On Thu, Sep 12, 2024 at 01:01:21AM +0200, Ben Hutchings wrote: > iwlegacy uses command buffers with a payload size of 320 > bytes (default) or 4092 bytes (huge). The struct il_device_cmd type > describes the default buffers and there is no separate type describing > the huge buffers. > > The il_enqueue_hcmd() function works with both default and huge > buffers, and has a memcpy() to the buffer payload. The size of > this copy may exceed 320 bytes when using a huge buffer, which > now results in a run-time warning: > > memcpy: detected field-spanning write (size 1014) of single field "&out_cmd->cmd.payload" at drivers/net/wireless/intel/iwlegacy/common.c:3170 (size 320) > > To fix this: > > - Define a new struct type for huge buffers, with a correctly sized > payload field > - When using a huge buffer in il_enqueue_hcmd(), cast the command > buffer pointer to that type when looking up the payload field > > Reported-by: Martin-Éric Racine <martin-eric.racine@xxxxxx> > References: https://bugs.debian.org/1062421 > References: https://bugzilla.kernel.org/show_bug.cgi?id=219124 > Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> > Fixes: 54d9469bc515 ("fortify: Add run-time WARN for cross-field memcpy()") > Tested-by: Martin-Éric Racine <martin-eric.racine@xxxxxx> > Tested-by: Brandon Nielsen <nielsenb@xxxxxxxxxxx> I proposed diffrent fix for this here: https://lore.kernel.org/linux-wireless/20240520073210.GA693073@xxxxx/ but never get feedback if it works on real HW. So I prefer this one, sice it was tested. Acked-by: Stanislaw Gruszka <stf_xl@xxxxx> Martin-Éric and Brandon, could you plase also test patch from https://lore.kernel.org/linux-wireless/Zr2gxERA3RL3EwRe@elsanto/ if it does not break the driver? Thanks Stanislaw > --- > drivers/net/wireless/intel/iwlegacy/common.c | 13 ++++++++++++- > drivers/net/wireless/intel/iwlegacy/common.h | 12 ++++++++++++ > 2 files changed, 24 insertions(+), 1 deletion(-) > > diff --git a/drivers/net/wireless/intel/iwlegacy/common.c b/drivers/net/wireless/intel/iwlegacy/common.c > index 9d33a66a49b5..4616293ec0cf 100644 > --- a/drivers/net/wireless/intel/iwlegacy/common.c > +++ b/drivers/net/wireless/intel/iwlegacy/common.c > @@ -3122,6 +3122,7 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd) > struct il_cmd_meta *out_meta; > dma_addr_t phys_addr; > unsigned long flags; > + u8 *out_payload; > u32 idx; > u16 fix_size; > > @@ -3157,6 +3158,16 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd) > out_cmd = txq->cmd[idx]; > out_meta = &txq->meta[idx]; > > + /* The payload is in the same place in regular and huge > + * command buffers, but we need to let the compiler know when > + * we're using a larger payload buffer to avoid "field- > + * spanning write" warnings at run-time for huge commands. > + */ > + if (cmd->flags & CMD_SIZE_HUGE) > + out_payload = ((struct il_device_cmd_huge *)out_cmd)->cmd.payload; > + else > + out_payload = out_cmd->cmd.payload; > + > if (WARN_ON(out_meta->flags & CMD_MAPPED)) { > spin_unlock_irqrestore(&il->hcmd_lock, flags); > return -ENOSPC; > @@ -3170,7 +3181,7 @@ il_enqueue_hcmd(struct il_priv *il, struct il_host_cmd *cmd) > out_meta->callback = cmd->callback; > > out_cmd->hdr.cmd = cmd->id; > - memcpy(&out_cmd->cmd.payload, cmd->data, cmd->len); > + memcpy(out_payload, cmd->data, cmd->len); > > /* At this point, the out_cmd now has all of the incoming cmd > * information */ > diff --git a/drivers/net/wireless/intel/iwlegacy/common.h b/drivers/net/wireless/intel/iwlegacy/common.h > index 69687fcf963f..027dae5619a3 100644 > --- a/drivers/net/wireless/intel/iwlegacy/common.h > +++ b/drivers/net/wireless/intel/iwlegacy/common.h > @@ -560,6 +560,18 @@ struct il_device_cmd { > > #define TFD_MAX_PAYLOAD_SIZE (sizeof(struct il_device_cmd)) > > +/** > + * struct il_device_cmd_huge > + * > + * For use when sending huge commands. > + */ > +struct il_device_cmd_huge { > + struct il_cmd_header hdr; /* uCode API */ > + union { > + u8 payload[IL_MAX_CMD_SIZE - sizeof(struct il_cmd_header)]; > + } __packed cmd; > +} __packed; > + > struct il_host_cmd { > const void *data; > unsigned long reply_page;
