From 55022fdeace8e432f008787ce03703bdcc9c3ca9 Mon Sep 17 00:00:00 2001 From: Colin Ian King Date: Tue, 30 Mar 2021 12:12:38 +0100 Subject: [PATCH] nvmem: core: Fix unintentional sign extension issue The shifting of the u8 integer buf[3] by 24 bits to the left will be promoted to a 32 bit signed int and then sign-extended to a u64. In the event that the top bit of buf[3] is set then all then all the upper 32 bits of the u64 end up as also being set because of the sign-extension. Fix this by casting buf[i] to a u64 before the shift. Fixes: a28e824fb827 ("nvmem: core: Add functions to make number reading easy") Reviewed-by: Douglas Anderson Signed-off-by: Colin Ian King Signed-off-by: Srinivas Kandagatla Addresses-Coverity: ("Unintended sign extension") Link: https://lore.kernel.org/r/20210330111241.19401-8-srinivas.kandagatla@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/nvmem/core.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/nvmem/core.c +++ b/drivers/nvmem/core.c @@ -1700,7 +1700,7 @@ int nvmem_cell_read_variable_le_u64(stru /* Copy w/ implicit endian conversion */ *val = 0; for (i = 0; i < len; i++) - *val |= buf[i] << (8 * i); + *val |= (uint64_t)buf[i] << (8 * i); kfree(buf);