Using min_t(int, ...) as a potential array index implies to the compiler that negative offsets should be allowed. This is not the case, though. Replace min_t() with clamp_t(). Fixes the following warning exposed under future CONFIG_FORTIFY_SOURCE improvements: In file included from include/linux/string.h:253, from include/linux/bitmap.h:11, from include/linux/cpumask.h:12, from include/linux/smp.h:13, from include/linux/lockdep.h:14, from include/linux/rcupdate.h:29, from include/linux/rculist.h:11, from include/linux/pid.h:5, from include/linux/sched.h:14, from include/linux/delay.h:23, from drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:35: drivers/net/ethernet/chelsio/cxgb4/t4_hw.c: In function 't4_get_raw_vpd_params': include/linux/fortify-string.h:46:33: warning: '__builtin_memcpy' pointer overflow between offset 29 and size [2147483648, 4294967295] [-Warray-bounds] 46 | #define __underlying_memcpy __builtin_memcpy | ^ include/linux/fortify-string.h:388:9: note: in expansion of macro '__underlying_memcpy' 388 | __underlying_##op(p, q, __fortify_size); \ | ^~~~~~~~~~~~~ include/linux/fortify-string.h:433:26: note: in expansion of macro '__fortify_memcpy_chk' 433 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ | ^~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2796:9: note: in expansion of macro 'memcpy' 2796 | memcpy(p->id, vpd + id, min_t(int, id_len, ID_LEN)); | ^~~~~~ include/linux/fortify-string.h:46:33: warning: '__builtin_memcpy' pointer overflow between offset 0 and size [2147483648, 4294967295] [-Warray-bounds] 46 | #define __underlying_memcpy __builtin_memcpy | ^ include/linux/fortify-string.h:388:9: note: in expansion of macro '__underlying_memcpy' 388 | __underlying_##op(p, q, __fortify_size); \ | ^~~~~~~~~~~~~ include/linux/fortify-string.h:433:26: note: in expansion of macro '__fortify_memcpy_chk' 433 | #define memcpy(p, q, s) __fortify_memcpy_chk(p, q, s, \ | ^~~~~~~~~~~~~~~~~~~~ drivers/net/ethernet/chelsio/cxgb4/t4_hw.c:2798:9: note: in expansion of macro 'memcpy' 2798 | memcpy(p->sn, vpd + sn, min_t(int, sn_len, SERNUM_LEN)); | ^~~~~~ Additionally remove needless cast from u8[] to char * in last strim() call. Reported-by: kernel test robot <lkp@xxxxxxxxx> Link: https://lore.kernel.org/lkml/202205031926.FVP7epJM-lkp@xxxxxxxxx Fixes: fc9279298e3a ("cxgb4: Search VPD with pci_vpd_find_ro_info_keyword()") Fixes: 24c521f81c30 ("cxgb4: Use pci_vpd_find_id_string() to find VPD ID string") Cc: Raju Rangoju <rajur@xxxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Eric Dumazet <edumazet@xxxxxxxxxx> Cc: Jakub Kicinski <kuba@xxxxxxxxxx> Cc: Paolo Abeni <pabeni@xxxxxxxxxx> Cc: netdev@xxxxxxxxxxxxxxx Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> --- drivers/net/ethernet/chelsio/cxgb4/t4_hw.c | 10 +++++----- 1 file changed, 5 insertions(+), 5 deletions(-) diff --git a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c index e7b4e3ed056c..f119ec7323e5 100644 --- a/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c +++ b/drivers/net/ethernet/chelsio/cxgb4/t4_hw.c @@ -2793,14 +2793,14 @@ int t4_get_raw_vpd_params(struct adapter *adapter, struct vpd_params *p) goto out; na = ret; - memcpy(p->id, vpd + id, min_t(int, id_len, ID_LEN)); + memcpy(p->id, vpd + id, clamp_t(int, id_len, 0, ID_LEN)); strim(p->id); - memcpy(p->sn, vpd + sn, min_t(int, sn_len, SERNUM_LEN)); + memcpy(p->sn, vpd + sn, clamp_t(int, sn_len, 0, SERNUM_LEN)); strim(p->sn); - memcpy(p->pn, vpd + pn, min_t(int, pn_len, PN_LEN)); + memcpy(p->pn, vpd + pn, clamp_t(int, pn_len, 0, PN_LEN)); strim(p->pn); - memcpy(p->na, vpd + na, min_t(int, na_len, MACADDR_LEN)); - strim((char *)p->na); + memcpy(p->na, vpd + na, clamp_t(int, na_len, 0, MACADDR_LEN)); + strim(p->na); out: vfree(vpd); -- 2.32.0