Revision dec24b3b339487e58ce2da2875e9ee0316cc7e70 authored by Kees Cook on 20 June 2023, 19:42:38 UTC, committed by Paolo Abeni on 22 June 2023, 09:27:47 UTC
struct mux_adth actually ends with multiple struct mux_adth_dg members.
This is seen both in the comments about the member:

/**
 * struct mux_adth - Structure of the Aggregated Datagram Table Header.
 ...
 * @dg:		datagramm table with variable length
 */

and in the preparation for populating it:

                        adth_dg_size = offsetof(struct mux_adth, dg) +
                                        ul_adb->dg_count[i] * sizeof(*dg);
			...
                        adth_dg_size -= offsetof(struct mux_adth, dg);
                        memcpy(&adth->dg, ul_adb->dg[i], adth_dg_size);

This was reported as a run-time false positive warning:

memcpy: detected field-spanning write (size 16) of single field "&adth->dg" at drivers/net/wwan/iosm/iosm_ipc_mux_codec.c:852 (size 8)

Adjust the struct mux_adth definition and associated sizeof() math; no binary
output differences are observed in the resulting object file.

Reported-by: Florian Klink <flokli@flokli.de>
Closes: https://lore.kernel.org/lkml/dbfa25f5-64c8-5574-4f5d-0151ba95d232@gmail.com/
Fixes: 1f52d7b62285 ("net: wwan: iosm: Enable M.2 7360 WWAN card support")
Cc: M Chetan Kumar <m.chetan.kumar@intel.com>
Cc: Bagas Sanjaya <bagasdotme@gmail.com>
Cc: Intel Corporation <linuxwwan@intel.com>
Cc: Loic Poulain <loic.poulain@linaro.org>
Cc: Sergey Ryazanov <ryazanov.s.a@gmail.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Jakub Kicinski <kuba@kernel.org>
Cc: Paolo Abeni <pabeni@redhat.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: netdev@vger.kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230620194234.never.023-kees@kernel.org
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
1 parent 2174a08
Raw File
muldi3.c
// SPDX-License-Identifier: GPL-2.0-or-later
/*
 */

#include <linux/export.h>
#include <linux/libgcc.h>

#define W_TYPE_SIZE 32

#define __ll_B ((unsigned long) 1 << (W_TYPE_SIZE / 2))
#define __ll_lowpart(t) ((unsigned long) (t) & (__ll_B - 1))
#define __ll_highpart(t) ((unsigned long) (t) >> (W_TYPE_SIZE / 2))

/* If we still don't have umul_ppmm, define it using plain C.  */
#if !defined(umul_ppmm)
#define umul_ppmm(w1, w0, u, v)						\
	do {								\
		unsigned long __x0, __x1, __x2, __x3;			\
		unsigned short __ul, __vl, __uh, __vh;			\
									\
		__ul = __ll_lowpart(u);					\
		__uh = __ll_highpart(u);				\
		__vl = __ll_lowpart(v);					\
		__vh = __ll_highpart(v);				\
									\
		__x0 = (unsigned long) __ul * __vl;			\
		__x1 = (unsigned long) __ul * __vh;			\
		__x2 = (unsigned long) __uh * __vl;			\
		__x3 = (unsigned long) __uh * __vh;			\
									\
		__x1 += __ll_highpart(__x0); /* this can't give carry */\
		__x1 += __x2; /* but this indeed can */			\
		if (__x1 < __x2) /* did we get it? */			\
		__x3 += __ll_B; /* yes, add it in the proper pos */	\
									\
		(w1) = __x3 + __ll_highpart(__x1);			\
		(w0) = __ll_lowpart(__x1) * __ll_B + __ll_lowpart(__x0);\
	} while (0)
#endif

#if !defined(__umulsidi3)
#define __umulsidi3(u, v) ({				\
	DWunion __w;					\
	umul_ppmm(__w.s.high, __w.s.low, u, v);		\
	__w.ll;						\
	})
#endif

long long notrace __muldi3(long long u, long long v)
{
	const DWunion uu = {.ll = u};
	const DWunion vv = {.ll = v};
	DWunion w = {.ll = __umulsidi3(uu.s.low, vv.s.low)};

	w.s.high += ((unsigned long) uu.s.low * (unsigned long) vv.s.high
		+ (unsigned long) uu.s.high * (unsigned long) vv.s.low);

	return w.ll;
}
EXPORT_SYMBOL(__muldi3);
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