* [PATCH] x86/boot: Wrap literal addresses in absolute_pointer()
@ 2022-02-27 19:59 Kees Cook
2022-02-27 20:25 ` Guenter Roeck
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: Kees Cook @ 2022-02-27 19:59 UTC (permalink / raw)
To: Thomas Gleixner
Cc: Kees Cook, Guenter Roeck, x86, linux-kernel, linux-hardening
GCC 11 (incorrectly[1]) assumes that literal values cast to (void *)
should be treated like a NULL pointer with an offset, and raises
diagnostics when doing bounds checking under -Warray-bounds. GCC 12
got "smarter" about finding these:
In function 'rdfs8',
inlined from 'vga_recalc_vertical' at /srv/code/arch/x86/boot/video-mode.c:124:29,
inlined from 'set_mode' at /srv/code/arch/x86/boot/video-mode.c:163:3:
/srv/code/arch/x86/boot/boot.h:114:9: warning: array subscript 0 is outside array bounds of 'u8[0]' {aka 'unsigned char[]'} [-Warray-bounds]
114 | asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
| ^~~
This has been solved in other places[2] already by using the recently
added absolute_pointer() macro. Do the same here.
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
[2] https://lore.kernel.org/all/20210912160149.2227137-1-linux@roeck-us.net/
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: x86@kernel.org
Signed-off-by: Kees Cook <keescook@chromium.org>
---
arch/x86/boot/boot.h | 36 ++++++++++++++++++++++++------------
arch/x86/boot/main.c | 2 +-
2 files changed, 25 insertions(+), 13 deletions(-)
diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index 34c9dbb6a47d..686a9d75a0e4 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -110,66 +110,78 @@ typedef unsigned int addr_t;
static inline u8 rdfs8(addr_t addr)
{
+ u8 *ptr = (u8 *)absolute_pointer(addr);
u8 v;
- asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
+ asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*ptr));
return v;
}
static inline u16 rdfs16(addr_t addr)
{
+ u16 *ptr = (u16 *)absolute_pointer(addr);
u16 v;
- asm volatile("movw %%fs:%1,%0" : "=r" (v) : "m" (*(u16 *)addr));
+ asm volatile("movw %%fs:%1,%0" : "=r" (v) : "m" (*ptr));
return v;
}
static inline u32 rdfs32(addr_t addr)
{
+ u32 *ptr = (u32 *)absolute_pointer(addr);
u32 v;
- asm volatile("movl %%fs:%1,%0" : "=r" (v) : "m" (*(u32 *)addr));
+ asm volatile("movl %%fs:%1,%0" : "=r" (v) : "m" (*ptr));
return v;
}
static inline void wrfs8(u8 v, addr_t addr)
{
- asm volatile("movb %1,%%fs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
+ u8 *ptr = (u8 *)absolute_pointer(addr);
+ asm volatile("movb %1,%%fs:%0" : "+m" (*ptr) : "qi" (v));
}
static inline void wrfs16(u16 v, addr_t addr)
{
- asm volatile("movw %1,%%fs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
+ u16 *ptr = (u16 *)absolute_pointer(addr);
+ asm volatile("movw %1,%%fs:%0" : "+m" (*ptr) : "ri" (v));
}
static inline void wrfs32(u32 v, addr_t addr)
{
- asm volatile("movl %1,%%fs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
+ u32 *ptr = (u32 *)absolute_pointer(addr);
+ asm volatile("movl %1,%%fs:%0" : "+m" (*ptr) : "ri" (v));
}
static inline u8 rdgs8(addr_t addr)
{
+ u8 *ptr = (u8 *)absolute_pointer(addr);
u8 v;
- asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
+ asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*ptr));
return v;
}
static inline u16 rdgs16(addr_t addr)
{
+ u16 *ptr = (u16 *)absolute_pointer(addr);
u16 v;
- asm volatile("movw %%gs:%1,%0" : "=r" (v) : "m" (*(u16 *)addr));
+ asm volatile("movw %%gs:%1,%0" : "=r" (v) : "m" (*ptr));
return v;
}
static inline u32 rdgs32(addr_t addr)
{
+ u32 *ptr = (u32 *)absolute_pointer(addr);
u32 v;
- asm volatile("movl %%gs:%1,%0" : "=r" (v) : "m" (*(u32 *)addr));
+ asm volatile("movl %%gs:%1,%0" : "=r" (v) : "m" (*ptr));
return v;
}
static inline void wrgs8(u8 v, addr_t addr)
{
- asm volatile("movb %1,%%gs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
+ u8 *ptr = (u8 *)absolute_pointer(addr);
+ asm volatile("movb %1,%%gs:%0" : "+m" (*ptr) : "qi" (v));
}
static inline void wrgs16(u16 v, addr_t addr)
{
- asm volatile("movw %1,%%gs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
+ u16 *ptr = (u16 *)absolute_pointer(addr);
+ asm volatile("movw %1,%%gs:%0" : "+m" (*ptr) : "ri" (v));
}
static inline void wrgs32(u32 v, addr_t addr)
{
- asm volatile("movl %1,%%gs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
+ u32 *ptr = (u32 *)absolute_pointer(addr);
+ asm volatile("movl %1,%%gs:%0" : "+m" (*ptr) : "ri" (v));
}
/* Note: these only return true/false, not a signed return value! */
diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c
index e3add857c2c9..c421af5a3cdc 100644
--- a/arch/x86/boot/main.c
+++ b/arch/x86/boot/main.c
@@ -33,7 +33,7 @@ static void copy_boot_params(void)
u16 cl_offset;
};
const struct old_cmdline * const oldcmd =
- (const struct old_cmdline *)OLD_CL_ADDRESS;
+ absolute_pointer(OLD_CL_ADDRESS);
BUILD_BUG_ON(sizeof(boot_params) != 4096);
memcpy(&boot_params.hdr, &hdr, sizeof(hdr));
--
2.32.0
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/boot: Wrap literal addresses in absolute_pointer()
2022-02-27 19:59 [PATCH] x86/boot: Wrap literal addresses in absolute_pointer() Kees Cook
@ 2022-02-27 20:25 ` Guenter Roeck
2022-05-19 5:41 ` Kees Cook
2022-05-19 10:57 ` [tip: x86/build] " tip-bot2 for Kees Cook
2 siblings, 0 replies; 4+ messages in thread
From: Guenter Roeck @ 2022-02-27 20:25 UTC (permalink / raw)
To: Kees Cook, Thomas Gleixner; +Cc: x86, linux-kernel, linux-hardening
On 2/27/22 11:59, Kees Cook wrote:
> GCC 11 (incorrectly[1]) assumes that literal values cast to (void *)
> should be treated like a NULL pointer with an offset, and raises
> diagnostics when doing bounds checking under -Warray-bounds. GCC 12
> got "smarter" about finding these:
>
> In function 'rdfs8',
> inlined from 'vga_recalc_vertical' at /srv/code/arch/x86/boot/video-mode.c:124:29,
> inlined from 'set_mode' at /srv/code/arch/x86/boot/video-mode.c:163:3:
> /srv/code/arch/x86/boot/boot.h:114:9: warning: array subscript 0 is outside array bounds of 'u8[0]' {aka 'unsigned char[]'} [-Warray-bounds]
> 114 | asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
> | ^~~
>
> This has been solved in other places[2] already by using the recently
> added absolute_pointer() macro. Do the same here.
