From: Eric Biggers ebiggers@google.com

Clear the CRYPTO_TFM_REQ_MAY_SLEEP flag when the chacha20poly1305 operation is being continued from an async completion callback, since sleeping may not be allowed in that context.

This is basically the same bug that was recently fixed in the xts and lrw templates. But, it's always been broken in chacha20poly1305 too. This was found using syzkaller in combination with the updated crypto self-tests which actually test the MAY_SLEEP flag now.

Reproducer:

python -c 'import socket; socket.socket(socket.AF_ALG, 5, 0).bind( ("aead", "rfc7539(cryptd(chacha20-generic),poly1305-generic)"))'

Kernel output:

BUG: sleeping function called from invalid context at include/crypto/algapi.h:426 in_atomic(): 1, irqs_disabled(): 0, pid: 1001, name: kworker/2:2 [...] CPU: 2 PID: 1001 Comm: kworker/2:2 Not tainted 5.2.0-rc2 #5 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-20181126_142135-anatol 04/01/2014 Workqueue: crypto cryptd_queue_worker Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x4d/0x6a lib/dump_stack.c:113 ___might_sleep kernel/sched/core.c:6138 [inline] ___might_sleep.cold.19+0x8e/0x9f kernel/sched/core.c:6095 crypto_yield include/crypto/algapi.h:426 [inline] crypto_hash_walk_done+0xd6/0x100 crypto/ahash.c:113 shash_ahash_update+0x41/0x60 crypto/shash.c:251 shash_async_update+0xd/0x10 crypto/shash.c:260 crypto_ahash_update include/crypto/hash.h:539 [inline] poly_setkey+0xf6/0x130 crypto/chacha20poly1305.c:337 poly_init+0x51/0x60 crypto/chacha20poly1305.c:364 async_done_continue crypto/chacha20poly1305.c:78 [inline] poly_genkey_done+0x15/0x30 crypto/chacha20poly1305.c:369 cryptd_skcipher_complete+0x29/0x70 crypto/cryptd.c:279 cryptd_skcipher_decrypt+0xcd/0x110 crypto/cryptd.c:339 cryptd_queue_worker+0x70/0xa0 crypto/cryptd.c:184 process_one_work+0x1ed/0x420 kernel/workqueue.c:2269 worker_thread+0x3e/0x3a0 kernel/workqueue.c:2415 kthread+0x11f/0x140 kernel/kthread.c:255 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:352

Fixes: 71ebc4d1b27d ("crypto: chacha20poly1305 - Add a ChaCha20-Poly1305 AEAD construction, RFC7539") Cc: stable@vger.kernel.org # v4.2+ Cc: Martin Willi martin@strongswan.org Signed-off-by: Eric Biggers ebiggers@google.com --- crypto/chacha20poly1305.c | 30 +++++++++++++++++++----------- 1 file changed, 19 insertions(+), 11 deletions(-)

diff --git a/crypto/chacha20poly1305.c b/crypto/chacha20poly1305.c index e38a2d61819a7..acbbf010222e3 100644 --- a/crypto/chacha20poly1305.c +++ b/crypto/chacha20poly1305.c @@ -65,6 +65,8 @@ struct chachapoly_req_ctx { unsigned int cryptlen; /* Actual AD, excluding IV */ unsigned int assoclen; + /* request flags, with MAY_SLEEP cleared if needed */ + u32 flags; union { struct poly_req poly; struct chacha_req chacha; @@ -74,8 +76,12 @@ struct chachapoly_req_ctx { static inline void async_done_continue(struct aead_request *req, int err, int (*cont)(struct aead_request *)) { - if (!err) + if (!err) { + struct chachapoly_req_ctx *rctx = aead_request_ctx(req); + + rctx->flags &= ~CRYPTO_TFM_REQ_MAY_SLEEP; err = cont(req); + }

if (err != -EINPROGRESS && err != -EBUSY) aead_request_complete(req, err); @@ -142,7 +148,7 @@ static int chacha_decrypt(struct aead_request *req) dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen); }

- skcipher_request_set_callback(&creq->req, aead_request_flags(req), + skcipher_request_set_callback(&creq->req, rctx->flags, chacha_decrypt_done, req); skcipher_request_set_tfm(&creq->req, ctx->chacha); skcipher_request_set_crypt(&creq->req, src, dst, @@ -186,7 +192,7 @@ static int poly_tail(struct aead_request *req) memcpy(&preq->tail.cryptlen, &len, sizeof(len)); sg_set_buf(preq->src, &preq->tail, sizeof(preq->tail));

