While trying to reproduce a reported kernel panic on arm64, I discovered
that AUTH_GSS basically doesn't work at all with older enctypes on arm64
systems with CONFIG_VMAP_STACK enabled. It turns out there still a few
places using stack memory with scatterlists, causing krb5_encrypt() and
krb5_decrypt() to produce incorrect results (or a BUG if CONFIG_DEBUG_SG
is enabled).
Tested with cthon on v4.0/v4.1/v4.2 with krb5/krb5i/krb5p using
des3-cbc-sha1 and arcfour-hmac-md5.
Signed-off-by: Scott Mayhew <smayhew@xxxxxxxxxx>
---
net/sunrpc/auth_gss/gss_krb5_seqnum.c | 49 +++++++++++++++++++++------
1 file changed, 38 insertions(+), 11 deletions(-)
diff --git a/net/sunrpc/auth_gss/gss_krb5_seqnum.c b/net/sunrpc/auth_gss/gss_krb5_seqnum.c
index fb6656295204..507105127095 100644
--- a/net/sunrpc/auth_gss/gss_krb5_seqnum.c
+++ b/net/sunrpc/auth_gss/gss_krb5_seqnum.c
@@ -44,7 +44,7 @@ krb5_make_rc4_seq_num(struct krb5_ctx *kctx, int direction, s32 seqnum,
unsigned char *cksum, unsigned char *buf)
{
struct crypto_sync_skcipher *cipher;
- unsigned char plain[8];
+ unsigned char *plain;
s32 code;
dprintk("RPC: %s:\n", __func__);
@@ -52,6 +52,10 @@ krb5_make_rc4_seq_num(struct krb5_ctx *kctx, int direction, s32 seqnum,
if (IS_ERR(cipher))
return PTR_ERR(cipher);
+ plain = kmalloc(8, GFP_NOFS);
+ if (!plain)
+ return -ENOMEM;
+
plain[0] = (unsigned char) ((seqnum >> 24) & 0xff);
plain[1] = (unsigned char) ((seqnum >> 16) & 0xff);
plain[2] = (unsigned char) ((seqnum >> 8) & 0xff);
@@ -67,6 +71,7 @@ krb5_make_rc4_seq_num(struct krb5_ctx *kctx, int direction, s32 seqnum,
code = krb5_encrypt(cipher, cksum, plain, buf, 8);
out:
+ kfree(plain);
crypto_free_sync_skcipher(cipher);
return code;
}
@@ -77,12 +82,17 @@ krb5_make_seq_num(struct krb5_ctx *kctx,
u32 seqnum,
unsigned char *cksum, unsigned char *buf)
{
- unsigned char plain[8];
+ unsigned char *plain;
+ s32 code;
if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
return krb5_make_rc4_seq_num(kctx, direction, seqnum,
cksum, buf);
+ plain = kmalloc(8, GFP_NOFS);
+ if (!plain)
+ return -ENOMEM;
+
plain[0] = (unsigned char) (seqnum & 0xff);
plain[1] = (unsigned char) ((seqnum >> 8) & 0xff);
plain[2] = (unsigned char) ((seqnum >> 16) & 0xff);
@@ -93,7 +103,9 @@ krb5_make_seq_num(struct krb5_ctx *kctx,
plain[6] = direction;
plain[7] = direction;
- return krb5_encrypt(key, cksum, plain, buf, 8);
+ code = krb5_encrypt(key, cksum, plain, buf, 8);
+ kfree(plain);
+ return code;
}
static s32
@@ -101,7 +113,7 @@ krb5_get_rc4_seq_num(struct krb5_ctx *kctx, unsigned char *cksum,
unsigned char *buf, int *direction, s32 *seqnum)
{
struct crypto_sync_skcipher *cipher;
- unsigned char plain[8];
+ unsigned char *plain;
s32 code;
dprintk("RPC: %s:\n", __func__);
@@ -113,20 +125,28 @@ krb5_get_rc4_seq_num(struct krb5_ctx *kctx, unsigned char *cksum,
if (code)
goto out;
+ plain = kmalloc(8, GFP_NOFS);
+ if (!plain) {
+ code = -ENOMEM;
+ goto out;
+ }
+
code = krb5_decrypt(cipher, cksum, buf, plain, 8);
if (code)
- goto out;
+ goto out_plain;
if ((plain[4] != plain[5]) || (plain[4] != plain[6])
|| (plain[4] != plain[7])) {
code = (s32)KG_BAD_SEQ;
- goto out;
+ goto out_plain;
}
*direction = plain[4];
*seqnum = ((plain[0] << 24) | (plain[1] << 16) |
(plain[2] << 8) | (plain[3]));
+out_plain:
+ kfree(plain);
out:
crypto_free_sync_skcipher(cipher);
return code;
@@ -139,7 +159,7 @@ krb5_get_seq_num(struct krb5_ctx *kctx,
int *direction, u32 *seqnum)
{
s32 code;
- unsigned char plain[8];
+ unsigned char *plain;
struct crypto_sync_skcipher *key = kctx->seq;
dprintk("RPC: krb5_get_seq_num:\n");
@@ -147,18 +167,25 @@ krb5_get_seq_num(struct krb5_ctx *kctx,
if (kctx->enctype == ENCTYPE_ARCFOUR_HMAC)
return krb5_get_rc4_seq_num(kctx, cksum, buf,
direction, seqnum);
+ plain = kmalloc(8, GFP_NOFS);
+ if (!plain)
+ return -ENOMEM;
if ((code = krb5_decrypt(key, cksum, buf, plain, 8)))
- return code;
+ goto out;
if ((plain[4] != plain[5]) || (plain[4] != plain[6]) ||
- (plain[4] != plain[7]))
- return (s32)KG_BAD_SEQ;
+ (plain[4] != plain[7])) {
+ code = (s32)KG_BAD_SEQ;
+ goto out;
+ }
*direction = plain[4];
*seqnum = ((plain[0]) |
(plain[1] << 8) | (plain[2] << 16) | (plain[3] << 24));
- return 0;
+out:
+ kfree(plain);
+ return code;
}
--
2.17.2
