Re: [linux-yocto] [PATCH] [for all x86 branches] x86/boot: Save fields explicitly, zero out everything else
Since this is destined for -stable, I'm not going to merge the individual patch.
I'm holding nearly all 5.2 updates until the last introduction issues
are fixed. By that time, I'll have the next round of -stable updates
ready to go as well.
Cheers,
Bruce
On Thu, Sep 5, 2019 at 6:02 AM wrote:
>
> From: John Hubbard
>
> commit a90118c445cc7f07781de26a9684d4ec58bfcfd1 upstream.
>
> Recent gcc compilers (gcc 9.1) generate warnings about an out of bounds
> memset, if the memset goes accross several fields of a struct. This
> generated a couple of warnings on x86_64 builds in sanitize_boot_params().
>
> Fix this by explicitly saving the fields in struct boot_params
> that are intended to be preserved, and zeroing all the rest.
>
> [ tglx: Tagged for stable as it breaks the warning free build there as well ]
>
> Suggested-by: Thomas Gleixner
> Suggested-by: H. Peter Anvin
> Signed-off-by: John Hubbard
> Signed-off-by: Thomas Gleixner
> Cc: sta...@vger.kernel.org
> Link: https://lkml.kernel.org/r/20190731054627.5627-2-jhubb...@nvidia.com
> Signed-off-by: Greg Kroah-Hartman
> ---
> Fix the following build warning. It has been merge to 5.2.11.
> Please consider merging if it's worth.
>
> ./arch/x86/include/asm/bootparam_utils.h:40:3: warning: ‘memset’ offset [197,
> 448] from the object at ‘boot_params’ is out of the bounds of referenced
> subobject ‘ext_ramdisk_image’ with type
> ‘unsigned int’ at offset 192 [-Warray-bounds]
>
> ./arch/x86/include/asm/bootparam_utils.h:43:3: warning: ‘memset’ offset [493,
> 497] from the object at ‘boot_params’ is out of the bounds of referenced
> subobject ‘kbd_status’ with type ‘unsig
> ned char’ at offset 491 [-Warray-bounds]
>
> arch/x86/include/asm/bootparam_utils.h | 63
> ++
> 1 file changed, 48 insertions(+), 15 deletions(-)
>
> diff --git a/arch/x86/include/asm/bootparam_utils.h
> b/arch/x86/include/asm/bootparam_utils.h
> index f6f6ef4..7fed0fc 100644
> --- a/arch/x86/include/asm/bootparam_utils.h
> +++ b/arch/x86/include/asm/bootparam_utils.h
> @@ -18,6 +18,20 @@
> * Note: efi_info is commonly left uninitialized, but that field has a
> * private magic, so it is better to leave it unchanged.
> */
> +
> +#define sizeof_mbr(type, member) ({ sizeof(((type *)0)->member); })
> +
> +#define BOOT_PARAM_PRESERVE(struct_member) \
> + { \
> + .start = offsetof(struct boot_params, struct_member), \
> + .len = sizeof_mbr(struct boot_params, struct_member), \
> + }
> +
> +struct boot_params_to_save {
> + unsigned int start;
> + unsigned int len;
> +};
> +
> static void sanitize_boot_params(struct boot_params *boot_params)
> {
> /*
> @@ -35,21 +49,40 @@ static void sanitize_boot_params(struct boot_params
> *boot_params)
> * problems again.
> */
> if (boot_params->sentinel) {
> - /* fields in boot_params are left uninitialized, clear them */
> - boot_params->acpi_rsdp_addr = 0;
> - memset(&boot_params->ext_ramdisk_image, 0,
> - (char *)&boot_params->efi_info -
> - (char *)&boot_params->ext_ramdisk_image);
> - memset(&boot_params->kbd_status, 0,
> - (char *)&boot_params->hdr -
> - (char *)&boot_params->kbd_status);
> - memset(&boot_params->_pad7[0], 0,
> - (char *)&boot_params->edd_mbr_sig_buffer[0] -
> - (char *)&boot_params->_pad7[0]);
> - memset(&boot_params->_pad8[0], 0,
> - (char *)&boot_params->eddbuf[0] -
> - (char *)&boot_params->_pad8[0]);
> - memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9));
> + static struct boot_params scratch;
> + char *bp_base = (char *)boot_params;
> + char *save_base = (char *)&scratch;
> + int i;
> +
> + const struct boot_params_to_save to_save[] = {
> + BOOT_PARAM_PRESERVE(screen_info),
> + BOOT_PARAM_PRESERVE(apm_bios_info),
> + BOOT_PARAM_PRESERVE(tboot_addr),
> + BOOT_PARAM_PRESERVE(ist_info),
> + BOOT_PARAM_PRESERVE(acpi_rsdp_addr),
> + BOOT_PARAM_PRESERVE(hd0_info),
> + BOOT_PARAM_PRESERVE(hd1_info),
> + BOOT_PARAM_PRESERVE(sys_desc_table),
> + BOOT_PARAM_PRESERVE(olpc_ofw_header),
> + BOOT_PARAM_PRESERVE(efi_info),
> + BOOT_PARAM_PRESERVE(alt_mem_k),
> + BOOT_PARAM_PRESERVE(scratch),
> + BOOT_PARAM_PRESERVE(e820_entries),
> + BOOT_PARAM_PRESERVE(eddbuf_entries),
>
[linux-yocto] [PATCH] [for all x86 branches] x86/boot: Save fields explicitly, zero out everything else
From: John Hubbard
commit a90118c445cc7f07781de26a9684d4ec58bfcfd1 upstream.
