/src/lib/libcrypto/bn/arch/amd64/bignum_sqr.S
index c4a0cabf35..54e3f59442 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_sqr.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_sqr.S
@@ -62,7 +62,7 @@
 #define llshort ebp
 
 S2N_BN_SYMBOL(bignum_sqr):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_sqr_4_8_alt.S b/src/lib/libcrypto/bn/arch/amd64/bignum_sqr_4_8_alt.S
index b228414dce..7c534ae907 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_sqr_4_8_alt.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_sqr_4_8_alt.S
@@ -71,7 +71,7 @@
         adc     c, 0
 
 S2N_BN_SYMBOL(bignum_sqr_4_8_alt):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_sqr_8_16_alt.S b/src/lib/libcrypto/bn/arch/amd64/bignum_sqr_8_16_alt.S
index 04efeec7e2..ac0b6f96c2 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_sqr_8_16_alt.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_sqr_8_16_alt.S
@@ -103,7 +103,7 @@
         adc     c, 0
 
 S2N_BN_SYMBOL(bignum_sqr_8_16_alt):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/bignum_sub.S b/src/lib/libcrypto/bn/arch/amd64/bignum_sub.S
index 11a9bd7edd..3ff8a30510 100644
--- a/src/lib/libcrypto/bn/arch/amd64/bignum_sub.S
+++ b/src/lib/libcrypto/bn/arch/amd64/bignum_sub.S
@@ -49,7 +49,7 @@
 
 
 S2N_BN_SYMBOL(bignum_sub):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/arch/amd64/word_clz.S b/src/lib/libcrypto/bn/arch/amd64/word_clz.S
index 464a9d90fc..3926fcd4b0 100644
--- a/src/lib/libcrypto/bn/arch/amd64/word_clz.S
+++ b/src/lib/libcrypto/bn/arch/amd64/word_clz.S
@@ -30,7 +30,7 @@
         .text
 
 S2N_BN_SYMBOL(word_clz):
-        endbr64
+        _CET_ENDBR
 
 #if WINDOWS_ABI
         push    rdi
diff --git a/src/lib/libcrypto/bn/asm/modexp512-x86_64.pl b/src/lib/libcrypto/bn/asm/modexp512-x86_64.pl
index af78fff541..8645d5adcc 100644
--- a/src/lib/libcrypto/bn/asm/modexp512-x86_64.pl
+++ b/src/lib/libcrypto/bn/asm/modexp512-x86_64.pl
@@ -347,7 +347,7 @@ $code.=<<___;
 .type   MULADD_128x512,\@abi-omnipotent
 .align  16
 MULADD_128x512:
-        endbr64
+        _CET_ENDBR
 ___
         &MULSTEP_512([map("%r$_",(8..15))], "(+8*0)(%rcx)", "%rsi", "%rbp", "%rbx");
 $code.=<<___;
@@ -415,7 +415,7 @@ $code.=<<___;
 .type   mont_reduce,\@abi-omnipotent
 .align  16
 mont_reduce:
-        endbr64
+        _CET_ENDBR
 ___
 
