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use different values for DH for Cisco servers (#1026430)

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This commit is contained in:
Petr Lautrbach 2014-12-01 16:48:15 +01:00
parent 823364a11e
commit 08fe9e8e47
3 changed files with 81 additions and 16 deletions
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70
openssh-6.6.1p1-cisco-dh-keys.patch Normal file
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@ -0,0 +1,70 @@
diff --git a/compat.c b/compat.c
index 2709dc5..7412a54 100644
--- a/compat.c
+++ b/compat.c
@@ -167,6 +167,7 @@ compat_datafellows(const char *version)
SSH_BUG_SCANNER },
{ "Probe-*",
SSH_BUG_PROBE },
+ { "Cisco-*", SSH_BUG_MAX4096DH },
{ NULL, 0 }
};
diff --git a/compat.h b/compat.h
index a6c3f3d..d8def7d 100644
--- a/compat.h
+++ b/compat.h
@@ -60,6 +60,7 @@
#define SSH_NEW_OPENSSH 0x04000000
#define SSH_BUG_DYNAMIC_RPORT 0x08000000
#define SSH_BUG_CURVE25519PAD 0x10000000
+#define SSH_BUG_MAX4096DH 0x20000000
void enable_compat13(void);
void enable_compat20(void);
diff --git a/kexgexc.c b/kexgexc.c
index 355b7ba..0a91bdd 100644
--- a/kexgexc.c
+++ b/kexgexc.c
@@ -58,20 +58,37 @@ kexgex_client(Kex *kex)
int min, max, nbits;
DH *dh;
+ min = DH_GRP_MIN;
+ max = DH_GRP_MAX;
+
+ /* Servers with MAX4096DH need a preferred size (nbits) <= 4096.
+ * We need to also ensure that min < nbits < max */
+
+ if (datafellows & SSH_BUG_MAX4096DH) {
+ /* The largest min for these servers is 4096 */
+ min = MIN(min, 4096);
+ }
+
nbits = dh_estimate(kex->dh_need * 8);
+ nbits = MIN(nbits, max);
+ nbits = MAX(nbits, min);
+
+ if (datafellows & SSH_BUG_MAX4096DH) {
+ /* Cannot have a nbits > 4096 for these servers */
+ nbits = MIN(nbits, 4096);
+ /* nbits has to be powers of two */
+ if (nbits == 3072)
+ nbits = 4096;
+ }
if (datafellows & SSH_OLD_DHGEX) {
/* Old GEX request */
packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
packet_put_int(nbits);
- min = DH_GRP_MIN;
- max = DH_GRP_MAX;
debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD(%u) sent", nbits);
} else {
/* New GEX request */
- min = DH_GRP_MIN;
- max = DH_GRP_MAX;
packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
packet_put_int(min);
packet_put_int(nbits);

17
openssh-6.6p1-fips.patch
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@ -325,22 +325,15 @@ index 355b7ba..427e11f 100644
#include <sys/types.h>
#include <openssl/dh.h>
@@ -64,13 +66,13 @@ kexgex_client(Kex *kex)
/* Old GEX request */
packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST_OLD);
packet_put_int(nbits);
@@ -58,7 +60,7 @@ kexgex_client(Kex *kex)
int min, max, nbits;
DH *dh;
- min = DH_GRP_MIN;
+ min = FIPS_mode() ? DH_GRP_MIN_FIPS : DH_GRP_MIN;
max = DH_GRP_MAX;
debug("SSH2_MSG_KEX_DH_GEX_REQUEST_OLD(%u) sent", nbits);
} else {
/* New GEX request */
- min = DH_GRP_MIN;
+ min = FIPS_mode() ? DH_GRP_MIN_FIPS : DH_GRP_MIN;
max = DH_GRP_MAX;
packet_start(SSH2_MSG_KEX_DH_GEX_REQUEST);
packet_put_int(min);
/* Servers with MAX4096DH need a preferred size (nbits) <= 4096.
diff --git a/kexgexs.c b/kexgexs.c
index 770ad28..9d4fc6d 100644
--- a/kexgexs.c

4
openssh.spec
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@ -209,7 +209,8 @@ Patch914: openssh-6.6.1p1-servconf-parser.patch
Patch915: openssh-6.6.1p1-ignore-SIGXFSZ-in-postauth.patch
# privsep_preauth: use SELinux context from selinux-policy (#1008580)
Patch916: openssh-6.6.1p1-selinux-contexts.patch
# use different values for DH for Cisco servers (#1026430)
Patch917: openssh-6.6.1p1-cisco-dh-keys.patch
License: BSD
Group: Applications/Internet
@ -419,6 +420,7 @@ popd
%patch914 -p1 -b .servconf
%patch915 -p1 -b .SIGXFSZ
%patch916 -p1 -b .contexts
%patch917 -p1 -b .cisco-dh
%patch200 -p1 -b .audit
%patch700 -p1 -b .fips