On 9/17/2024 8:08 AM, Alper Nebi Yasak wrote: > Replace one-element array with a flexible-array member in `struct > mwifiex_ie_types_wildcard_ssid_params` to fix the following warning > on a MT8173 Chromebook (mt8173-elm-hana): > > [ 356.775250] ------------[ cut here ]------------ > [ 356.784543] memcpy: detected field-spanning write (size 6) of single field "wildcard_ssid_tlv->ssid" at drivers/net/wireless/marvell/mwifiex/scan.c:904 (size 1) > [ 356.813403] WARNING: CPU: 3 PID: 742 at drivers/net/wireless/marvell/mwifiex/scan.c:904 mwifiex_scan_networks+0x4fc/0xf28 [mwifiex] > > The "(size 6)" above is exactly the length of the SSID of the network > this device was connected to. The source of the warning looks like: > > ssid_len = user_scan_in->ssid_list[i].ssid_len; > [...] > memcpy(wildcard_ssid_tlv->ssid, > user_scan_in->ssid_list[i].ssid, ssid_len); > > Also adjust a #define that uses sizeof() on this struct to keep the > value same as before. > > Signed-off-by: Alper Nebi Yasak <alpernebiyasak@xxxxxxxxx> > --- > I found these relevant patches that modify other such arrays, where the > second one removes a -1 from some sizeof() calculation: > > https://lore.kernel.org/lkml/Y9xkECG3uTZ6T1dN@work/T/#u > https://lore.kernel.org/lkml/ZsZa5xRcsLq9D+RX@elsanto/T/#u > > So I think we need the +1 to keep things same. But it appears to work > fine without it, so I'm not sure. Maybe it should've had a -1 before > that I would remove with this? I think the original code was incorrect and was allocating too much memory. I do not think WILDCARD_SSID_TLV_MAX_SIZE requires modification. > > drivers/net/wireless/marvell/mwifiex/fw.h | 2 +- > drivers/net/wireless/marvell/mwifiex/scan.c | 2 +- > 2 files changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h > index d03129d5d24e..4a96281792cc 100644 > --- a/drivers/net/wireless/marvell/mwifiex/fw.h > +++ b/drivers/net/wireless/marvell/mwifiex/fw.h > @@ -875,7 +875,7 @@ struct mwifiex_ietypes_chanstats { > struct mwifiex_ie_types_wildcard_ssid_params { > struct mwifiex_ie_types_header header; > u8 max_ssid_length; > - u8 ssid[1]; > + u8 ssid[]; > } __packed; > > #define TSF_DATA_SIZE 8 > diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c > index cab889af4c4a..50af78ee935b 100644 > --- a/drivers/net/wireless/marvell/mwifiex/scan.c > +++ b/drivers/net/wireless/marvell/mwifiex/scan.c > @@ -32,7 +32,7 @@ > #define WILDCARD_SSID_TLV_MAX_SIZE \ > (MWIFIEX_MAX_SSID_LIST_LENGTH * \ > (sizeof(struct mwifiex_ie_types_wildcard_ssid_params) \ > - + IEEE80211_MAX_SSID_LEN)) > + + IEEE80211_MAX_SSID_LEN + 1)) > > /* Maximum memory needed for a mwifiex_scan_cmd_config with all TLVs at max */ > #define MAX_SCAN_CFG_ALLOC (sizeof(struct mwifiex_scan_cmd_config) \ > > base-commit: 4f3e012d4cfd1d9bf837870c961f462ca9f23ebe
