* [PATCH v3 1/2] SUNRPC: Move simple_get_bytes and simple_get_netobj into private header
2021-01-21 21:17 [PATCH v3 0/2] Fix crash in trace_rpcgss_context due to 0-length acceptor Dave Wysochanski
@ 2021-01-21 21:17 ` Dave Wysochanski
2021-01-21 21:17 ` [PATCH v3 2/2] SUNRPC: Handle 0 length opaque XDR object data properly Dave Wysochanski
1 sibling, 0 replies; 3+ messages in thread
From: Dave Wysochanski @ 2021-01-21 21:17 UTC (permalink / raw)
To: Trond Myklebust, Anna Schumaker; +Cc: linux-nfs
Remove duplicated helper functions to parse opaque XDR objects
and place inside new file net/sunrpc/auth_gss/auth_gss_internal.h.
In the new file carry the license and copyright from the source file
net/sunrpc/auth_gss/auth_gss.c. Finally, update the comment inside
include/linux/sunrpc/xdr.h since lockd is not the only user of
struct xdr_netobj.
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
---
include/linux/sunrpc/xdr.h | 3 +--
net/sunrpc/auth_gss/auth_gss.c | 30 +----------------------
net/sunrpc/auth_gss/auth_gss_internal.h | 42 +++++++++++++++++++++++++++++++++
net/sunrpc/auth_gss/gss_krb5_mech.c | 31 ++----------------------
4 files changed, 46 insertions(+), 60 deletions(-)
create mode 100644 net/sunrpc/auth_gss/auth_gss_internal.h
diff --git a/include/linux/sunrpc/xdr.h b/include/linux/sunrpc/xdr.h
index 19b6dea27367..b26213ae8c1a 100644
--- a/include/linux/sunrpc/xdr.h
+++ b/include/linux/sunrpc/xdr.h
@@ -25,8 +25,7 @@
#define XDR_QUADLEN(l) (((l) + 3) >> 2)
/*
- * Generic opaque `network object.' At the kernel level, this type
- * is used only by lockd.
+ * Generic opaque `network object.'
*/
#define XDR_MAX_NETOBJ 1024
struct xdr_netobj {
diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index 4ecc2a959567..5f42aa5fc612 100644
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -29,6 +29,7 @@
#include <linux/uaccess.h>
#include <linux/hashtable.h>
+#include "auth_gss_internal.h"
#include "../netns.h"
#include <trace/events/rpcgss.h>
@@ -125,35 +126,6 @@ struct gss_auth {
clear_bit(RPCAUTH_CRED_NEW, &cred->cr_flags);
}
-static const void *
-simple_get_bytes(const void *p, const void *end, void *res, size_t len)
-{
- const void *q = (const void *)((const char *)p + len);
- if (unlikely(q > end || q < p))
- return ERR_PTR(-EFAULT);
- memcpy(res, p, len);
- return q;
-}
-
-static inline const void *
-simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
-{
- const void *q;
- unsigned int len;
-
- p = simple_get_bytes(p, end, &len, sizeof(len));
- if (IS_ERR(p))
- return p;
- q = (const void *)((const char *)p + len);
- if (unlikely(q > end || q < p))
- return ERR_PTR(-EFAULT);
- dest->data = kmemdup(p, len, GFP_NOFS);
- if (unlikely(dest->data == NULL))
- return ERR_PTR(-ENOMEM);
- dest->len = len;
- return q;
-}
-
static struct gss_cl_ctx *
gss_cred_get_ctx(struct rpc_cred *cred)
{
diff --git a/net/sunrpc/auth_gss/auth_gss_internal.h b/net/sunrpc/auth_gss/auth_gss_internal.h
new file mode 100644
index 000000000000..c5603242b54b
--- /dev/null
+++ b/net/sunrpc/auth_gss/auth_gss_internal.h
@@ -0,0 +1,42 @@
+// SPDX-License-Identifier: BSD-3-Clause
+/*
+ * linux/net/sunrpc/auth_gss/auth_gss_internal.h
+ *
+ * Internal definitions for RPCSEC_GSS client authentication
+ *
+ * Copyright (c) 2000 The Regents of the University of Michigan.
