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sunrpc: Don't use stack buffer with scatterlist

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Fedora got a bug report from NFS:

kernel BUG at include/linux/scatterlist.h:143!
...
RIP: 0010:sg_init_one+0x7d/0x90
..
  make_checksum+0x4e7/0x760 [rpcsec_gss_krb5]
  gss_get_mic_kerberos+0x26e/0x310 [rpcsec_gss_krb5]
  gss_marshal+0x126/0x1a0 [auth_rpcgss]
  ? __local_bh_enable_ip+0x80/0xe0
  ? call_transmit_status+0x1d0/0x1d0 [sunrpc]
  call_transmit+0x137/0x230 [sunrpc]
  __rpc_execute+0x9b/0x490 [sunrpc]
  rpc_run_task+0x119/0x150 [sunrpc]
  nfs4_run_exchange_id+0x1bd/0x250 [nfsv4]
  _nfs4_proc_exchange_id+0x2d/0x490 [nfsv4]
  nfs41_discover_server_trunking+0x1c/0xa0 [nfsv4]
  nfs4_discover_server_trunking+0x80/0x270 [nfsv4]
  nfs4_init_client+0x16e/0x240 [nfsv4]
  ? nfs_get_client+0x4c9/0x5d0 [nfs]
  ? _raw_spin_unlock+0x24/0x30
  ? nfs_get_client+0x4c9/0x5d0 [nfs]
  nfs4_set_client+0xb2/0x100 [nfsv4]
  nfs4_create_server+0xff/0x290 [nfsv4]
  nfs4_remote_mount+0x28/0x50 [nfsv4]
  mount_fs+0x3b/0x16a
  vfs_kern_mount.part.35+0x54/0x160
  nfs_do_root_mount+0x7f/0xc0 [nfsv4]
  nfs4_try_mount+0x43/0x70 [nfsv4]
  ? get_nfs_version+0x21/0x80 [nfs]
  nfs_fs_mount+0x789/0xbf0 [nfs]
  ? pcpu_alloc+0x6ca/0x7e0
  ? nfs_clone_super+0x70/0x70 [nfs]
  ? nfs_parse_mount_options+0xb40/0xb40 [nfs]
  mount_fs+0x3b/0x16a
  vfs_kern_mount.part.35+0x54/0x160
  do_mount+0x1fd/0xd50
  ksys_mount+0xba/0xd0
  __x64_sys_mount+0x21/0x30
  do_syscall_64+0x60/0x1f0
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

This is BUG_ON(!virt_addr_valid(buf)) triggered by using a stack
allocated buffer with a scatterlist. Convert the buffer for
rc4salt to be dynamically allocated instead.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1615258
Signed-off-by: Laura Abbott <labbott@redhat.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>
This commit is contained in:
Laura Abbott 2018-08-17 14:43:54 -07:00 committed by J. Bruce Fields
parent ac5bb5b3b0
commit 44090cc876
1 changed files with 9 additions and 3 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

12
net/sunrpc/auth_gss/gss_krb5_crypto.c
View file

@ -169,7 +169,7 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
struct scatterlist sg[1];
int err = -1;
u8 *checksumdata;
u8 rc4salt[4];
u8 *rc4salt;
struct crypto_ahash *md5;
struct crypto_ahash *hmac_md5;
struct ahash_request *req;
@ -183,14 +183,18 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
return GSS_S_FAILURE;
}
rc4salt = kmalloc_array(4, sizeof(*rc4salt), GFP_NOFS);
if (!rc4salt)
return GSS_S_FAILURE;
if (arcfour_hmac_md5_usage_to_salt(usage, rc4salt)) {
dprintk("%s: invalid usage value %u\n", __func__, usage);
return GSS_S_FAILURE;
goto out_free_rc4salt;
}
checksumdata = kmalloc(GSS_KRB5_MAX_CKSUM_LEN, GFP_NOFS);
if (!checksumdata)
return GSS_S_FAILURE;
goto out_free_rc4salt;
md5 = crypto_alloc_ahash("md5", 0, CRYPTO_ALG_ASYNC);
if (IS_ERR(md5))
@ -258,6 +262,8 @@ make_checksum_hmac_md5(struct krb5_ctx *kctx, char *header, int hdrlen,
crypto_free_ahash(md5);
out_free_cksum:
kfree(checksumdata);
out_free_rc4salt:
kfree(rc4salt);
return err ? GSS_S_FAILURE : 0;
}