Commit d9556011 authored by John Hubbard's avatar John Hubbard Committed by Greg Kroah-Hartman

x86/boot: Save fields explicitly, zero out everything else

commit a90118c4 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: default avatarThomas Gleixner <tglx@linutronix.de>
Suggested-by: default avatarH. Peter Anvin <hpa@zytor.com>
Signed-off-by: default avatarJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: default avatarThomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/20190731054627.5627-2-jhubbard@nvidia.comSigned-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent e063b03b
...@@ -18,6 +18,20 @@ ...@@ -18,6 +18,20 @@
* Note: efi_info is commonly left uninitialized, but that field has a * Note: efi_info is commonly left uninitialized, but that field has a
* private magic, so it is better to leave it unchanged. * 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) static void sanitize_boot_params(struct boot_params *boot_params)
{ {
/* /*
...@@ -36,19 +50,39 @@ static void sanitize_boot_params(struct boot_params *boot_params) ...@@ -36,19 +50,39 @@ static void sanitize_boot_params(struct boot_params *boot_params)
*/ */
if (boot_params->sentinel) { if (boot_params->sentinel) {
/* fields in boot_params are left uninitialized, clear them */ /* fields in boot_params are left uninitialized, clear them */
memset(&boot_params->ext_ramdisk_image, 0, static struct boot_params scratch;
(char *)&boot_params->efi_info - char *bp_base = (char *)boot_params;
(char *)&boot_params->ext_ramdisk_image); char *save_base = (char *)&scratch;
memset(&boot_params->kbd_status, 0, int i;
(char *)&boot_params->hdr -
(char *)&boot_params->kbd_status); const struct boot_params_to_save to_save[] = {
memset(&boot_params->_pad7[0], 0, BOOT_PARAM_PRESERVE(screen_info),
(char *)&boot_params->edd_mbr_sig_buffer[0] - BOOT_PARAM_PRESERVE(apm_bios_info),
(char *)&boot_params->_pad7[0]); BOOT_PARAM_PRESERVE(tboot_addr),
memset(&boot_params->_pad8[0], 0, BOOT_PARAM_PRESERVE(ist_info),
(char *)&boot_params->eddbuf[0] - BOOT_PARAM_PRESERVE(hd0_info),
(char *)&boot_params->_pad8[0]); BOOT_PARAM_PRESERVE(hd1_info),
memset(&boot_params->_pad9[0], 0, sizeof(boot_params->_pad9)); 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, to_save[i].len);
}
memcpy(boot_params, save_base, sizeof(*boot_params));
} }
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment