usb: gadget: f_fs: fix NULL pointer dereference when there are no strings

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commit f0688c8b81 upstream.

If the descriptors do not need any strings and user space sends empty
set of strings, the ffs->stringtabs field remains NULL.  Thus
*ffs->stringtabs in functionfs_bind leads to a NULL pointer
dereferenece.

The bug was introduced by commit [fd7c9a007f: “use usb_string_ids_n()”].

While at it, remove double initialisation of lang local variable in
that function.

ffs->strings_count does not need to be checked in any way since in
the above scenario it will remain zero and usb_string_ids_n() is
a no-operation when colled with 0 argument.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

This commit is contained in:

Michal Nazarewicz 2014-06-17 17:47:41 +02:00 • committed by Greg Kroah-Hartman

parent 40c409dced

commit 7416376c48

1 changed files with 7 additions and 5 deletions

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drivers/usb/gadget/f_fs.c

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