>
> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
> [2] https://lore.kernel.org/all/20210912160149.2227137-1-linux@roeck-us.net/
>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: x86@kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> ---
> arch/x86/boot/boot.h | 36 ++++++++++++++++++++++++------------
> arch/x86/boot/main.c | 2 +-
> 2 files changed, 25 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
> index 34c9dbb6a47d..686a9d75a0e4 100644
> --- a/arch/x86/boot/boot.h
> +++ b/arch/x86/boot/boot.h
> @@ -110,66 +110,78 @@ typedef unsigned int addr_t;
>
> static inline u8 rdfs8(addr_t addr)
> {
> + u8 *ptr = (u8 *)absolute_pointer(addr);
> u8 v;
> - asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
> + asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*ptr));
> return v;
> }
> static inline u16 rdfs16(addr_t addr)
> {
> + u16 *ptr = (u16 *)absolute_pointer(addr);
> u16 v;
> - asm volatile("movw %%fs:%1,%0" : "=r" (v) : "m" (*(u16 *)addr));
> + asm volatile("movw %%fs:%1,%0" : "=r" (v) : "m" (*ptr));
> return v;
> }
> static inline u32 rdfs32(addr_t addr)
> {
> + u32 *ptr = (u32 *)absolute_pointer(addr);
> u32 v;
> - asm volatile("movl %%fs:%1,%0" : "=r" (v) : "m" (*(u32 *)addr));
> + asm volatile("movl %%fs:%1,%0" : "=r" (v) : "m" (*ptr));
> return v;
> }
>
> static inline void wrfs8(u8 v, addr_t addr)
> {
> - asm volatile("movb %1,%%fs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
> + u8 *ptr = (u8 *)absolute_pointer(addr);
> + asm volatile("movb %1,%%fs:%0" : "+m" (*ptr) : "qi" (v));
> }
> static inline void wrfs16(u16 v, addr_t addr)
> {
> - asm volatile("movw %1,%%fs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
> + u16 *ptr = (u16 *)absolute_pointer(addr);
> + asm volatile("movw %1,%%fs:%0" : "+m" (*ptr) : "ri" (v));
> }
> static inline void wrfs32(u32 v, addr_t addr)
> {
> - asm volatile("movl %1,%%fs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
> + u32 *ptr = (u32 *)absolute_pointer(addr);
> + asm volatile("movl %1,%%fs:%0" : "+m" (*ptr) : "ri" (v));
> }
>
> static inline u8 rdgs8(addr_t addr)
> {
> + u8 *ptr = (u8 *)absolute_pointer(addr);
> u8 v;
> - asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
> + asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*ptr));
> return v;
> }
> static inline u16 rdgs16(addr_t addr)
> {
> + u16 *ptr = (u16 *)absolute_pointer(addr);
> u16 v;
> - asm volatile("movw %%gs:%1,%0" : "=r" (v) : "m" (*(u16 *)addr));
> + asm volatile("movw %%gs:%1,%0" : "=r" (v) : "m" (*ptr));
> return v;
> }
> static inline u32 rdgs32(addr_t addr)
> {
> + u32 *ptr = (u32 *)absolute_pointer(addr);
> u32 v;
> - asm volatile("movl %%gs:%1,%0" : "=r" (v) : "m" (*(u32 *)addr));
> + asm volatile("movl %%gs:%1,%0" : "=r" (v) : "m" (*ptr));
> return v;
> }
>
> static inline void wrgs8(u8 v, addr_t addr)
> {
> - asm volatile("movb %1,%%gs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
> + u8 *ptr = (u8 *)absolute_pointer(addr);
> + asm volatile("movb %1,%%gs:%0" : "+m" (*ptr) : "qi" (v));
> }
> static inline void wrgs16(u16 v, addr_t addr)
> {
