From dec24b3b339487e58ce2da2875e9ee0316cc7e70 Mon Sep 17 00:00:00 2001 From: Kees Cook Date: Tue, 20 Jun 2023 12:42:38 -0700 Subject: [PATCH] net: wwan: iosm: Convert single instance struct member to flexible array 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 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 Cc: Bagas Sanjaya Cc: Intel Corporation Cc: Loic Poulain Cc: Sergey Ryazanov Cc: Johannes Berg Cc: "David S. Miller" Cc: Eric Dumazet Cc: Jakub Kicinski Cc: Paolo Abeni Cc: "Gustavo A. R. Silva" Cc: netdev@vger.kernel.org Signed-off-by: Kees Cook Reviewed-by: Gustavo A. R. Silva Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20230620194234.never.023-kees@kernel.org Signed-off-by: Paolo Abeni --- drivers/net/wwan/iosm/iosm_ipc_mux_codec.c | 15 ++++++--------- drivers/net/wwan/iosm/iosm_ipc_mux_codec.h | 2 +- 2 files changed, 7 insertions(+), 10 deletions(-) diff --git a/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c index d6b166f..bff46f7 100644 --- a/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c +++ b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.c @@ -626,14 +626,12 @@ static void mux_dl_adb_decode(struct iosm_mux *ipc_mux, if (adth->signature != cpu_to_le32(IOSM_AGGR_MUX_SIG_ADTH)) goto adb_decode_err; - if (le16_to_cpu(adth->table_length) < (sizeof(struct mux_adth) - - sizeof(struct mux_adth_dg))) + if (le16_to_cpu(adth->table_length) < sizeof(struct mux_adth)) goto adb_decode_err; /* Calculate the number of datagrams. */ nr_of_dg = (le16_to_cpu(adth->table_length) - - sizeof(struct mux_adth) + - sizeof(struct mux_adth_dg)) / + sizeof(struct mux_adth)) / sizeof(struct mux_adth_dg); /* Is the datagram table empty ? */ @@ -649,7 +647,7 @@ static void mux_dl_adb_decode(struct iosm_mux *ipc_mux, } /* New aggregated datagram table. */ - dg = &adth->dg; + dg = adth->dg; if (mux_dl_process_dg(ipc_mux, adbh, dg, skb, if_id, nr_of_dg) < 0) goto adb_decode_err; @@ -849,7 +847,7 @@ static void ipc_mux_ul_encode_adth(struct iosm_mux *ipc_mux, adth->if_id = i; adth->table_length = cpu_to_le16(adth_dg_size); adth_dg_size -= offsetof(struct mux_adth, dg); - memcpy(&adth->dg, ul_adb->dg[i], adth_dg_size); + memcpy(adth->dg, ul_adb->dg[i], adth_dg_size); ul_adb->if_cnt++; } @@ -1426,14 +1424,13 @@ static int ipc_mux_get_payload_from_adb(struct iosm_mux *ipc_mux, if (adth->signature == cpu_to_le32(IOSM_AGGR_MUX_SIG_ADTH)) { nr_of_dg = (le16_to_cpu(adth->table_length) - - sizeof(struct mux_adth) + - sizeof(struct mux_adth_dg)) / + sizeof(struct mux_adth)) / sizeof(struct mux_adth_dg); if (nr_of_dg <= 0) return payload_size; - dg = &adth->dg; + dg = adth->dg; for (i = 0; i < nr_of_dg; i++, dg++) { if (le32_to_cpu(dg->datagram_index) < diff --git a/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h index 5d4e3b8..f8df88f 100644 --- a/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h +++ b/drivers/net/wwan/iosm/iosm_ipc_mux_codec.h @@ -161,7 +161,7 @@ struct mux_adth { u8 opt_ipv4v6; __le32 next_table_index; __le32 reserved2; - struct mux_adth_dg dg; + struct mux_adth_dg dg[]; }; /** -- 2.7.4