[PATCH 3/4] common: bootm: add checks to verify if ramdisk / fdtimage overlaps OS image

Jaehoon Chung jh80.chung at samsung.com
Tue Oct 20 13:07:04 CEST 2020


Dear Tero,

On 6/12/20 9:41 PM, Tero Kristo wrote:
> These cases are typically fatal and are difficult to debug for random
> users. Add checks for detecting overlapping images and abort if overlap
> is detected.

I have a question about your patch.. because I have confused...
So i want to clear what i missed.


During booting with ramdisk, my target is stopped.

ramdisk start address = 0x2700000
size = 0x800000
kernel start - 0x2F00000

bootm 0x2f00000 0x2700000:0x800000 0x02600000


ramdisk.end is ramdisk_start + size (0x2F00000) 

Then it will be used until 0x2efffff, not 0x2f00000.
When i have checked, it doesn't overwrite RD image.

> +	/* check if ramdisk overlaps OS image */
> +	if (images.rd_start && (((ulong)images.rd_start >= start &&
> +				 (ulong)images.rd_start <= start + size) ||
> +				((ulong)images.rd_end >= start &&
> +				 (ulong)images.rd_end <= start + size))) {
> +		printf("ERROR: RD image overlaps OS image (OS=0x%lx..0x%lx)\n",
> +		       start, start + size);> +		return 1;
> +	}

Because of hit this condition...So doesn't boot...

I think that it needs to change the below conditions..

images.rd_start < start + size or images.rd_start < start + size - 1.
images.rd_end > start or image.rd_end - 1 >= start 

If i misunderstood something, let me know, plz.