 my $STACK_DEPTH         =  8;
@@ -678,7 +678,7 @@ $code.=<<___;
 .type   mont_mul_a3b,\@abi-omnipotent
 .align  16
 mont_mul_a3b:
-        endbr64
+        _CET_ENDBR
         #
         # multiply tmp = src1 * src2
         # For multiply: dst = rcx, src1 = rdi, src2 = rsi
@@ -1080,7 +1080,7 @@ $code.=<<___;
 .type   sqr_reduce,\@abi-omnipotent
 .align  16
 sqr_reduce:
-        endbr64
+        _CET_ENDBR
          mov    (+$pResult_offset+8)(%rsp), %rcx
 ___
         &SQR_512("%rsp+$tmp16_offset+8", "%rcx", [map("%r$_",(10..15,8..9))], "%rbx", "%rbp", "%rsi", "%rdi");
@@ -1110,7 +1110,7 @@ $code.=<<___;
 .globl  mod_exp_512
 .type   mod_exp_512,\@function,4
 mod_exp_512:
-        endbr64
+        _CET_ENDBR
          push   %rbp
          push   %rbx
          push   %r12
diff --git a/src/lib/libcrypto/bn/asm/x86_64-mont.pl b/src/lib/libcrypto/bn/asm/x86_64-mont.pl
index 6f5ab331e2..30cfab4fce 100755
--- a/src/lib/libcrypto/bn/asm/x86_64-mont.pl
+++ b/src/lib/libcrypto/bn/asm/x86_64-mont.pl
@@ -63,7 +63,7 @@ $code=<<___;
 .type   bn_mul_mont,\@function,6
 .align  16
 bn_mul_mont:
-        endbr64
+        _CET_ENDBR
         test    \$3,${num}d
         jnz     .Lmul_enter
         cmp     \$8,${num}d
@@ -279,7 +279,7 @@ $code.=<<___;
 .align  16
 bn_mul4x_mont:
 .Lmul4x_enter:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12
@@ -707,7 +707,7 @@ $code.=<<___;
 .align  16
 bn_sqr4x_mont:
 .Lsqr4x_enter:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12
diff --git a/src/lib/libcrypto/bn/asm/x86_64-mont5.pl b/src/lib/libcrypto/bn/asm/x86_64-mont5.pl
index 3b3325a6cc..38751ec5de 100755
--- a/src/lib/libcrypto/bn/asm/x86_64-mont5.pl
+++ b/src/lib/libcrypto/bn/asm/x86_64-mont5.pl
@@ -57,7 +57,7 @@ $code=<<___;
 .type   bn_mul_mont_gather5,\@function,6
 .align  64
 bn_mul_mont_gather5:
-        endbr64
+        _CET_ENDBR
         test    \$3,${num}d
         jnz     .Lmul_enter
         cmp     \$8,${num}d
@@ -388,7 +388,7 @@ $code.=<<___;
 .type   bn_mul4x_mont_gather5,\@function,6
 .align  16
 bn_mul4x_mont_gather5:
-        endbr64
+        _CET_ENDBR
 .Lmul4x_enter:
         mov     ${num}d,${num}d
         movd    `($win64?56:8)`(%rsp),%xmm5     # load 7th argument
@@ -927,7 +927,7 @@ $code.=<<___;
 .type   bn_scatter5,\@abi-omnipotent
 .align  16
 bn_scatter5:
-        endbr64
+        _CET_ENDBR
         cmp     \$0, $num
         jz      .Lscatter_epilogue
         lea     ($tbl,$idx,8),$tbl
@@ -946,7 +946,7 @@ bn_scatter5:
 .type   bn_gather5,\@abi-omnipotent
 .align  16
 bn_gather5:
-        endbr64
+        _CET_ENDBR
 .LSEH_begin_bn_gather5:                 # Win64 thing, but harmless in other cases
         # I can't trust assembler to use specific encoding:-(
         .byte   0x4c,0x8d,0x14,0x24                     # lea    (%rsp),%r10
@@ -1057,7 +1057,7 @@ $code.=<<___;
 .type   mul_handler,\@abi-omnipotent
 .align  16
 mul_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
diff --git a/src/lib/libcrypto/bn/s2n_bignum_internal.h b/src/lib/libcrypto/bn/s2n_bignum_internal.h
index f413688338..b82db7d019 100644
--- a/src/lib/libcrypto/bn/s2n_bignum_internal.h
+++ b/src/lib/libcrypto/bn/s2n_bignum_internal.h
@@ -18,6 +18,12 @@
 #   define S2N_BN_SYMBOL(name) name
 #endif
 