> - asm volatile("movw %1,%%gs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
> + u16 *ptr = (u16 *)absolute_pointer(addr);
> + asm volatile("movw %1,%%gs:%0" : "+m" (*ptr) : "ri" (v));
> }
> static inline void wrgs32(u32 v, addr_t addr)
> {
> - asm volatile("movl %1,%%gs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
> + u32 *ptr = (u32 *)absolute_pointer(addr);
> + asm volatile("movl %1,%%gs:%0" : "+m" (*ptr) : "ri" (v));
> }
>
> /* Note: these only return true/false, not a signed return value! */
> diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c
> index e3add857c2c9..c421af5a3cdc 100644
> --- a/arch/x86/boot/main.c
> +++ b/arch/x86/boot/main.c
> @@ -33,7 +33,7 @@ static void copy_boot_params(void)
> u16 cl_offset;
> };
> const struct old_cmdline * const oldcmd =
> - (const struct old_cmdline *)OLD_CL_ADDRESS;
> + absolute_pointer(OLD_CL_ADDRESS);
>
> BUILD_BUG_ON(sizeof(boot_params) != 4096);
> memcpy(&boot_params.hdr, &hdr, sizeof(hdr));
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] x86/boot: Wrap literal addresses in absolute_pointer()
2022-02-27 19:59 [PATCH] x86/boot: Wrap literal addresses in absolute_pointer() Kees Cook
2022-02-27 20:25 ` Guenter Roeck
@ 2022-05-19 5:41 ` Kees Cook
2022-05-19 10:57 ` [tip: x86/build] " tip-bot2 for Kees Cook
2 siblings, 0 replies; 4+ messages in thread
From: Kees Cook @ 2022-05-19 5:41 UTC (permalink / raw)
To: Thomas Gleixner; +Cc: Guenter Roeck, x86, linux-kernel, linux-hardening
On Sun, Feb 27, 2022 at 11:59:18AM -0800, Kees Cook wrote:
> GCC 11 (incorrectly[1]) assumes that literal values cast to (void *)
> should be treated like a NULL pointer with an offset, and raises
> diagnostics when doing bounds checking under -Warray-bounds. GCC 12
> got "smarter" about finding these:
>
> In function 'rdfs8',
> inlined from 'vga_recalc_vertical' at /srv/code/arch/x86/boot/video-mode.c:124:29,
> inlined from 'set_mode' at /srv/code/arch/x86/boot/video-mode.c:163:3:
> /srv/code/arch/x86/boot/boot.h:114:9: warning: array subscript 0 is outside array bounds of 'u8[0]' {aka 'unsigned char[]'} [-Warray-bounds]
> 114 | asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
> | ^~~
>
> This has been solved in other places[2] already by using the recently
> added absolute_pointer() macro. Do the same here.
>
> [1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
> [2] https://lore.kernel.org/all/20210912160149.2227137-1-linux@roeck-us.net/
>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: x86@kernel.org
> Signed-off-by: Kees Cook <keescook@chromium.org>
Thread ping -- this is still needed for GCC 12. Can an x86 maintainer
either take this or Ack it and I'll carry it?
Thanks!
-Kees
> ---
> arch/x86/boot/boot.h | 36 ++++++++++++++++++++++++------------
> arch/x86/boot/main.c | 2 +-
> 2 files changed, 25 insertions(+), 13 deletions(-)
>
> diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
> index 34c9dbb6a47d..686a9d75a0e4 100644
> --- a/arch/x86/boot/boot.h
> +++ b/arch/x86/boot/boot.h
> @@ -110,66 +110,78 @@ typedef unsigned int addr_t;
>
> static inline u8 rdfs8(addr_t addr)
> {
> + u8 *ptr = (u8 *)absolute_pointer(addr);
