ppp: ensure file->private_data can't be overridden

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[ Upstream commit e8e56ffd9d ]

Locking ppp_mutex must be done before dereferencing file->private_data,
otherwise it could be modified before ppp_unattached_ioctl() takes the
lock. This could lead ppp_unattached_ioctl() to override ->private_data,
thus leaking reference to the ppp_file previously pointed to.

v2: lock all ppp_ioctl() instead of just checking private_data in
    ppp_unattached_ioctl(), to avoid ambiguous behaviour.

Fixes: f3ff8a4d80 ("ppp: push BKL down into the driver")
Signed-off-by: Guillaume Nault <g.nault@alphalink.fr>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Guillaume Nault 2016-03-14 21:17:16 +01:00 • committed by Greg Kroah-Hartman

parent a317579bb6

commit 029464a380

1 changed files with 17 additions and 14 deletions

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drivers/net/ppp/ppp_generic.c

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