From 6b635c74fd4135eaae68970bfc5aad9ae905fec7 Mon Sep 17 00:00:00 2001 From: Mark Johnston Date: Mon, 28 Aug 2023 21:26:53 -0400 Subject: [PATCH] aesni: Push FPU sections down further After commit 937b4473be21 aesni_cipher_crypt() and aesni_cipher_mac() execute in a FPU_KERN_NOCTX section, which means that they must run with preemption disabled. These functions handle discontiguous I/O buffers by allocating a contiguous buffer and copying as necessary, but this allocation cannot happen with preemption disabled. Fix the problem by pushing the FPU section down into aesni_cipher_crypt() and aesni_cipher_mac(). In particular, encrypt-then-auth transforms need not be handled with a single FPU section. Reported by: syzbot+78258dbb02eb92157357@syzkaller.appspotmail.com Discussed with: jhb Fixes: 937b4473be21 ("aesni: Switch to using FPU_KERN_NOCTX.") --- sys/crypto/aesni/aesni.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/sys/crypto/aesni/aesni.c b/sys/crypto/aesni/aesni.c index 6d83743dece9..5d5afd8aee41 100644 --- a/sys/crypto/aesni/aesni.c +++ b/sys/crypto/aesni/aesni.c @@ -594,8 +594,6 @@ aesni_cipher_process(struct aesni_session *ses, struct cryptop *crp) break; } - fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX); - /* Do work */ if (csp->csp_mode == CSP_MODE_ETA) { if (CRYPTO_OP_IS_ENCRYPT(crp->crp_op)) { @@ -612,7 +610,6 @@ aesni_cipher_process(struct aesni_session *ses, struct cryptop *crp) else error = aesni_cipher_crypt(ses, crp, csp); - fpu_kern_leave(curthread, NULL); return (error); } @@ -677,6 +674,8 @@ aesni_cipher_crypt(struct aesni_session *ses, struct cryptop *crp, outcopy = allocated; } + fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX); + error = 0; encflag = CRYPTO_OP_IS_ENCRYPT(crp->crp_op); if (crp->crp_cipher_key != NULL) @@ -749,6 +748,9 @@ aesni_cipher_crypt(struct aesni_session *ses, struct cryptop *crp, } break; } + + fpu_kern_leave(curthread, NULL); + if (outcopy && error == 0) crypto_copyback(crp, CRYPTO_HAS_OUTPUT_BUFFER(crp) ? crp->crp_payload_output_start : crp->crp_payload_start, @@ -784,6 +786,8 @@ aesni_cipher_mac(struct aesni_session *ses, struct cryptop *crp, key = csp->csp_auth_key; keylen = csp->csp_auth_klen; + fpu_kern_enter(curthread, NULL, FPU_KERN_NORMAL | FPU_KERN_NOCTX); + if (ses->hmac) { uint8_t hmac_key[SHA1_BLOCK_LEN] __aligned(16); @@ -849,6 +853,8 @@ aesni_cipher_mac(struct aesni_session *ses, struct cryptop *crp, ses->hash_finalize(res, &sctx); } + fpu_kern_leave(curthread, NULL); + if (crp->crp_op & CRYPTO_OP_VERIFY_DIGEST) { uint32_t res2[SHA2_256_HASH_LEN / sizeof(uint32_t)];