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wl3501_cs: Fix out-of-bounds warnings in wl3501_mgmt_join
[ Upstream commit bb43e5718d8f1b46e7a77e7b39be3c691f293050 ] Fix the following out-of-bounds warnings by adding a new structure wl3501_req instead of duplicating the same members in structure wl3501_join_req and wl3501_scan_confirm: 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] arch/x86/include/asm/string_32.h:182:25: warning: '__builtin_memcpy' offset [25, 95] from the object at 'sig' is out of the bounds of referenced subobject 'beacon_period' with type 'short unsigned int' at offset 22 [-Warray-bounds] Refactor the code, accordingly: $ pahole -C wl3501_req drivers/net/wireless/wl3501_cs.o struct wl3501_req { u16 beacon_period; /* 0 2 */ u16 dtim_period; /* 2 2 */ u16 cap_info; /* 4 2 */ u8 bss_type; /* 6 1 */ u8 bssid[6]; /* 7 6 */ struct iw_mgmt_essid_pset ssid; /* 13 34 */ struct iw_mgmt_ds_pset ds_pset; /* 47 3 */ struct iw_mgmt_cf_pset cf_pset; /* 50 8 */ struct iw_mgmt_ibss_pset ibss_pset; /* 58 4 */ struct iw_mgmt_data_rset bss_basic_rset; /* 62 10 */ /* size: 72, cachelines: 2, members: 10 */ /* last cacheline: 8 bytes */ }; $ 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 wl3501_req req; /* 36 72 */ /* size: 108, cachelines: 2, members: 10 */ /* last cacheline: 44 bytes */ }; $ pahole -C wl3501_scan_confirm drivers/net/wireless/wl3501_cs.o struct wl3501_scan_confirm { u16 next_blk; /* 0 2 */ u8 sig_id; /* 2 1 */ u8 reserved; /* 3 1 */ u16 status; /* 4 2 */ char timestamp[8]; /* 6 8 */ char localtime[8]; /* 14 8 */ struct wl3501_req req; /* 22 72 */ /* --- cacheline 1 boundary (64 bytes) was 30 bytes ago --- */ u8 rssi; /* 94 1 */ /* size: 96, cachelines: 2, members: 8 */ /* padding: 1 */ /* last cacheline: 32 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 wl3501_req enclosing all those adjacent members is introduced, memcpy() doesn't overrun the length of &sig.beacon_period and &this->bss_set[i].beacon_period, because the address of the new struct object _req_ is used as the destination, instead. This helps with the ongoing efforts to globally enable -Warray-bounds and get us closer to being able to tighten the FORTIFY_SOURCE routines on memcpy(). Link: KSPP/linux#109 Reported-by: kernel test robot <[email protected]> Signed-off-by: Gustavo A. R. Silva <[email protected]> Reviewed-by: Kees Cook <[email protected]> Signed-off-by: Kalle Valo <[email protected]> Link: https://lore.kernel.org/r/1fbaf516da763b50edac47d792a9145aa4482e29.1618442265.git.gustavoars@kernel.org Signed-off-by: Sasha Levin <[email protected]>
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