Recent gcc compilers (gcc 9.1) generate warnings about an out of bounds
memset, if the memset goes accross several fields of a struct. This
generated a couple of warnings on x86_64 builds in sanitize_boot_params().
Fix this by explicitly saving the fields in struct boot_params
that are intended to be preserved, and zeroing all the rest.
[ tglx: Tagged for stable as it breaks the warning free build there as well ]
Suggested-by: Thomas Gleixner
Suggested-by: H. Peter Anvin
Signed-off-by: John Hubbard
Signed-off-by: Thomas Gleixner
Cc: sta...@vger.kernel.org
Link: https://lkml.kernel.org/r/20190731054627.5627-2-jhubb...@nvidia.com
Signed-off-by: Greg Kroah-Hartman
---
Fix the following build warning. It has been merge to 5.2.11.
Please consider merging if it's worth.
./arch/x86/include/asm/bootparam_utils.h:40:3: warning: ‘memset’ offset [197,
448] from the object at ‘boot_params’ is out of the bounds of referenced
subobject ‘ext_ramdisk_image’ with type
‘unsigned int’ at offset 192 [-Warray-bounds]
./arch/x86/include/asm/bootparam_utils.h:43:3: warning: ‘memset’ offset [493,
497] from the object at ‘boot_params’ is out of the bounds of referenced
subobject ‘kbd_status’ with type ‘unsig
ned char’ at offset 491 [-Warray-bounds]
arch/x86/include/asm/bootparam_utils.h | 63 ++
1 file changed, 48 insertions(+), 15 deletions(-)
diff --git a/arch/x86/include/asm/bootparam_utils.h
b/arch/x86/include/asm/bootparam_utils.h
index f6f6ef4..7fed0fc 100644
--- a/arch/x86/include/asm/bootparam_utils.h
+++ b/arch/x86/include/asm/bootparam_utils.h
@@ -18,6 +18,20 @@
* Note: efi_info is commonly left uninitialized, but that field has a
* private magic, so it is better to leave it unchanged.
*/
+
+#define sizeof_mbr(type, member) ({ sizeof(((type *)0)->member); })
+
+#define BOOT_PARAM_PRESERVE(struct_member) \
+ { \
+ .start = offsetof(struct boot_params, struct_member), \
+ .len = sizeof_mbr(struct boot_params, struct_member), \
+ }
+
+struct boot_params_to_save {
+ unsigned int start;
+ unsigned int len;
+};
+
static void sanitize_boot_params(struct boot_params *boot_params)
{
/*
@@ -35,21 +49,40 @@ static void sanitize_boot_params(struct boot_params
*boot_params)
* problems again.
*/
if (boot_params->sentinel) {
- /* fields in boot_params are left uninitialized, clear them */
- boot_params->acpi_rsdp_addr = 0;
- memset(&boot_params->ext_ramdisk_image, 0,
- (char *)&boot_params->efi_info -
- (char *)&boot_params->ext_ramdisk_image);
- memset(&boot_params->kbd_status, 0,
- (char *)&boot_params->hdr -
- (char *)&boot_params->kbd_status);
- memset(&boot_params->_pad7[0], 0,
- (char *)&boot_params->edd_mbr_sig_buffer[0] -
- (char *)&boot_params->_pad7[0]);
- memset(&boot_params->_pad8[0], 0,
- (char *)&boot_params->eddbuf[0] -
- (char *)&boot_params->_pad8[0]);
- memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9));
+ static struct boot_params scratch;
+ char *bp_base = (char *)boot_params;
+ char *save_base = (char *)&scratch;
+ int i;
+
+ const struct boot_params_to_save to_save[] = {
+ BOOT_PARAM_PRESERVE(screen_info),
+ BOOT_PARAM_PRESERVE(apm_bios_info),
+ BOOT_PARAM_PRESERVE(tboot_addr),
+ BOOT_PARAM_PRESERVE(ist_info),
+ BOOT_PARAM_PRESERVE(acpi_rsdp_addr),
+ BOOT_PARAM_PRESERVE(hd0_info),
+ BOOT_PARAM_PRESERVE(hd1_info),
+ BOOT_PARAM_PRESERVE(sys_desc_table),
+ BOOT_PARAM_PRESERVE(olpc_ofw_header),
+ BOOT_PARAM_PRESERVE(efi_info),
+ BOOT_PARAM_PRESERVE(alt_mem_k),
+ BOOT_PARAM_PRESERVE(scratch),
+ BOOT_PARAM_PRESERVE(e820_entries),
+ BOOT_PARAM_PRESERVE(eddbuf_entries),
+ BOOT_PARAM_PRESERVE(edd_mbr_sig_buf_entries),
+ BOOT_PARAM_PRESERVE(edd_mbr_sig_buffer),
+ BOOT_PARAM_PRESERVE(e820_table),
+ BOOT_PARAM_PRESERVE(eddbuf),
+ };
+
+ memset(&scratch, 0, sizeof(scratch));
+
+ for (i = 0; i < ARRAY_SIZE(to_save); i++) {
+ memcpy(save_base + to_save[i].start,
+ bp_base + to_save[i].start,
