| Message ID | 83b0388403a61c01fad8d638db40b4245666ff53.1617226664.git.gustavoars@kernel.org |
|---|---|
| State | Superseded |
| Headers | show |
| Series | wl3501_cs: Fix out-of-bounds warnings | expand |
On Wed, Mar 31, 2021 at 04:45:34PM -0500, Gustavo A. R. Silva wrote: > Fix the following out-of-bounds warning by enclosing > some structure members into new struct req: > > arch/x86/include/asm/string_32.h:182:25: warning: '__builtin_memcpy' offset [39, 108] from the object at 'sig' is out of the bounds of referenced subobject 'beacon_period' with type 'short unsigned int' at offset 36 [-Warray-bounds] > > Refactor the code, accordingly: > > $ pahole -C wl3501_join_req drivers/net/wireless/wl3501_cs.o > struct wl3501_join_req { > u16 next_blk; /* 0 2 */ > u8 sig_id; /* 2 1 */ > u8 reserved; /* 3 1 */ > struct iw_mgmt_data_rset operational_rset; /* 4 10 */ > u16 reserved2; /* 14 2 */ > u16 timeout; /* 16 2 */ > u16 probe_delay; /* 18 2 */ > u8 timestamp[8]; /* 20 8 */ > u8 local_time[8]; /* 28 8 */ > struct { > u16 beacon_period; /* 36 2 */ > u16 dtim_period; /* 38 2 */ > u16 cap_info; /* 40 2 */ > u8 bss_type; /* 42 1 */ > u8 bssid[6]; /* 43 6 */ > struct iw_mgmt_essid_pset ssid; /* 49 34 */ > /* --- cacheline 1 boundary (64 bytes) was 19 bytes ago --- */ > struct iw_mgmt_ds_pset ds_pset; /* 83 3 */ > struct iw_mgmt_cf_pset cf_pset; /* 86 8 */ > struct iw_mgmt_ibss_pset ibss_pset; /* 94 4 */ > struct iw_mgmt_data_rset bss_basic_rset; /* 98 10 */ > } req; /* 36 72 */ This section is the same as a large portion of struct wl3501_scan_confirm: struct wl3501_scan_confirm { u16 next_blk; u8 sig_id; u8 reserved; u16 status; char timestamp[8]; char localtime[8]; from here u16 beacon_period; u16 dtim_period; u16 cap_info; u8 bss_type; u8 bssid[ETH_ALEN]; struct iw_mgmt_essid_pset ssid; struct iw_mgmt_ds_pset ds_pset; struct iw_mgmt_cf_pset cf_pset; struct iw_mgmt_ibss_pset ibss_pset; struct iw_mgmt_data_rset bss_basic_rset; through here u8 rssi; }; It seems like maybe extracting that and using it in both structures would make more sense? > > /* size: 108, cachelines: 2, members: 10 */ > /* last cacheline: 44 bytes */ > }; > > The problem is that the original code is trying to copy data into a > bunch of struct members adjacent to each other in a single call to > memcpy(). Now that a new struct _req_ enclosing all those adjacent > members is introduced, memcpy() doesn't overrun the length of > &sig.beacon_period, because the address of the new struct object > _req_ is used as the destination, instead. > > Also, this helps with the ongoing efforts to enable -Warray-bounds and > avoid confusing the compiler. > > Link: https://github.com/KSPP/linux/issues/109 > Reported-by: kernel test robot <lkp@intel.com> > Build-tested-by: kernel test robot <lkp@intel.com> > Link: https://lore.kernel.org/lkml/60641d9b.2eNLedOGSdcSoAV2%25lkp@intel.com/ > Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> > --- > Changes in v2: > - None. > > drivers/net/wireless/wl3501.h | 22 ++++++++++++---------- > drivers/net/wireless/wl3501_cs.c | 4 ++-- > 2 files changed, 14 insertions(+), 12 deletions(-) > > diff --git a/drivers/net/wireless/wl3501.h b/drivers/net/wireless/wl3501.h > index ef9d605d8c88..774d8cac046d 100644 > --- a/drivers/net/wireless/wl3501.h > +++ b/drivers/net/wireless/wl3501.h > @@ -389,16 +389,18 @@ struct wl3501_join_req { > u16 probe_delay; > u8 timestamp[8]; > u8 local_time[8]; > - u16 beacon_period; > - u16 dtim_period; > - u16 cap_info; > - u8 bss_type; > - u8 bssid[ETH_ALEN]; > - struct iw_mgmt_essid_pset ssid; > - struct