- ahash_request_set_callback(&preq->req, aead_request_flags(req), + ahash_request_set_callback(&preq->req, rctx->flags, poly_tail_done, req); ahash_request_set_tfm(&preq->req, ctx->poly); ahash_request_set_crypt(&preq->req, preq->src, @@ -217,7 +223,7 @@ static int poly_cipherpad(struct aead_request *req) sg_init_table(preq->src, 1); sg_set_buf(preq->src, &preq->pad, padlen);

- ahash_request_set_callback(&preq->req, aead_request_flags(req), + ahash_request_set_callback(&preq->req, rctx->flags, poly_cipherpad_done, req); ahash_request_set_tfm(&preq->req, ctx->poly); ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen); @@ -248,7 +254,7 @@ static int poly_cipher(struct aead_request *req) sg_init_table(rctx->src, 2); crypt = scatterwalk_ffwd(rctx->src, crypt, req->assoclen);

- ahash_request_set_callback(&preq->req, aead_request_flags(req), + ahash_request_set_callback(&preq->req, rctx->flags, poly_cipher_done, req); ahash_request_set_tfm(&preq->req, ctx->poly); ahash_request_set_crypt(&preq->req, crypt, NULL, rctx->cryptlen); @@ -278,7 +284,7 @@ static int poly_adpad(struct aead_request *req) sg_init_table(preq->src, 1); sg_set_buf(preq->src, preq->pad, padlen);

- ahash_request_set_callback(&preq->req, aead_request_flags(req), + ahash_request_set_callback(&preq->req, rctx->flags, poly_adpad_done, req); ahash_request_set_tfm(&preq->req, ctx->poly); ahash_request_set_crypt(&preq->req, preq->src, NULL, padlen); @@ -302,7 +308,7 @@ static int poly_ad(struct aead_request *req) struct poly_req *preq = &rctx->u.poly; int err;

- ahash_request_set_callback(&preq->req, aead_request_flags(req), + ahash_request_set_callback(&preq->req, rctx->flags, poly_ad_done, req); ahash_request_set_tfm(&preq->req, ctx->poly); ahash_request_set_crypt(&preq->req, req->src, NULL, rctx->assoclen); @@ -329,7 +335,7 @@ static int poly_setkey(struct aead_request *req) sg_init_table(preq->src, 1); sg_set_buf(preq->src, rctx->key, sizeof(rctx->key));

- ahash_request_set_callback(&preq->req, aead_request_flags(req), + ahash_request_set_callback(&preq->req, rctx->flags, poly_setkey_done, req); ahash_request_set_tfm(&preq->req, ctx->poly); ahash_request_set_crypt(&preq->req, preq->src, NULL, sizeof(rctx->key)); @@ -353,7 +359,7 @@ static int poly_init(struct aead_request *req) struct poly_req *preq = &rctx->u.poly; int err;

- ahash_request_set_callback(&preq->req, aead_request_flags(req), + ahash_request_set_callback(&preq->req, rctx->flags, poly_init_done, req); ahash_request_set_tfm(&preq->req, ctx->poly);

@@ -391,7 +397,7 @@ static int poly_genkey(struct aead_request *req)

chacha_iv(creq->iv, req, 0);

- skcipher_request_set_callback(&creq->req, aead_request_flags(req), + skcipher_request_set_callback(&creq->req, rctx->flags, poly_genkey_done, req); skcipher_request_set_tfm(&creq->req, ctx->chacha); skcipher_request_set_crypt(&creq->req, creq->src, creq->src, @@ -431,7 +437,7 @@ static int chacha_encrypt(struct aead_request *req) dst = scatterwalk_ffwd(rctx->dst, req->dst, req->assoclen); }

- skcipher_request_set_callback(&creq->req, aead_request_flags(req), + skcipher_request_set_callback(&creq->req, rctx->flags, chacha_encrypt_done, req); skcipher_request_set_tfm(&creq->req, ctx->chacha); skcipher_request_set_crypt(&creq->req, src, dst, @@ -449,6 +455,7 @@ static int chachapoly_encrypt(struct aead_request *req) struct chachapoly_req_ctx *rctx = aead_request_ctx(req);

rctx->cryptlen = req->cryptlen; + rctx->flags = aead_request_flags(req);

/* encrypt call chain: * - chacha_encrypt/done() @@ -470,6 +477,7 @@ static int chachapoly_decrypt(struct aead_request *req) struct chachapoly_req_ctx *rctx = aead_request_ctx(req);

rctx->cryptlen = req->cryptlen - POLY1305_DIGEST_SIZE; + rctx->flags = aead_request_flags(req);

/* decrypt call chain: * - poly_genkey/done()