[Devel] [patch rh7] RDS: verify the underlying transport exists before creating a connection

Vasily Averin vvs at virtuozzo.com
Tue Sep 15 07:08:13 PDT 2015


fix for CVE-2015-6937

commit 74e98eb085889b0d2d4908f59f6e00026063014f
Author: Sasha Levin <sasha.levin at oracle.com>
Date:   Tue Sep 8 10:53:40 2015 -0400

    RDS: verify the underlying transport exists before creating a connection
    
    There was no verification that an underlying transport exists when creating
    a connection, this would cause dereferencing a NULL ptr.
    
    It might happen on sockets that weren't properly bound before attempting to
    send a message, which will cause a NULL ptr deref:
    
    [135546.047719] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN
    [135546.051270] Modules linked in:
    [135546.051781] CPU: 4 PID: 15650 Comm: trinity-c4 Not tainted 4.2.0-next-20150902-sasha-00041-gbaa1222-dirty #2527
    [135546.053217] task: ffff8800835bc000 ti: ffff8800bc708000 task.ti: ffff8800bc708000
    [135546.054291] RIP: __rds_conn_create (net/rds/connection.c:194)
    [135546.055666] RSP: 0018:ffff8800bc70fab0  EFLAGS: 00010202
    [135546.056457] RAX: dffffc0000000000 RBX: 0000000000000f2c RCX: ffff8800835bc000
    [135546.057494] RDX: 0000000000000007 RSI: ffff8800835bccd8 RDI: 0000000000000038
    [135546.058530] RBP: ffff8800bc70fb18 R08: 0000000000000001 R09: 0000000000000000
    [135546.059556] R10: ffffed014d7a3a23 R11: ffffed014d7a3a21 R12: 0000000000000000
    [135546.060614] R13: 0000000000000001 R14: ffff8801ec3d0000 R15: 0000000000000000
    [135546.061668] FS:  00007faad4ffb700(0000) GS:ffff880252000000(0000) knlGS:0000000000000000
    [135546.062836] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
    [135546.063682] CR2: 000000000000846a CR3: 000000009d137000 CR4: 00000000000006a0
    [135546.064723] Stack:
    [135546.065048]  ffffffffafe2055c ffffffffafe23fc1 ffffed00493097bf ffff8801ec3d0008
    [135546.066247]  0000000000000000 00000000000000d0 0000000000000000 ac194a24c0586342
    [135546.067438]  1ffff100178e1f78 ffff880320581b00 ffff8800bc70fdd0 ffff880320581b00
    [135546.068629] Call Trace:
    [135546.069028] ? __rds_conn_create (include/linux/rcupdate.h:856 net/rds/connection.c:134)
    [135546.069989] ? rds_message_copy_from_user (net/rds/message.c:298)
    [135546.071021] rds_conn_create_outgoing (net/rds/connection.c:278)
    [135546.071981] rds_sendmsg (net/rds/send.c:1058)
    [135546.072858] ? perf_trace_lock (include/trace/events/lock.h:38)
    [135546.073744] ? lockdep_init (kernel/locking/lockdep.c:3298)
    [135546.074577] ? rds_send_drop_to (net/rds/send.c:976)
    [135546.075508] ? __might_fault (./arch/x86/include/asm/current.h:14 mm/memory.c:3795)
    [135546.076349] ? __might_fault (mm/memory.c:3795)
    [135546.077179] ? rds_send_drop_to (net/rds/send.c:976)
    [135546.078114] sock_sendmsg (net/socket.c:611 net/socket.c:620)
    [135546.078856] SYSC_sendto (net/socket.c:1657)
    [135546.079596] ? SYSC_connect (net/socket.c:1628)
    [135546.080510] ? trace_dump_stack (kernel/trace/trace.c:1926)
    [135546.081397] ? ring_buffer_unlock_commit (kernel/trace/ring_buffer.c:2479 kernel/trace/ring_buffer.c:2558 kernel/trace/ring_buffer.c:2674)
    [135546.082390] ? trace_buffer_unlock_commit (kernel/trace/trace.c:1749)
    [135546.083410] ? trace_event_raw_event_sys_enter (include/trace/events/syscalls.h:16)
    [135546.084481] ? do_audit_syscall_entry (include/trace/events/syscalls.h:16)
    [135546.085438] ? trace_buffer_unlock_commit (kernel/trace/trace.c:1749)
    [135546.085515] rds_ib_laddr_check(): addr 36.74.25.172 ret -99 node type -1
    
    Acked-by: Santosh Shilimkar <santosh.shilimkar at oracle.com>
    Signed-off-by: Sasha Levin <sasha.levin at oracle.com>
    Signed-off-by: David S. Miller <davem at davemloft.net>

Signed-off-by: Vasily Averin <vvs at virtuozzo.com>
-------------- next part --------------
fix for CVE-2015-6937

commit 74e98eb085889b0d2d4908f59f6e00026063014f
Author: Sasha Levin <sasha.levin at oracle.com>
Date:   Tue Sep 8 10:53:40 2015 -0400

    RDS: verify the underlying transport exists before creating a connection
    
    There was no verification that an underlying transport exists when creating
    a connection, this would cause dereferencing a NULL ptr.
    
