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Subject[PATCH 4.4 23/79] crypto: caam - fix concurrency issue in givencrypt descriptor
Date
From: Horia Geantă <horia.geanta@nxp.com>

commit 48f89d2a2920166c35b1c0b69917dbb0390ebec7 upstream.

IV transfer from ofifo to class2 (set up at [29][30]) is not guaranteed
to be scheduled before the data transfer from ofifo to external memory
(set up at [38]:

[29] 10FA0004 ld: ind-nfifo (len=4) imm
[30] 81F00010 <nfifo_entry: ofifo->class2 type=msg len=16>
[31] 14820004 ld: ccb2-datasz len=4 offs=0 imm
[32] 00000010 data:0x00000010
[33] 8210010D operation: cls1-op aes cbc init-final enc
[34] A8080B04 math: (seqin + math0)->vseqout len=4
[35] 28000010 seqfifold: skip len=16
[36] A8080A04 math: (seqin + math0)->vseqin len=4
[37] 2F1E0000 seqfifold: both msg1->2-last2-last1 len=vseqinsz
[38] 69300000 seqfifostr: msg len=vseqoutsz
[39] 5C20000C seqstr: ccb2 ctx len=12 offs=0

If ofifo -> external memory transfer happens first, DECO will hang
(issuing a Watchdog Timeout error, if WDOG is enabled) waiting for
data availability in ofifo for the ofifo -> c2 ififo transfer.

Make sure IV transfer happens first by waiting for all CAAM internal
transfers to end before starting payload transfer.

New descriptor with jump command inserted at [37]:

[..]
[36] A8080A04 math: (seqin + math0)->vseqin len=4
[37] A1000401 jump: jsl1 all-match[!nfifopend] offset=[01] local->[38]
[38] 2F1E0000 seqfifold: both msg1->2-last2-last1 len=vseqinsz
[39] 69300000 seqfifostr: msg len=vseqoutsz
[40] 5C20000C seqstr: ccb2 ctx len=12 offs=0

[Note: the issue is present in the descriptor from the very beginning
(cf. Fixes tag). However I've marked it v4.19+ since it's the oldest
maintained kernel that the patch applies clean against.]

Cc: <stable@vger.kernel.org> # v4.19+
Fixes: 1acebad3d8db8 ("crypto: caam - faster aead implementation")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[Horia: backport to v4.4, v4.9]
Signed-off-by: Horia Geantă <horia.geanta@nxp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/crypto/caam/caamalg.c | 11 ++++++++++-
1 file changed, 10 insertions(+), 1 deletion(-)

--- a/drivers/crypto/caam/caamalg.c
+++ b/drivers/crypto/caam/caamalg.c
@@ -75,7 +75,7 @@
#define DESC_AEAD_BASE (4 * CAAM_CMD_SZ)
#define DESC_AEAD_ENC_LEN (DESC_AEAD_BASE + 11 * CAAM_CMD_SZ)
#define DESC_AEAD_DEC_LEN (DESC_AEAD_BASE + 15 * CAAM_CMD_SZ)
-#define DESC_AEAD_GIVENC_LEN (DESC_AEAD_ENC_LEN + 9 * CAAM_CMD_SZ)
+#define DESC_AEAD_GIVENC_LEN (DESC_AEAD_ENC_LEN + 10 * CAAM_CMD_SZ)

/* Note: Nonce is counted in enckeylen */
#define DESC_AEAD_CTR_RFC3686_LEN (4 * CAAM_CMD_SZ)
@@ -437,6 +437,7 @@ static int aead_set_sh_desc(struct crypt
u32 geniv, moveiv;
u32 ctx1_iv_off = 0;
u32 *desc;
+ u32 *wait_cmd;
const bool ctr_mode = ((ctx->class1_alg_type & OP_ALG_AAI_MASK) ==
OP_ALG_AAI_CTR_MOD128);
const bool is_rfc3686 = alg->caam.rfc3686;
@@ -702,6 +703,14 @@ copy_iv:

/* Will read cryptlen */
append_math_add(desc, VARSEQINLEN, SEQINLEN, REG0, CAAM_CMD_SZ);
+
+ /*
+ * Wait for IV transfer (ofifo -> class2) to finish before starting
+ * ciphertext transfer (ofifo -> external memory).
+ */
+ wait_cmd = append_jump(desc, JUMP_JSL | JUMP_TEST_ALL | JUMP_COND_NIFP);
+ set_jump_tgt_here(desc, wait_cmd);
+
append_seq_fifo_load(desc, 0, FIFOLD_CLASS_BOTH | KEY_VLF |
FIFOLD_TYPE_MSG1OUT2 | FIFOLD_TYPE_LASTBOTH);
append_seq_fifo_store(desc, 0, FIFOST_TYPE_MESSAGE_DATA | KEY_VLF);

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