+ * All rights reserved.
+ *
+ */
+#include <linux/err.h>
+#include <linux/string.h>
+#include <linux/sunrpc/xdr.h>
+
+static inline const void *
+simple_get_bytes(const void *p, const void *end, void *res, size_t len)
+{
+ const void *q = (const void *)((const char *)p + len);
+ if (unlikely(q > end || q < p))
+ return ERR_PTR(-EFAULT);
+ memcpy(res, p, len);
+ return q;
+}
+
+static inline const void *
+simple_get_netobj(const void *p, const void *end, struct xdr_netobj *dest)
+{
+ const void *q;
+ unsigned int len;
+
+ p = simple_get_bytes(p, end, &len, sizeof(len));
+ if (IS_ERR(p))
+ return p;
+ q = (const void *)((const char *)p + len);
+ if (unlikely(q > end || q < p))
+ return ERR_PTR(-EFAULT);
+ dest->data = kmemdup(p, len, GFP_NOFS);
+ if (unlikely(dest->data == NULL))
+ return ERR_PTR(-ENOMEM);
+ dest->len = len;
+ return q;
+}
diff --git a/net/sunrpc/auth_gss/gss_krb5_mech.c b/net/sunrpc/auth_gss/gss_krb5_mech.c
index ae9acf3a7389..1c092b05c2bb 100644
--- a/net/sunrpc/auth_gss/gss_krb5_mech.c
+++ b/net/sunrpc/auth_gss/gss_krb5_mech.c
@@ -21,6 +21,8 @@
#include <linux/sunrpc/xdr.h>
#include <linux/sunrpc/gss_krb5_enctypes.h>
+#include "auth_gss_internal.h"
+
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_AUTH
#endif
@@ -143,35 +145,6 @@
return NULL;
}
-static const void *
-simple_get_bytes(const void *p, const void *end, void *res, int len)
-{
- const void *q = (const void *)((const char *)p + len);
- if (unlikely(q > end || q < p))
- return ERR_PTR(-EFAULT);
- memcpy(res, p, len);
- return q;
-}
-
-static const void *
-simple_get_netobj(const void *p, const void *end, struct xdr_netobj *res)
-{
- const void *q;
- unsigned int len;
-
- p = simple_get_bytes(p, end, &len, sizeof(len));
- if (IS_ERR(p))
- return p;
- q = (const void *)((const char *)p + len);
- if (unlikely(q > end || q < p))
- return ERR_PTR(-EFAULT);
- res->data = kmemdup(p, len, GFP_NOFS);
- if (unlikely(res->data == NULL))
- return ERR_PTR(-ENOMEM);
- res->len = len;
- return q;
-}
-
static inline const void *
get_key(const void *p, const void *end,
struct krb5_ctx *ctx, struct crypto_sync_skcipher **res)
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread* [PATCH v3 2/2] SUNRPC: Handle 0 length opaque XDR object data properly
2021-01-21 21:17 [PATCH v3 0/2] Fix crash in trace_rpcgss_context due to 0-length acceptor Dave Wysochanski
2021-01-21 21:17 ` [PATCH v3 1/2] SUNRPC: Move simple_get_bytes and simple_get_netobj into private header Dave Wysochanski
@ 2021-01-21 21:17 ` Dave Wysochanski
1 sibling, 0 replies; 3+ messages in thread
From: Dave Wysochanski @ 2021-01-21 21:17 UTC (permalink / raw)
To: Trond Myklebust, Anna Schumaker; +Cc: linux-nfs
When handling an auth_gss downcall, it's possible to get 0-length
opaque object for the acceptor. In the case of a 0-length XDR
object, make sure simple_get_netobj() fills in dest->data = NULL,
and does not continue to kmemdup() which will set
dest->data = ZERO_SIZE_PTR for the acceptor.