iw_mgmt_ds_pset ds_pset; > - struct iw_mgmt_cf_pset cf_pset; > - struct iw_mgmt_ibss_pset ibss_pset; > - struct iw_mgmt_data_rset bss_basic_rset; > + struct { > + u16 beacon_period; > + u16 dtim_period; > + u16 cap_info; > + u8 bss_type; > + u8 bssid[ETH_ALEN]; > + struct iw_mgmt_essid_pset ssid; > + struct iw_mgmt_ds_pset ds_pset; > + struct iw_mgmt_cf_pset cf_pset; > + struct iw_mgmt_ibss_pset ibss_pset; > + struct iw_mgmt_data_rset bss_basic_rset; > + } req; > }; > > struct wl3501_join_confirm { > diff --git a/drivers/net/wireless/wl3501_cs.c b/drivers/net/wireless/wl3501_cs.c > index e149ef81d6cc..399d3bd2ae76 100644 > --- a/drivers/net/wireless/wl3501_cs.c > +++ b/drivers/net/wireless/wl3501_cs.c > @@ -590,7 +590,7 @@ static int wl3501_mgmt_join(struct wl3501_card *this, u16 stas) > struct wl3501_join_req sig = { > .sig_id = WL3501_SIG_JOIN_REQ, > .timeout = 10, > - .ds_pset = { > + .req.ds_pset = { > .el = { > .id = IW_MGMT_INFO_ELEMENT_DS_PARAMETER_SET, > .len = 1, > @@ -599,7 +599,7 @@ static int wl3501_mgmt_join(struct wl3501_card *this, u16 stas) > }, > }; > > - memcpy(&sig.beacon_period, &this->bss_set[stas].beacon_period, 72); > + memcpy(&sig.req, &this->bss_set[stas].beacon_period, sizeof(sig.req)); If not, then probably something like this should be added to make sure nothing unexpected happens to change structure sizes: BUILD_BUG_ON(sizeof(sig.req) != 72); > return wl3501_esbq_exec(this, &sig, sizeof(sig)); > } > > -- > 2.27.0 > -- Kees Cook
Hi all! On 4/7/21 14:02, Kees Cook wrote: > On Wed, Mar 31, 2021 at 04:45:34PM -0500, Gustavo A. R. Silva wrote: >> Fix the following out-of-bounds warning by enclosing >> some structure members into new struct req: >> >> arch/x86/include/asm/string_32.h:182:25: warning: '__builtin_memcpy' offset [39, 108] from the object at 'sig' is out of the bounds of referenced subobject 'beacon_period' with type 'short unsigned int' at offset 36 [-Warray-bounds] >> >> Refactor the code, accordingly: >> >> $ pahole -C wl3501_join_req drivers/net/wireless/wl3501_cs.o >> struct wl3501_join_req { >> u16 next_blk; /* 0 2 */ >> u8 sig_id; /* 2 1 */ >> u8 reserved; /* 3 1 */ >> struct iw_mgmt_data_rset operational_rset; /* 4 10 */ >> u16 reserved2; /* 14 2 */ >> u16 timeout; /* 16 2 */ >> u16 probe_delay; /* 18 2 */ >> u8 timestamp[8]; /* 20 8 */ >> u8 local_time[8]; /* 28 8 */ >> struct { >> u16 beacon_period; /* 36 2 */ >> u16 dtim_period; /* 38 2 */ >> u16 cap_info; /* 40 2 */ >> u8 bss_type; /* 42 1 */ >> u8 bssid[6]; /* 43 6 */ >> struct iw_mgmt_essid_pset ssid; /* 49 34 */ >> /* --- cacheline 1 boundary (64 bytes) was 19 bytes ago --- */ >> struct iw_mgmt_ds_pset ds_pset; /* 83 3 */ >> struct iw_mgmt_cf_pset cf_pset; /* 86 8 */ >> struct iw_mgmt_ibss_pset ibss_pset; /* 94 4 */ >> struct iw_mgmt_data_rset bss_basic_rset; /* 98 10 */ >> } req; /* 36 72 */ > > This section is the same as a large portion of struct wl3501_scan_confirm: > > struct wl3501_scan_confirm { > u16 next_blk; > u8 sig_id; > u8 reserved; > u16 status; > char timestamp[8]; > char localtime[8]; > > from here > u16 beacon_period; > u16 dtim_period; > u16 cap_info; > u8 bss_type; > u8 bssid[ETH_ALEN]; > struct iw_mgmt_essid_pset ssid; > struct iw_mgmt_ds_pset ds_pset; > struct iw_mgmt_cf_pset cf_pset; > struct iw_mgmt_ibss_pset ibss_pset; > struct iw_mgmt_data_rset bss_basic_rset; > through here > > u8 rssi; > }; > > It seems like maybe extracting that and using it in both structures > would make more sense? If I do this, I would therefore have to make a bunch of other changes, accordingly. I'm OK with that but I'd