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Commit b0a0ebfe authored by Udipto Goswami's avatar Udipto Goswami Committed by Greg Kroah-Hartman
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usb: f_fs: Clear OS Extended descriptor counts to zero in ffs_data_reset() 



commit 1c2e54fbf1da5e5445a0ab132c862b02ccd8d230 upstream.

For userspace functions using OS Descriptors, if a function also supplies
Extended Property descriptors currently the counts and lengths stored in
the ms_os_descs_ext_prop_{count,name_len,data_len} variables are not
getting reset to 0 during an unbind or when the epfiles are closed. If
the same function is re-bound and the descriptors are re-written, this
results in those count/length variables to monotonically increase
causing the VLA allocation in _ffs_func_bind() to grow larger and larger
at each bind/unbind cycle and eventually fail to allocate.

Fix this by clearing the ms_os_descs_ext_prop count & lengths to 0 in
ffs_data_reset().

Fixes: f0175ab5 ("usb: gadget: f_fs: OS descriptors support")
Cc: stable@vger.kernel.org
Signed-off-by: default avatarUdipto Goswami <ugoswami@codeaurora.org>
Signed-off-by: default avatarSriharsha Allenki <sallenki@codeaurora.org>
Reviewed-by: default avatarManu Gautam <mgautam@codeaurora.org>
Link: https://lore.kernel.org/r/20200402044521.9312-1-sallenki@codeaurora.org


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent dbee0a82

drivers/usb/gadget/function/f_fs.c

+4 −0
Original line number Diff line number Diff line
@@ -1737,6 +1737,10 @@ static void ffs_data_reset(struct ffs_data *ffs) 
	ffs->state = FFS_READ_DESCRIPTORS;

	ffs->setup_state = FFS_NO_SETUP;

	ffs->flags = 0;



	ffs->ms_os_descs_ext_prop_count = 0;

	ffs->ms_os_descs_ext_prop_name_len = 0;

	ffs->ms_os_descs_ext_prop_data_len = 0;

}