> u8 v;
> - asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
> + asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*ptr));
> return v;
> }
> static inline u16 rdfs16(addr_t addr)
> {
> + u16 *ptr = (u16 *)absolute_pointer(addr);
> u16 v;
> - asm volatile("movw %%fs:%1,%0" : "=r" (v) : "m" (*(u16 *)addr));
> + asm volatile("movw %%fs:%1,%0" : "=r" (v) : "m" (*ptr));
> return v;
> }
> static inline u32 rdfs32(addr_t addr)
> {
> + u32 *ptr = (u32 *)absolute_pointer(addr);
> u32 v;
> - asm volatile("movl %%fs:%1,%0" : "=r" (v) : "m" (*(u32 *)addr));
> + asm volatile("movl %%fs:%1,%0" : "=r" (v) : "m" (*ptr));
> return v;
> }
>
> static inline void wrfs8(u8 v, addr_t addr)
> {
> - asm volatile("movb %1,%%fs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
> + u8 *ptr = (u8 *)absolute_pointer(addr);
> + asm volatile("movb %1,%%fs:%0" : "+m" (*ptr) : "qi" (v));
> }
> static inline void wrfs16(u16 v, addr_t addr)
> {
> - asm volatile("movw %1,%%fs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
> + u16 *ptr = (u16 *)absolute_pointer(addr);
> + asm volatile("movw %1,%%fs:%0" : "+m" (*ptr) : "ri" (v));
> }
> static inline void wrfs32(u32 v, addr_t addr)
> {
> - asm volatile("movl %1,%%fs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
> + u32 *ptr = (u32 *)absolute_pointer(addr);
> + asm volatile("movl %1,%%fs:%0" : "+m" (*ptr) : "ri" (v));
> }
>
> static inline u8 rdgs8(addr_t addr)
> {
> + u8 *ptr = (u8 *)absolute_pointer(addr);
> u8 v;
> - asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
> + asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*ptr));
> return v;
> }
> static inline u16 rdgs16(addr_t addr)
> {
> + u16 *ptr = (u16 *)absolute_pointer(addr);
> u16 v;
> - asm volatile("movw %%gs:%1,%0" : "=r" (v) : "m" (*(u16 *)addr));
> + asm volatile("movw %%gs:%1,%0" : "=r" (v) : "m" (*ptr));
> return v;
> }
> static inline u32 rdgs32(addr_t addr)
> {
> + u32 *ptr = (u32 *)absolute_pointer(addr);
> u32 v;
> - asm volatile("movl %%gs:%1,%0" : "=r" (v) : "m" (*(u32 *)addr));
> + asm volatile("movl %%gs:%1,%0" : "=r" (v) : "m" (*ptr));
> return v;
> }
>
> static inline void wrgs8(u8 v, addr_t addr)
> {
> - asm volatile("movb %1,%%gs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
> + u8 *ptr = (u8 *)absolute_pointer(addr);
> + asm volatile("movb %1,%%gs:%0" : "+m" (*ptr) : "qi" (v));
> }
> static inline void wrgs16(u16 v, addr_t addr)
> {
> - asm volatile("movw %1,%%gs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
> + u16 *ptr = (u16 *)absolute_pointer(addr);
> + asm volatile("movw %1,%%gs:%0" : "+m" (*ptr) : "ri" (v));
> }
> static inline void wrgs32(u32 v, addr_t addr)
> {
> - asm volatile("movl %1,%%gs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
> + u32 *ptr = (u32 *)absolute_pointer(addr);
> + asm volatile("movl %1,%%gs:%0" : "+m" (*ptr) : "ri" (v));
> }
>
> /* Note: these only return true/false, not a signed return value! */
> diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c
> index e3add857c2c9..c421af5a3cdc 100644
> --- a/arch/x86/boot/main.c
> +++ b/arch/x86/boot/main.c
> @@ -33,7 +33,7 @@ static void copy_boot_params(void)
