ACK.--b.

On Tue, Feb 19, 2019 at 02:36:27PM -0500, Scott Mayhew wrote:

(cherry picked from commit e7afe6c1d486b516ed586dcc10b3e7e3e85a9c2b)

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@redhat.com Cc: stable@vger.kernel.org Signed-off-by: J. Bruce Fields bfields@redhat.com

Conflicts: net/sunrpc/auth_gss/gss_krb5_seqnum.c

---

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 c8b9082..2d2ed67 100644 --- a/net/sunrpc/auth_gss/gss_krb5_seqnum.c +++ b/net/sunrpc/auth_gss/gss_krb5_seqnum.c @@ -44,7 +44,7 @@ unsigned char *cksum, unsigned char *buf) { struct crypto_skcipher *cipher;

• unsigned char plain[8];

• unsigned char *plain; s32 code;

dprintk("RPC: %s:\n", __func__); @@ -53,6 +53,10 @@ 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);

@@ -69,6 +73,7 @@ code = krb5_encrypt(cipher, cksum, plain, buf, 8); out: crypto_free_skcipher(cipher);

• kfree(plain); return code;

} s32 @@ -78,12 +83,17 @@ 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);

@@ -94,7 +104,9 @@ 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 @@ -102,7 +114,7 @@ unsigned char *buf, int *direction, s32 *seqnum) { struct crypto_skcipher *cipher;

• unsigned char plain[8];

• unsigned char *plain; s32 code;

dprintk("RPC: %s:\n", __func__); @@ -115,20 +127,28 @@ 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_skcipher(cipher); return code; @@ -141,26 +161,33 @@ int *direction, u32 *seqnum) { s32 code;

• unsigned char plain[8]; struct crypto_skcipher *key = kctx->seq;

• unsigned char *plain;

dprintk("RPC: krb5_get_seq_num:\n"); 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;

}

1.8.3.1