like to have the opinion of the maintainers on all this. So, I will go and ping them from the cover letter of this series with the hope that we can get some feedback from them. :) They have been silent for a couple of weeks now. > >> >> /* size: 108, cachelines: 2, members: 10 */ >> /* last cacheline: 44 bytes */ >> }; >> >> The problem is that the original code is trying to copy data into a >> bunch of struct members adjacent to each other in a single call to >> memcpy(). Now that a new struct _req_ enclosing all those adjacent >> members is introduced, memcpy() doesn't overrun the length of >> &sig.beacon_period, because the address of the new struct object >> _req_ is used as the destination, instead. >> >> Also, this helps with the ongoing efforts to enable -Warray-bounds and >> avoid confusing the compiler. >> >> Link: https://github.com/KSPP/linux/issues/109 >> Reported-by: kernel test robot <lkp@intel.com> >> Build-tested-by: kernel test robot <lkp@intel.com> >> Link: https://lore.kernel.org/lkml/60641d9b.2eNLedOGSdcSoAV2%25lkp@intel.com/ >> Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> >> --- >> Changes in v2: >> - None. >> >> drivers/net/wireless/wl3501.h | 22 ++++++++++++---------- >> drivers/net/wireless/wl3501_cs.c | 4 ++-- >> 2 files changed, 14 insertions(+), 12 deletions(-) >> >> diff --git a/drivers/net/wireless/wl3501.h b/drivers/net/wireless/wl3501.h >> index ef9d605d8c88..774d8cac046d 100644 >> --- a/drivers/net/wireless/wl3501.h >> +++ b/drivers/net/wireless/wl3501.h >> @@ -389,16 +389,18 @@ struct wl3501_join_req { >> u16 probe_delay; >> u8 timestamp[8]; >> u8 local_time[8]; >> - u16 beacon_period; >> - u16 dtim_period; >> - u16 cap_info; >> - u8 bss_type; >> - u8 bssid[ETH_ALEN]; >> - struct iw_mgmt_essid_pset ssid; >> - struct iw_mgmt_ds_pset ds_pset; >> - struct iw_mgmt_cf_pset cf_pset; >> - struct iw_mgmt_ibss_pset ibss_pset; >> - struct iw_mgmt_data_rset bss_basic_rset; >> + struct { >> + u16 beacon_period; >> + u16 dtim_period; >> + u16 cap_info; >> + u8 bss_type; >> + u8 bssid[ETH_ALEN]; >> + struct iw_mgmt_essid_pset ssid; >> + struct iw_mgmt_ds_pset ds_pset; >> + struct iw_mgmt_cf_pset cf_pset; >> + struct iw_mgmt_ibss_pset ibss_pset; >> + struct iw_mgmt_data_rset bss_basic_rset; >> + } req; >> }; >> >> struct wl3501_join_confirm { >> diff --git a/drivers/net/wireless/wl3501_cs.c b/drivers/net/wireless/wl3501_cs.c >> index e149ef81d6cc..399d3bd2ae76 100644 >> --- a/drivers/net/wireless/wl3501_cs.c >> +++ b/drivers/net/wireless/wl3501_cs.c >> @@ -590,7 +590,7 @@ static int wl3501_mgmt_join(struct wl3501_card *this, u16 stas) >> struct wl3501_join_req sig = { >> .sig_id = WL3501_SIG_JOIN_REQ, >> .timeout = 10, >> - .ds_pset = { >> + .req.ds_pset = { >> .el = { >> .id = IW_MGMT_INFO_ELEMENT_DS_PARAMETER_SET, >> .len = 1, >> @@ -599,7 +599,7 @@ static int wl3501_mgmt_join(struct wl3501_card *this, u16 stas) >> }, >> }; >> >> - memcpy(&sig.beacon_period, &this->bss_set[stas].beacon_period, 72); >> + memcpy(&sig.req, &this->bss_set[stas].beacon_period, sizeof(sig.req)); > > If not, then probably something like this should be added to make sure > nothing unexpected happens to change structure sizes: > > BUILD_BUG_ON(sizeof(sig.req) != 72); Yep, this is sensible. Thanks for the feedback! -- Gustavo > >> return wl3501_esbq_exec(this, &sig, sizeof(sig)); >> } >> >> -- >> 2.27.0 >> >