The trace event code can handle NULL but not ZERO_SIZE_PTR for a
string, and so without this patch the rpcgss_context trace event
will crash the kernel as follows:
[ 162.887992] BUG: kernel NULL pointer dereference, address: 0000000000000010
[ 162.898693] #PF: supervisor read access in kernel mode
[ 162.900830] #PF: error_code(0x0000) - not-present page
[ 162.902940] PGD 0 P4D 0
[ 162.904027] Oops: 0000 [#1] SMP PTI
[ 162.905493] CPU: 4 PID: 4321 Comm: rpc.gssd Kdump: loaded Not tainted 5.10.0 #133
[ 162.908548] Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
[ 162.910978] RIP: 0010:strlen+0x0/0x20
[ 162.912505] Code: 48 89 f9 74 09 48 83 c1 01 80 39 00 75 f7 31 d2 44 0f b6 04 16 44 88 04 11 48 83 c2 01 45 84 c0 75 ee c3 0f 1f 80 00 00 00 00 <80> 3f 00 74 10 48 89 f8 48 83 c0 01 80 38 00 75 f7 48 29 f8 c3 31
[ 162.920101] RSP: 0018:ffffaec900c77d90 EFLAGS: 00010202
[ 162.922263] RAX: 0000000000000000 RBX: 0000000000000000 RCX: 00000000fffde697
[ 162.925158] RDX: 000000000000002f RSI: 0000000000000080 RDI: 0000000000000010
[ 162.928073] RBP: 0000000000000010 R08: 0000000000000e10 R09: 0000000000000000
[ 162.930976] R10: ffff8e698a590cb8 R11: 0000000000000001 R12: 0000000000000e10
[ 162.933883] R13: 00000000fffde697 R14: 000000010034d517 R15: 0000000000070028
[ 162.936777] FS: 00007f1e1eb93700(0000) GS:ffff8e6ab7d00000(0000) knlGS:0000000000000000
[ 162.940067] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 162.942417] CR2: 0000000000000010 CR3: 0000000104eba000 CR4: 00000000000406e0
[ 162.945300] Call Trace:
[ 162.946428] trace_event_raw_event_rpcgss_context+0x84/0x140 [auth_rpcgss]
[ 162.949308] ? __kmalloc_track_caller+0x35/0x5a0
[ 162.951224] ? gss_pipe_downcall+0x3a3/0x6a0 [auth_rpcgss]
[ 162.953484] gss_pipe_downcall+0x585/0x6a0 [auth_rpcgss]
[ 162.955953] rpc_pipe_write+0x58/0x70 [sunrpc]
[ 162.957849] vfs_write+0xcb/0x2c0
[ 162.959264] ksys_write+0x68/0xe0
[ 162.960706] do_syscall_64+0x33/0x40
[ 162.962238] entry_SYSCALL_64_after_hwframe+0x44/0xa9
[ 162.964346] RIP: 0033:0x7f1e1f1e57df
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
---
net/sunrpc/auth_gss/auth_gss_internal.h | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/net/sunrpc/auth_gss/auth_gss_internal.h b/net/sunrpc/auth_gss/auth_gss_internal.h
index c5603242b54b..f6d9631bd9d0 100644
--- a/net/sunrpc/auth_gss/auth_gss_internal.h
+++ b/net/sunrpc/auth_gss/auth_gss_internal.h
@@ -34,9 +34,12 @@
q = (const void *)((const char *)p + len);
if (unlikely(q > end || q < p))
return ERR_PTR(-EFAULT);
- dest->data = kmemdup(p, len, GFP_NOFS);
- if (unlikely(dest->data == NULL))
- return ERR_PTR(-ENOMEM);
+ if (len) {
+ dest->data = kmemdup(p, len, GFP_NOFS);
+ if (unlikely(dest->data == NULL))
+ return ERR_PTR(-ENOMEM);
+ } else
+ dest->data = NULL;
dest->len = len;
return q;
}
--
1.8.3.1
^ permalink raw reply related [flat|nested] 3+ messages in thread