+#ifdef __CET__
+#   include <cet.h>
+#else
+#   define _CET_ENDBR
+#endif
+
 #define S2N_BN_SYM_VISIBILITY_DIRECTIVE(name) .globl S2N_BN_SYMBOL(name)
 #ifdef S2N_BN_HIDE_SYMBOLS
 #   ifdef __APPLE__
diff --git a/src/lib/libcrypto/camellia/asm/cmll-x86_64.pl b/src/lib/libcrypto/camellia/asm/cmll-x86_64.pl
index 3ceed3e899..187f0596d7 100644
--- a/src/lib/libcrypto/camellia/asm/cmll-x86_64.pl
+++ b/src/lib/libcrypto/camellia/asm/cmll-x86_64.pl
@@ -116,7 +116,7 @@ $code=<<___;
 .type   Camellia_EncryptBlock,\@abi-omnipotent
 .align  16
 Camellia_EncryptBlock:
-        endbr64
+        _CET_ENDBR
         movl    \$128,%eax
         subl    $arg0d,%eax
         movl    \$3,$arg0d
@@ -129,7 +129,7 @@ Camellia_EncryptBlock:
 .align  16
 .Lenc_rounds:
 Camellia_EncryptBlock_Rounds:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r13
@@ -178,7 +178,7 @@ Camellia_EncryptBlock_Rounds:
 .type   _x86_64_Camellia_encrypt,\@abi-omnipotent
 .align  16
 _x86_64_Camellia_encrypt:
-        endbr64
+        _CET_ENDBR
         xor     0($key),@S[1]
         xor     4($key),@S[0]           # ^=key[0-3]
         xor     8($key),@S[3]
@@ -229,7 +229,7 @@ $code.=<<___;
 .type   Camellia_DecryptBlock,\@abi-omnipotent
 .align  16
 Camellia_DecryptBlock:
-        endbr64
+        _CET_ENDBR
         movl    \$128,%eax
         subl    $arg0d,%eax
         movl    \$3,$arg0d
@@ -242,7 +242,7 @@ Camellia_DecryptBlock:
 .align  16
 .Ldec_rounds:
 Camellia_DecryptBlock_Rounds:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r13
@@ -291,7 +291,7 @@ Camellia_DecryptBlock_Rounds:
 .type   _x86_64_Camellia_decrypt,\@abi-omnipotent
 .align  16
 _x86_64_Camellia_decrypt:
-        endbr64
+        _CET_ENDBR
         xor     0($key),@S[1]
         xor     4($key),@S[0]           # ^=key[0-3]
         xor     8($key),@S[3]
@@ -406,7 +406,7 @@ $code.=<<___;
 .type   Camellia_Ekeygen,\@function,3
 .align  16
 Camellia_Ekeygen:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r13
@@ -637,7 +637,7 @@ $code.=<<___;
 .type   Camellia_cbc_encrypt,\@function,6
 .align  16
 Camellia_cbc_encrypt:
-        endbr64
+        _CET_ENDBR
         cmp     \$0,%rdx
         je      .Lcbc_abort
         push    %rbx
diff --git a/src/lib/libcrypto/md5/asm/md5-x86_64.pl b/src/lib/libcrypto/md5/asm/md5-x86_64.pl
index 06d69094f4..5001c34724 100755
--- a/src/lib/libcrypto/md5/asm/md5-x86_64.pl
+++ b/src/lib/libcrypto/md5/asm/md5-x86_64.pl
@@ -128,7 +128,7 @@ $code .= <<EOF;
 .globl md5_block_asm_data_order
 .type md5_block_asm_data_order,\@function,3
 md5_block_asm_data_order:
-        endbr64
+        _CET_ENDBR
         push    %rbp
         push    %rbx
         push    %r12
diff --git a/src/lib/libcrypto/modes/asm/ghash-x86_64.pl b/src/lib/libcrypto/modes/asm/ghash-x86_64.pl
index 4fded507c8..f3caac15d6 100644
--- a/src/lib/libcrypto/modes/asm/ghash-x86_64.pl
+++ b/src/lib/libcrypto/modes/asm/ghash-x86_64.pl
@@ -412,7 +412,7 @@ $code.=<<___;
 .type   gcm_init_clmul,\@abi-omnipotent
 .align  16
 gcm_init_clmul:
-        endbr64
+        _CET_ENDBR
         movdqu          ($Xip),$Hkey
         pshufd          \$0b01001110,$Hkey,$Hkey        # dword swap
 
@@ -450,7 +450,7 @@ $code.=<<___;
 .type   gcm_gmult_clmul,\@abi-omnipotent
 .align  16
 gcm_gmult_clmul:
-        endbr64
+        _CET_ENDBR
         movdqu          ($Xip),$Xi
         movdqa          .Lbswap_mask(%rip),$T3
         movdqu          ($Htbl),$Hkey
@@ -478,7 +478,7 @@ $code.=<<___;
 .type   gcm_ghash_clmul,\@abi-omnipotent
 .align  16
 gcm_ghash_clmul:
-        endbr64
+        _CET_ENDBR
 ___
 $code.=<<___ if ($win64);
 .LSEH_begin_gcm_ghash_clmul:
@@ -689,7 +689,7 @@ $code.=<<___;
 .type   se_handler,\@abi-omnipotent
 .align  16
 se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
diff --git a/src/lib/libcrypto/perlasm/x86_64-xlate.pl b/src/lib/libcrypto/perlasm/x86_64-xlate.pl
index 5dbed2a8c4..325e7cf583 100755
--- a/src/lib/libcrypto/perlasm/x86_64-xlate.pl
+++ b/src/lib/libcrypto/perlasm/x86_64-xlate.pl
@@ -781,6 +781,22 @@ ___
 OPTION  DOTNAME
 ___
 }
+
+if ($nasm) {
+        print <<___;
+\%define _CET_ENDBR
+___
+} else {
+        print <<___;
+#if defined(__CET__)
+#include <cet.h>
+#else
+#define _CET_ENDBR
+#endif
+
+___
+}
+
 print "#include \"x86_arch.h\"\n";
 