    It might happen on sockets that weren't properly bound before attempting to
    send a message, which will cause a NULL ptr deref:
    
    [135546.047719] kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC KASAN
    [135546.051270] Modules linked in:
    [135546.051781] CPU: 4 PID: 15650 Comm: trinity-c4 Not tainted 4.2.0-next-20150902-sasha-00041-gbaa1222-dirty #2527
    [135546.053217] task: ffff8800835bc000 ti: ffff8800bc708000 task.ti: ffff8800bc708000
    [135546.054291] RIP: __rds_conn_create (net/rds/connection.c:194)
    [135546.055666] RSP: 0018:ffff8800bc70fab0  EFLAGS: 00010202
    [135546.056457] RAX: dffffc0000000000 RBX: 0000000000000f2c RCX: ffff8800835bc000
    [135546.057494] RDX: 0000000000000007 RSI: ffff8800835bccd8 RDI: 0000000000000038
    [135546.058530] RBP: ffff8800bc70fb18 R08: 0000000000000001 R09: 0000000000000000
    [135546.059556] R10: ffffed014d7a3a23 R11: ffffed014d7a3a21 R12: 0000000000000000
    [135546.060614] R13: 0000000000000001 R14: ffff8801ec3d0000 R15: 0000000000000000
    [135546.061668] FS:  00007faad4ffb700(0000) GS:ffff880252000000(0000) knlGS:0000000000000000
    [135546.062836] CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
    [135546.063682] CR2: 000000000000846a CR3: 000000009d137000 CR4: 00000000000006a0
    [135546.064723] Stack:
    [135546.065048]  ffffffffafe2055c ffffffffafe23fc1 ffffed00493097bf ffff8801ec3d0008
    [135546.066247]  0000000000000000 00000000000000d0 0000000000000000 ac194a24c0586342
    [135546.067438]  1ffff100178e1f78 ffff880320581b00 ffff8800bc70fdd0 ffff880320581b00
    [135546.068629] Call Trace:
    [135546.069028] ? __rds_conn_create (include/linux/rcupdate.h:856 net/rds/connection.c:134)
    [135546.069989] ? rds_message_copy_from_user (net/rds/message.c:298)
    [135546.071021] rds_conn_create_outgoing (net/rds/connection.c:278)
    [135546.071981] rds_sendmsg (net/rds/send.c:1058)
    [135546.072858] ? perf_trace_lock (include/trace/events/lock.h:38)
    [135546.073744] ? lockdep_init (kernel/locking/lockdep.c:3298)
    [135546.074577] ? rds_send_drop_to (net/rds/send.c:976)
    [135546.075508] ? __might_fault (./arch/x86/include/asm/current.h:14 mm/memory.c:3795)
    [135546.076349] ? __might_fault (mm/memory.c:3795)
    [135546.077179] ? rds_send_drop_to (net/rds/send.c:976)
    [135546.078114] sock_sendmsg (net/socket.c:611 net/socket.c:620)
    [135546.078856] SYSC_sendto (net/socket.c:1657)
    [135546.079596] ? SYSC_connect (net/socket.c:1628)
    [135546.080510] ? trace_dump_stack (kernel/trace/trace.c:1926)
    [135546.081397] ? ring_buffer_unlock_commit (kernel/trace/ring_buffer.c:2479 kernel/trace/ring_buffer.c:2558 kernel/trace/ring_buffer.c:2674)
    [135546.082390] ? trace_buffer_unlock_commit (kernel/trace/trace.c:1749)
    [135546.083410] ? trace_event_raw_event_sys_enter (include/trace/events/syscalls.h:16)
    [135546.084481] ? do_audit_syscall_entry (include/trace/events/syscalls.h:16)
    [135546.085438] ? trace_buffer_unlock_commit (kernel/trace/trace.c:1749)
    [135546.085515] rds_ib_laddr_check(): addr 36.74.25.172 ret -99 node type -1
    
    Acked-by: Santosh Shilimkar <santosh.shilimkar at oracle.com>
    Signed-off-by: Sasha Levin <sasha.levin at oracle.com>
    Signed-off-by: David S. Miller <davem at davemloft.net>

Signed-off-by: Vasily Averin <vvs at virtuozzo.com>

diff --git a/net/rds/connection.c b/net/rds/connection.c
index 9b2de5e..49adeef 100644
--- a/net/rds/connection.c
+++ b/net/rds/connection.c
@@ -190,6 +190,12 @@ new_conn:
 		}
 	}
 
+	if (trans == NULL) {
+		kmem_cache_free(rds_conn_slab, conn);
+		conn = ERR_PTR(-ENODEV);
+		goto out;
+	}
+
 	conn->c_trans = trans;
 
 	ret = trans->conn_alloc(conn, gfp);


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