Best Regards,
Jaehoon Chung

> 
> Signed-off-by: Tero Kristo <t-kristo at ti.com>
> ---
>  cmd/booti.c       |  2 +-
>  cmd/bootz.c       |  2 +-
>  common/bootm.c    | 29 +++++++++++++++++++++++++++--
>  common/bootm_os.c |  4 ++--
>  include/bootm.h   |  3 ++-
>  5 files changed, 33 insertions(+), 7 deletions(-)
> 
> diff --git a/cmd/booti.c b/cmd/booti.c
> index ae37975494..6153b229cf 100644
> --- a/cmd/booti.c
> +++ b/cmd/booti.c
> @@ -93,7 +93,7 @@ static int booti_start(struct cmd_tbl *cmdtp, int flag, int argc,
>  	 * Handle the BOOTM_STATE_FINDOTHER state ourselves as we do not
>  	 * have a header that provide this informaiton.
>  	 */
> -	if (bootm_find_images(flag, argc, argv))
> +	if (bootm_find_images(flag, argc, argv, relocated_addr, image_size))
>  		return 1;
>  
>  	return 0;
> diff --git a/cmd/bootz.c b/cmd/bootz.c
> index bc15fd8ec4..1c8b0cf89f 100644
> --- a/cmd/bootz.c
> +++ b/cmd/bootz.c
> @@ -54,7 +54,7 @@ static int bootz_start(struct cmd_tbl *cmdtp, int flag, int argc,
>  	 * Handle the BOOTM_STATE_FINDOTHER state ourselves as we do not
>  	 * have a header that provide this informaiton.
>  	 */
> -	if (bootm_find_images(flag, argc, argv))
> +	if (bootm_find_images(flag, argc, argv, zi_start, zi_end - zi_start))
>  		return 1;
>  
>  	return 0;
> diff --git a/common/bootm.c b/common/bootm.c
> index 2ed7521520..247b600d9c 100644
> --- a/common/bootm.c
> +++ b/common/bootm.c
> @@ -228,6 +228,8 @@ static int bootm_find_os(struct cmd_tbl *cmdtp, int flag, int argc,
>   * @flag: Ignored Argument
>   * @argc: command argument count
>   * @argv: command argument list
> + * @start: OS image start address
> + * @size: OS image size
>   *
>   * boot_find_images() will attempt to load an available ramdisk,
>   * flattened device tree, as well as specifically marked
> @@ -239,7 +241,8 @@ static int bootm_find_os(struct cmd_tbl *cmdtp, int flag, int argc,
>   *     0, if all existing images were loaded correctly
>   *     1, if an image is found but corrupted, or invalid
>   */
> -int bootm_find_images(int flag, int argc, char *const argv[])
> +int bootm_find_images(int flag, int argc, char *const argv[], ulong start,
> +		      ulong size)
>  {
>  	int ret;
>  
> @@ -251,6 +254,16 @@ int bootm_find_images(int flag, int argc, char *const argv[])
>  		return 1;
>  	}
>  
> +	/* check if ramdisk overlaps OS image */
> +	if (images.rd_start && (((ulong)images.rd_start >= start &&
> +				 (ulong)images.rd_start <= start + size) ||
> +				((ulong)images.rd_end >= start &&
> +				 (ulong)images.rd_end <= start + size))) {
> +		printf("ERROR: RD image overlaps OS image (OS=0x%lx..0x%lx)\n",
> +		       start, start + size);
> +		return 1;
> +	}
> +
>  #if IMAGE_ENABLE_OF_LIBFDT
>  	/* find flattened device tree */
>  	ret = boot_get_fdt(flag, argc, argv, IH_ARCH_DEFAULT, &images,
> @@ -259,6 +272,18 @@ int bootm_find_images(int flag, int argc, char *const argv[])
>  		puts("Could not find a valid device tree\n");
>  		return 1;
>  	}
> +
> +	/* check if FDT overlaps OS image */
> +	if (images.ft_addr &&
> +	    (((ulong)images.ft_addr >= start &&
> +	      (ulong)images.ft_addr <= start + size) ||
> +	     ((ulong)images.ft_addr + images.ft_len >= start &&
> +	      (ulong)images.ft_addr + images.ft_len <= start + size))) {
> +		printf("ERROR: FDT image overlaps OS image (OS=0x%lx..0x%lx)\n",
> +		       start, start + size);
> +		return 1;
> +	}
> +
>  	if (CONFIG_IS_ENABLED(CMD_FDT))
>  		set_working_fdt_addr(map_to_sysmem(images.ft_addr));
>  #endif
> @@ -294,7 +319,7 @@ static int bootm_find_other(struct cmd_tbl *cmdtp, int flag, int argc,
>  	     (images.os.type == IH_TYPE_MULTI)) &&
>  	    (images.os.os == IH_OS_LINUX ||
>  		 images.os.os == IH_OS_VXWORKS))
> -		return bootm_find_images(flag, argc, argv);
> +		return bootm_find_images(flag, argc, argv, 0, 0);
>  
>  	return 0;
>  }
> diff --git a/common/bootm_os.c b/common/bootm_os.c
> index 55296483f7..a3c360e80a 100644
> --- a/common/bootm_os.c
> +++ b/common/bootm_os.c
> @@ -495,7 +495,7 @@ static int do_bootm_tee(int flag, int argc, char *const argv[],
>  		return ret;
>  
>  	/* Locate FDT etc */
> -	ret = bootm_find_images(flag, argc, argv);
> +	ret = bootm_find_images(flag, argc, argv, 0, 0);
>  	if (ret)
>  		return ret;
>  
> @@ -516,7 +516,7 @@ static int do_bootm_efi(int flag, int argc, char *const argv[],
>  		return 0;
>  
>  	/* Locate FDT, if provided */
> -	ret = bootm_find_images(flag, argc, argv);
> +	ret = bootm_find_images(flag, argc, argv, 0, 0);
>  	if (ret)
>  		return ret;
>  
> diff --git a/include/bootm.h b/include/bootm.h
> index 1e7f29e134..0350c349f3 100644
> --- a/include/bootm.h
> +++ b/include/bootm.h
> @@ -53,7 +53,8 @@ int boot_selected_os(int argc, char *const argv[], int state,
>  ulong bootm_disable_interrupts(void);
>  
>  /* This is a special function used by booti/bootz */
> -int bootm_find_images(int flag, int argc, char *const argv[]);
> +int bootm_find_images(int flag, int argc, char *const argv[], ulong start,
> +		      ulong size);
>  
>  int do_bootm_states(struct cmd_tbl *cmdtp, int flag, int argc,
>  		    char *const argv[], int states, bootm_headers_t *images,
> 



More information about the U-Boot mailing list