| Message ID | 1419976254-30208-1-git-send-email-minipli@googlemail.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Herbert Xu |
| Headers | show |
On 30/12/2014 14:50, Mathias Krause wrote: > The "by8" counter mode optimization is broken for 128 bit keys with > input data longer than 128 bytes. It uses the wrong key material for > en- and decryption. > > The key registers xkey0, xkey4, xkey8 and xkey12 need to be preserved > in case we're handling more than 128 bytes of input data -- they won't > get reloaded after the initial load. They must therefore be (a) loaded > on the first iteration and (b) be preserved for the latter ones. The > implementation for 128 bit keys does not comply with (a) nor (b). > > Fix this by bringing the implementation back to its original source > and correctly load the key registers and preserve their values by > *not* re-using the registers for other purposes. > > Kudos to James for reporting the issue and providing a test case > showing the discrepancies. > > Reported-by: James Yonan <james@openvpn.net> > Cc: Chandramouli Narayanan <mouli@linux.intel.com> > Cc: <stable@vger.kernel.org> # v3.18 > Signed-off-by: Mathias Krause <minipli@googlemail.com> This looks great, fixes the issue on 3.18.1 for all of our use cases. Thanks to Mathias for putting this together. James -- To unsubscribe from this list: send the line "unsubscribe linux-crypto" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
On Thu, Jan 01, 2015 at 10:08:18AM -0700, James Yonan wrote: > On 30/12/2014 14:50, Mathias Krause wrote: > >The "by8" counter mode optimization is broken for 128 bit keys with > >input data longer than 128 bytes. It uses the wrong key material for > >en- and decryption. > > > >The key registers xkey0, xkey4, xkey8 and xkey12 need to be preserved > >in case we're handling more than 128 bytes of input data -- they won't > >get reloaded after the initial load. They must therefore be (a) loaded > >on the first iteration and (b) be preserved for the latter ones. The > >implementation for 128 bit keys does not comply with (a) nor (b). > > > >Fix this by bringing the implementation back to its original source > >and correctly load the key registers and preserve their values by > >*not* re-using the registers for other purposes. > > > >Kudos to James for reporting the issue and providing a test case > >showing the discrepancies. > > > >Reported-by: James Yonan <james@openvpn.net> > >Cc: Chandramouli Narayanan <mouli@linux.intel.com> > >Cc: <stable@vger.kernel.org> # v3.18 > >Signed-off-by: Mathias Krause <minipli@googlemail.com> > > This looks great, fixes the issue on 3.18.1 for all of our use cases. > > Thanks to Mathias for putting this together. Patch applied to crypto. Thanks a lot!
diff --git a/arch/x86/crypto/aes_ctrby8_avx-x86_64.S b/arch/x86/crypto/aes_ctrby8_avx-x86_64.S index 2df2a0298f5a..a916c4a61165 100644 --- a/arch/x86/crypto/aes_ctrby8_avx-x86_64.S +++ b/arch/x86/crypto/aes_ctrby8_avx-x86_64.S @@ -208,7 +208,7 @@ ddq_add_8: .if (klen == KEY_128) .if (load_keys) - vmovdqa 3*16(p_keys), xkeyA + vmovdqa 3*16(p_keys), xkey4 .endif .else vmovdqa 3*16(p_keys), xkeyA @@ -224,7 +224,7 @@ ddq_add_8: add $(16*by), p_in .if (klen == KEY_128) - vmovdqa 4*16(p_keys), xkey4 + vmovdqa 4*16(p_keys), xkeyB .else .if (load_keys) vmovdqa 4*16(p_keys), xkey4 @@ -234,7 +234,12 @@ ddq_add_8: .set i, 0 .rept by club XDATA, i - vaesenc xkeyA, var_xdata, var_xdata /* key 3 */ + /* key 3 */ + .if (klen == KEY_128) + vaesenc xkey4, var_xdata, var_xdata + .else + vaesenc xkeyA, var_xdata, var_xdata + .endif .set i, (i +1) .endr @@ -243,13 +248,18 @@ ddq_add_8: .set i, 0 .rept by club XDATA, i - vaesenc xkey4, var_xdata, var_xdata /* key 4 */ + /* key 4 */ + .if (klen == KEY_128) + vaesenc xkeyB, var_xdata, var_xdata + .else + vaesenc xkey4, var_xdata, var_xdata + .endif .set i, (i +1) .endr .if (klen == KEY_128) .if (load_keys) - vmovdqa 6*16(p_keys), xkeyB + vmovdqa 6*16(p_keys), xkey8 .endif .else vmovdqa 6*16(p_keys), xkeyB @@ -267,12 +277,17 @@ ddq_add_8: .set i, 0 .rept by club XDATA, i - vaesenc xkeyB, var_xdata, var_xdata /* key 6 */ + /* key 6 */ + .if (klen == KEY_128) + vaesenc xkey8, var_xdata, var_xdata + .else + vaesenc xkeyB, var_xdata, var_xdata + .endif .set i, (i +1) .endr .if (klen == KEY_128) - vmovdqa 8*16(p_keys), xkey8 + vmovdqa 8*16(p_keys), xkeyB .else .if (load_keys) vmovdqa 8*16(p_keys), xkey8 @@ -288,7 +303,7 @@ ddq_add_8: .if (klen == KEY_128) .if (load_keys) - vmovdqa 9*16(p_keys), xkeyA + vmovdqa 9*16(p_keys), xkey12 .endif .else vmovdqa 9*16(p_keys), xkeyA @@ -297,7 +312,12 @@ ddq_add_8: .set i, 0 .rept by club XDATA, i - vaesenc xkey8, var_xdata, var_xdata /* key 8 */ + /* key 8 */ + .if (klen == KEY_128) + vaesenc xkeyB, var_xdata, var_xdata + .else + vaesenc xkey8, var_xdata, var_xdata + .endif .set i, (i +1) .endr @@ -306,7 +326,12 @@ ddq_add_8: .set i, 0 .rept by club XDATA, i - vaesenc xkeyA, var_xdata, var_xdata /* key 9 */ + /* key 9 */ + .if (klen == KEY_128) + vaesenc xkey12, var_xdata, var_xdata + .else + vaesenc xkeyA, var_xdata, var_xdata + .endif .set i, (i +1) .endr @@ -412,7 +437,6 @@ ddq_add_8: /* main body of aes ctr load */ .macro do_aes_ctrmain key_len - cmp $16, num_bytes jb .Ldo_return2\key_len
The "by8" counter mode optimization is broken for 128 bit keys with input data longer than 128 bytes. It uses the wrong key material for en- and decryption. The key registers xkey0, xkey4, xkey8 and xkey12 need to be preserved in case we're handling more than 128 bytes of input data -- they won't get reloaded after the initial load. They must therefore be (a) loaded on the first iteration and (b) be preserved for the latter ones. The implementation for 128 bit keys does not comply with (a) nor (b). Fix this by bringing the implementation back to its original source and correctly load the key registers and preserve their values by *not* re-using the registers for other purposes. Kudos to James for reporting the issue and providing a test case showing the discrepancies. Reported-by: James Yonan <james@openvpn.net> Cc: Chandramouli Narayanan <mouli@linux.intel.com> Cc: <stable@vger.kernel.org> # v3.18 Signed-off-by: Mathias Krause <minipli@googlemail.com> --- James, this should fix the issue for you, too -- it did for me, using your test case. Feel free to add your 'Tested-by' if it does. This patch should go on top of crypto-2.6.git#master as it's a fix that needs to go to stable as well. arch/x86/crypto/aes_ctrby8_avx-x86_64.S | 46 +++++++++++++++++++++++-------- 1 file changed, 35 insertions(+), 11 deletions(-)