> u16 cl_offset;
> };
> const struct old_cmdline * const oldcmd =
> - (const struct old_cmdline *)OLD_CL_ADDRESS;
> + absolute_pointer(OLD_CL_ADDRESS);
>
> BUILD_BUG_ON(sizeof(boot_params) != 4096);
> memcpy(&boot_params.hdr, &hdr, sizeof(hdr));
> --
> 2.32.0
>
--
Kees Cook
^ permalink raw reply [flat|nested] 4+ messages in thread
* [tip: x86/build] x86/boot: Wrap literal addresses in absolute_pointer()
2022-02-27 19:59 [PATCH] x86/boot: Wrap literal addresses in absolute_pointer() Kees Cook
2022-02-27 20:25 ` Guenter Roeck
2022-05-19 5:41 ` Kees Cook
@ 2022-05-19 10:57 ` tip-bot2 for Kees Cook
2 siblings, 0 replies; 4+ messages in thread
From: tip-bot2 for Kees Cook @ 2022-05-19 10:57 UTC (permalink / raw)
To: linux-tip-commits
Cc: Kees Cook, Borislav Petkov, Guenter Roeck, x86, linux-kernel
The following commit has been merged into the x86/build branch of tip:
Commit-ID: aeb84412037b89e06f45e382f044da6f200e12f8
Gitweb: https://git.kernel.org/tip/aeb84412037b89e06f45e382f044da6f200e12f8
Author: Kees Cook <keescook@chromium.org>
AuthorDate: Sun, 27 Feb 2022 11:59:18 -08:00
Committer: Borislav Petkov <bp@suse.de>
CommitterDate: Thu, 19 May 2022 12:47:30 +02:00
x86/boot: Wrap literal addresses in absolute_pointer()
GCC 11 (incorrectly[1]) assumes that literal values cast to (void *)
should be treated like a NULL pointer with an offset, and raises
diagnostics when doing bounds checking under -Warray-bounds. GCC 12
got "smarter" about finding these:
In function 'rdfs8',
inlined from 'vga_recalc_vertical' at /srv/code/arch/x86/boot/video-mode.c:124:29,
inlined from 'set_mode' at /srv/code/arch/x86/boot/video-mode.c:163:3:
/srv/code/arch/x86/boot/boot.h:114:9: warning: array subscript 0 is outside array bounds of 'u8[0]' {aka 'unsigned char[]'} [-Warray-bounds]
114 | asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
| ^~~
This has been solved in other places[2] already by using the recently
added absolute_pointer() macro. Do the same here.
[1] https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99578
[2] https://lore.kernel.org/all/20210912160149.2227137-1-linux@roeck-us.net/
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220227195918.705219-1-keescook@chromium.org
---
arch/x86/boot/boot.h | 36 ++++++++++++++++++++++++------------
arch/x86/boot/main.c | 2 +-
2 files changed, 25 insertions(+), 13 deletions(-)
diff --git a/arch/x86/boot/boot.h b/arch/x86/boot/boot.h
index 34c9dbb..686a9d7 100644
--- a/arch/x86/boot/boot.h
+++ b/arch/x86/boot/boot.h
@@ -110,66 +110,78 @@ typedef unsigned int addr_t;
static inline u8 rdfs8(addr_t addr)
{
+ u8 *ptr = (u8 *)absolute_pointer(addr);
u8 v;
- asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
+ asm volatile("movb %%fs:%1,%0" : "=q" (v) : "m" (*ptr));
return v;
}
static inline u16 rdfs16(addr_t addr)
{
+ u16 *ptr = (u16 *)absolute_pointer(addr);
u16 v;
- asm volatile("movw %%fs:%1,%0" : "=r" (v) : "m" (*(u16 *)addr));
+ asm volatile("movw %%fs:%1,%0" : "=r" (v) : "m" (*ptr));
return v;
}
static inline u32 rdfs32(addr_t addr)
{
+ u32 *ptr = (u32 *)absolute_pointer(addr);
u32 v;
