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authorJulia Lawall <julia@diku.dk>2008-05-12 18:43:46 -0400
committerDavid S. Miller <davem@davemloft.net>2008-05-12 18:43:46 -0400
commit5dc474d6b3ba19df7d491d4eabd9fb7a0c1c2423 (patch)
tree0f508a88537c0feb4edb6669bb54d12daa543c1b /drivers/net/pppol2tp.c
parent4951704b4e23d71b99ac933d8e6993bc6225ac13 (diff)
pppol2tp: Remove null pointer dereference.
If session is NULL, it is not possible to access its name field. So I have split apart the printing of the error message to drop the printing of the name field in this case. The macro PRINTK actually only evaluates its arguments starting with the third one if the bitwise conjunction of the first two is non-zero. Normally, this conjunction would only be non-zero if debugging mode were turned on, but when session is NULL, the first argument in both the old and new code is -1, and thus the bitwise conjunction is true. Perhaps a different strategy is desired, such as using tunnel->debug, which session->debug is initialized to, but tunnel can also be NULL, so this does not completely solve the problem. This problem was found using the following semantic match (http://www.emn.fr/x-info/coccinelle/) // <smpl> @@ expression E, E1; identifier f; statement S1,S2,S3; @@ * if (E == NULL) { ... when != if (E == NULL) S1 else S2 when != E = E1 * E->f ... when any return ...; } else S3 // </smpl> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/net/pppol2tp.c')
-rw-r--r--drivers/net/pppol2tp.c13
1 files changed, 10 insertions, 3 deletions
diff --git a/drivers/net/pppol2tp.c b/drivers/net/pppol2tp.c
index 244d7830c92a..79359919335b 100644
--- a/drivers/net/pppol2tp.c
+++ b/drivers/net/pppol2tp.c
@@ -1621,9 +1621,16 @@ out_no_ppp:
1621end: 1621end:
1622 release_sock(sk); 1622 release_sock(sk);
1623 1623
1624 if (error != 0) 1624 if (error != 0) {
1625 PRINTK(session ? session->debug : -1, PPPOL2TP_MSG_CONTROL, KERN_WARNING, 1625 if (session)
1626 "%s: connect failed: %d\n", session->name, error); 1626 PRINTK(session->debug,
1627 PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1628 "%s: connect failed: %d\n",
1629 session->name, error);
1630 else
1631 PRINTK(-1, PPPOL2TP_MSG_CONTROL, KERN_WARNING,
1632 "connect failed: %d\n", error);
1633 }
1627 1634
1628 return error; 1635 return error;
1629} 1636}