diff --git a/drivers/net/wireless/wl3501.h b/drivers/net/wireless/wl3501.h index ef9d605d8c88..774d8cac046d 100644 --- a/drivers/net/wireless/wl3501.h +++ b/drivers/net/wireless/wl3501.h @@ -389,16 +389,18 @@ struct wl3501_join_req { u16 probe_delay; u8 timestamp[8]; u8 local_time[8]; - u16 beacon_period; - u16 dtim_period; - u16 cap_info; - u8 bss_type; - u8 bssid[ETH_ALEN]; - struct iw_mgmt_essid_pset ssid; - struct iw_mgmt_ds_pset ds_pset; - struct iw_mgmt_cf_pset cf_pset; - struct iw_mgmt_ibss_pset ibss_pset; - struct iw_mgmt_data_rset bss_basic_rset; + struct { + u16 beacon_period; + u16 dtim_period; + u16 cap_info; + u8 bss_type; + u8 bssid[ETH_ALEN]; + struct iw_mgmt_essid_pset ssid; + struct iw_mgmt_ds_pset ds_pset; + struct iw_mgmt_cf_pset cf_pset; + struct iw_mgmt_ibss_pset ibss_pset; + struct iw_mgmt_data_rset bss_basic_rset; + } req; }; struct wl3501_join_confirm { diff --git a/drivers/net/wireless/wl3501_cs.c b/drivers/net/wireless/wl3501_cs.c index e149ef81d6cc..399d3bd2ae76 100644 --- a/drivers/net/wireless/wl3501_cs.c +++ b/drivers/net/wireless/wl3501_cs.c @@ -590,7 +590,7 @@ static int wl3501_mgmt_join(struct wl3501_card *this, u16 stas) struct wl3501_join_req sig = { .sig_id = WL3501_SIG_JOIN_REQ, .timeout = 10, - .ds_pset = { + .req.ds_pset = { .el = { .id = IW_MGMT_INFO_ELEMENT_DS_PARAMETER_SET, .len = 1, @@ -599,7 +599,7 @@ static int wl3501_mgmt_join(struct wl3501_card *this, u16 stas) }, }; - memcpy(&sig.beacon_period, &this->bss_set[stas].beacon_period, 72); + memcpy(&sig.req, &this->bss_set[stas].beacon_period, sizeof(sig.req)); return wl3501_esbq_exec(this, &sig, sizeof(sig)); }
Fix the following out-of-bounds warning by enclosing some structure members into new struct req: arch/x86/include/asm/string_32.h:182:25: warning: '__builtin_memcpy' offset [39, 108] from the object at 'sig' is out of the bounds of referenced subobject 'beacon_period' with type 'short unsigned int' at offset 36 [-Warray-bounds] Refactor the code, accordingly: $ pahole -C wl3501_join_req drivers/net/wireless/wl3501_cs.o struct wl3501_join_req { u16 next_blk; /* 0 2 */ u8 sig_id; /* 2 1 */ u8 reserved; /* 3 1 */ struct iw_mgmt_data_rset operational_rset; /* 4 10 */ u16 reserved2; /* 14 2 */ u16 timeout; /* 16 2 */ u16 probe_delay; /* 18 2 */ u8 timestamp[8]; /* 20 8 */ u8 local_time[8]; /* 28 8 */ struct { u16 beacon_period; /* 36 2 */ u16 dtim_period; /* 38 2 */ u16 cap_info; /* 40 2 */ u8 bss_type; /* 42 1 */ u8 bssid[6]; /* 43 6 */ struct iw_mgmt_essid_pset ssid; /* 49 34 */ /* --- cacheline 1 boundary (64 bytes) was 19 bytes ago --- */ struct iw_mgmt_ds_pset ds_pset; /* 83 3 */ struct iw_mgmt_cf_pset cf_pset; /* 86 8 */ struct iw_mgmt_ibss_pset ibss_pset; /* 94 4 */ struct iw_mgmt_data_rset bss_basic_rset; /* 98 10 */ } req; /* 36 72 */ /* size: 108, cachelines: 2, members: 10 */ /* last cacheline: 44 bytes */ }; The problem is that the original code is trying to copy data into a bunch of struct members adjacent to each other in a single call to memcpy(). Now that a new struct _req_ enclosing all those adjacent members is introduced, memcpy() doesn't overrun the length of &sig.beacon_period, because the address of the new struct object _req_ is used as the destination, instead. Also, this helps with the ongoing efforts to enable -Warray-bounds and avoid confusing the compiler. Link: https://github.com/KSPP/linux/issues/109 Reported-by: kernel test robot <lkp@intel.com> Build-tested-by: kernel test robot <lkp@intel.com> Link: https://lore.kernel.org/lkml/60641d9b.2eNLedOGSdcSoAV2%25lkp@intel.com/ Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org> --- Changes in v2: - None. drivers/net/wireless/wl3501.h | 22 ++++++++++++---------- drivers/net/wireless/wl3501_cs.c | 4 ++-- 2 files changed, 14 insertions(+), 12 deletions(-)