- asm volatile("movl %%fs:%1,%0" : "=r" (v) : "m" (*(u32 *)addr));
+ asm volatile("movl %%fs:%1,%0" : "=r" (v) : "m" (*ptr));
return v;
}
static inline void wrfs8(u8 v, addr_t addr)
{
- asm volatile("movb %1,%%fs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
+ u8 *ptr = (u8 *)absolute_pointer(addr);
+ asm volatile("movb %1,%%fs:%0" : "+m" (*ptr) : "qi" (v));
}
static inline void wrfs16(u16 v, addr_t addr)
{
- asm volatile("movw %1,%%fs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
+ u16 *ptr = (u16 *)absolute_pointer(addr);
+ asm volatile("movw %1,%%fs:%0" : "+m" (*ptr) : "ri" (v));
}
static inline void wrfs32(u32 v, addr_t addr)
{
- asm volatile("movl %1,%%fs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
+ u32 *ptr = (u32 *)absolute_pointer(addr);
+ asm volatile("movl %1,%%fs:%0" : "+m" (*ptr) : "ri" (v));
}
static inline u8 rdgs8(addr_t addr)
{
+ u8 *ptr = (u8 *)absolute_pointer(addr);
u8 v;
- asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*(u8 *)addr));
+ asm volatile("movb %%gs:%1,%0" : "=q" (v) : "m" (*ptr));
return v;
}
static inline u16 rdgs16(addr_t addr)
{
+ u16 *ptr = (u16 *)absolute_pointer(addr);
u16 v;
- asm volatile("movw %%gs:%1,%0" : "=r" (v) : "m" (*(u16 *)addr));
+ asm volatile("movw %%gs:%1,%0" : "=r" (v) : "m" (*ptr));
return v;
}
static inline u32 rdgs32(addr_t addr)
{
+ u32 *ptr = (u32 *)absolute_pointer(addr);
u32 v;
- asm volatile("movl %%gs:%1,%0" : "=r" (v) : "m" (*(u32 *)addr));
+ asm volatile("movl %%gs:%1,%0" : "=r" (v) : "m" (*ptr));
return v;
}
static inline void wrgs8(u8 v, addr_t addr)
{
- asm volatile("movb %1,%%gs:%0" : "+m" (*(u8 *)addr) : "qi" (v));
+ u8 *ptr = (u8 *)absolute_pointer(addr);
+ asm volatile("movb %1,%%gs:%0" : "+m" (*ptr) : "qi" (v));
}
static inline void wrgs16(u16 v, addr_t addr)
{
- asm volatile("movw %1,%%gs:%0" : "+m" (*(u16 *)addr) : "ri" (v));
+ u16 *ptr = (u16 *)absolute_pointer(addr);
+ asm volatile("movw %1,%%gs:%0" : "+m" (*ptr) : "ri" (v));
}
static inline void wrgs32(u32 v, addr_t addr)
{
- asm volatile("movl %1,%%gs:%0" : "+m" (*(u32 *)addr) : "ri" (v));
+ u32 *ptr = (u32 *)absolute_pointer(addr);
+ asm volatile("movl %1,%%gs:%0" : "+m" (*ptr) : "ri" (v));
}
/* Note: these only return true/false, not a signed return value! */
diff --git a/arch/x86/boot/main.c b/arch/x86/boot/main.c
index e3add85..c421af5 100644
--- a/arch/x86/boot/main.c
+++ b/arch/x86/boot/main.c
@@ -33,7 +33,7 @@ static void copy_boot_params(void)
u16 cl_offset;
};
const struct old_cmdline * const oldcmd =
- (const struct old_cmdline *)OLD_CL_ADDRESS;
+ absolute_pointer(OLD_CL_ADDRESS);
BUILD_BUG_ON(sizeof(boot_params) != 4096);
memcpy(&boot_params.hdr, &hdr, sizeof(hdr));
^ permalink raw reply related [flat|nested] 4+ messages in thread
end of thread, other threads:[~2022-05-19 10:58 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2022-02-27 19:59 [PATCH] x86/boot: Wrap literal addresses in absolute_pointer() Kees Cook
2022-02-27 20:25 ` Guenter Roeck
2022-05-19 5:41 ` Kees Cook
2022-05-19 10:57 ` [tip: x86/build] " tip-bot2 for Kees Cook
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