On 2022-10-28 14:05, Kees Cook wrote: > GCC 12 appears to perform constant propagation incompletely(?) and can > no longer notice that "len" is always 0 when "data" is NULL. Expand the > check to avoid warnings about memcpy() having a NULL argument: > > ... > from drivers/crypto/caam/key_gen.c:8: > drivers/crypto/caam/desc_constr.h: In function 'append_data.constprop': > include/linux/fortify-string.h:48:33: warning: argument 2 null where non-null expected [-Wnonnull] > 48 | #define __underlying_memcpy __builtin_memcpy > | ^ > include/linux/fortify-string.h:438:9: note: in expansion of macro '__underlying_memcpy' > 438 | __underlying_##op(p, q, __fortify_size); \ > | ^~~~~~~~~~~~~ > > The NULL was being propagated from: > > append_fifo_load_as_imm(desc, NULL, 0, LDST_CLASS_2_CCB | > FIFOLD_TYPE_MSG | FIFOLD_TYPE_LAST2); > ... > static inline void append_##cmd##_as_imm(u32 * const desc, const void *data, \ > unsigned int len, u32 options) \ > { \ > PRINT_POS; \ > append_cmd_data(desc, data, len, CMD_##op | options); \ > } > ... > APPEND_CMD_PTR_TO_IMM(fifo_load, FIFO_LOAD); > ... > static inline void append_cmd_data(u32 * const desc, const void *data, int len, > u32 command) > { > append_cmd(desc, command | IMMEDIATE | len); > append_data(desc, data, len); > } > > Cc: "Horia Geantă" <horia.geanta@xxxxxxx> > Cc: Pankaj Gupta <pankaj.gupta@xxxxxxx> > Cc: Gaurav Jain <gaurav.jain@xxxxxxx> > Cc: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> > Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> > Cc: linux-crypto@xxxxxxxxxxxxxxx > Reported-by: kernel test robot <lkp@xxxxxxxxx> > Link: https://lore.kernel.org/lkml/202210290446.qBayTfzl-lkp@xxxxxxxxx > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> Tested-by: Anders Roxell <anders.roxell@xxxxxxxxxx> > --- > drivers/crypto/caam/desc_constr.h | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/crypto/caam/desc_constr.h b/drivers/crypto/caam/desc_constr.h > index 62ce6421bb3f..ddbba8b00ab7 100644 > --- a/drivers/crypto/caam/desc_constr.h > +++ b/drivers/crypto/caam/desc_constr.h > @@ -163,7 +163,7 @@ static inline void append_data(u32 * const desc, const void *data, int len) > { > u32 *offset = desc_end(desc); > > - if (len) /* avoid sparse warning: memcpy with byte count of 0 */ > + if (data && len) /* avoid sparse warning: memcpy with byte count of 0 */ Maybe we should update the comment, since newer releases of sparse doesn't warn about this. Cheers, Anders