 while($line=<>) {
diff --git a/src/lib/libcrypto/rc4/asm/rc4-md5-x86_64.pl b/src/lib/libcrypto/rc4/asm/rc4-md5-x86_64.pl
index 3190e6a8e7..e5e8aa08a1 100644
--- a/src/lib/libcrypto/rc4/asm/rc4-md5-x86_64.pl
+++ b/src/lib/libcrypto/rc4/asm/rc4-md5-x86_64.pl
@@ -109,7 +109,7 @@ $code.=<<___;
 .globl  $func
 .type   $func,\@function,$nargs
 $func:
-        endbr64
+        _CET_ENDBR
         cmp     \$0,$len
         je      .Labort
         push    %rbx
@@ -454,7 +454,7 @@ $code.=<<___;
 .type   RC4_set_key,\@function,3
 .align  16
 RC4_set_key:
-        endbr64
+        _CET_ENDBR
         lea     8($dat),$dat
         lea     ($inp,$len),$inp
         neg     $len
diff --git a/src/lib/libcrypto/rc4/asm/rc4-x86_64.pl b/src/lib/libcrypto/rc4/asm/rc4-x86_64.pl
index 0472acce8a..a9cf9d1bdf 100755
--- a/src/lib/libcrypto/rc4/asm/rc4-x86_64.pl
+++ b/src/lib/libcrypto/rc4/asm/rc4-x86_64.pl
@@ -128,7 +128,7 @@ $code=<<___;
 .type   RC4,\@function,4
 .align  16
 RC4:
-        endbr64
+        _CET_ENDBR
         or      $len,$len
         jne     .Lentry
         ret
@@ -435,7 +435,7 @@ $code.=<<___;
 .type   RC4_set_key,\@function,3
 .align  16
 RC4_set_key:
-        endbr64
+        _CET_ENDBR
         lea     8($dat),$dat
         lea     ($inp,$len),$inp
         neg     $len
diff --git a/src/lib/libcrypto/sha/asm/sha1-x86_64.pl b/src/lib/libcrypto/sha/asm/sha1-x86_64.pl
index e15ff47f88..e080251df4 100755
--- a/src/lib/libcrypto/sha/asm/sha1-x86_64.pl
+++ b/src/lib/libcrypto/sha/asm/sha1-x86_64.pl
@@ -222,7 +222,7 @@ $code.=<<___;
 .type   sha1_block_data_order,\@function,3
 .align  16
 sha1_block_data_order:
-        endbr64
+        _CET_ENDBR
         mov     OPENSSL_ia32cap_P+0(%rip),%r9d
         mov     OPENSSL_ia32cap_P+4(%rip),%r8d
         test    \$IA32CAP_MASK1_SSSE3,%r8d              # check SSSE3 bit
@@ -310,7 +310,7 @@ $code.=<<___;
 .align  16
 sha1_block_data_order_ssse3:
 _ssse3_shortcut:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12
@@ -731,7 +731,7 @@ $code.=<<___;
 .align  16
 sha1_block_data_order_avx:
 _avx_shortcut:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12
@@ -1102,7 +1102,7 @@ $code.=<<___;
 .type   se_handler,\@abi-omnipotent
 .align  16
 se_handler:
-        endbr64
+        _CET_ENDBR
         push    %rsi
         push    %rdi
         push    %rbx
diff --git a/src/lib/libcrypto/sha/asm/sha512-x86_64.pl b/src/lib/libcrypto/sha/asm/sha512-x86_64.pl
index 120693feeb..f7a4dad2c9 100755
--- a/src/lib/libcrypto/sha/asm/sha512-x86_64.pl
+++ b/src/lib/libcrypto/sha/asm/sha512-x86_64.pl
@@ -175,7 +175,7 @@ $code=<<___;
 .type   $func,\@function,4
 .align  16
 $func:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12
diff --git a/src/lib/libcrypto/whrlpool/asm/wp-x86_64.pl b/src/lib/libcrypto/whrlpool/asm/wp-x86_64.pl
index 7958f6d289..2a3902430b 100644
--- a/src/lib/libcrypto/whrlpool/asm/wp-x86_64.pl
+++ b/src/lib/libcrypto/whrlpool/asm/wp-x86_64.pl
@@ -57,7 +57,7 @@ $code=<<___;
 .type   $func,\@function,3
 .align  16
 $func:
-        endbr64
+        _CET_ENDBR
         push    %rbx
         push    %rbp
         push    %r12
diff --git a/src/lib/libcrypto/x86_64cpuid.pl b/src/lib/libcrypto/x86_64cpuid.pl
index dc56732a28..5e85c40c97 100644
--- a/src/lib/libcrypto/x86_64cpuid.pl
+++ b/src/lib/libcrypto/x86_64cpuid.pl
@@ -18,7 +18,7 @@ print<<___;
 .extern         OPENSSL_cpuid_setup
 .hidden         OPENSSL_cpuid_setup
 .section        .init
-        endbr64
+        _CET_ENDBR
         call    OPENSSL_cpuid_setup
 
 .extern OPENSSL_ia32cap_P
@@ -30,7 +30,7 @@ print<<___;
 .type   OPENSSL_ia32_cpuid,\@abi-omnipotent
 .align  16
 OPENSSL_ia32_cpuid:
-        endbr64
+        _CET_ENDBR
         mov     %rbx,%r8                # save %rbx
 
         xor     %eax,%eax