Re: [PATCH] readnote: Add bzImage kernel support

[Xuesen Guo <Xuesen.Guo@hitachiconsulting.com>]

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Also the attached is the patch.

On Mon, 2012-05-28 at 14:03 +0800, Xuesen Guo wrote:
> I used the Evolution(GUI) sending patches manually, this might mangle the whitespace of a patch making it impossible to apply.
> According to Linux's email-clients.txt, I resend this patch.
> 
> # HG changeset patch
> # Parent d690c7e896a26c54a5ab85458824059de72d5cba
> readnote: Add bzImage kernel support
> 
> Add the check of bzImage kernel and make it work
> with RHEL 6 big zImage kernel
> 
> Signed-off-by: Xuesen Guo <Xuesen.Guo@hitachiconsulting.com>
> Acked-by: Ian Campbell <ian.campbell@citrix.com>
> 
> ---
> Changed since v1:
>   * add additional checks of the offset and length
>   * not changing st.st_size, use size instead of st.st_size
>   
> ---
> Changed since v2:
>   * changing decription bzipped kernels to big zImage kernel
> 
> diff -r d690c7e896a2 tools/xcutils/readnotes.c
> --- a/tools/xcutils/readnotes.c	Thu Apr 05 11:06:03 2012 +0100
> +++ b/tools/xcutils/readnotes.c	Thu Apr 26 16:53:16 2012 +0800
> @@ -18,6 +18,48 @@
>  
>  static xc_interface *xch;
>  
> +/* According to the implemation of xc_dom_probe_bzimage_kernel() function */
> +/* We add support of bzImage kernel */
> +/* Copied from tools/libxc/xc_doom_bzImageloader.c */
> +struct setup_header {
> +	uint8_t  _pad0[0x1f1];  /* skip uninteresting stuff */
> +	uint8_t  setup_sects;
> +	uint16_t root_flags;
> +	uint32_t syssize;
> +	uint16_t ram_size;
> +	uint16_t vid_mode;
> +	uint16_t root_dev;
> +	uint16_t boot_flag;
> +	uint16_t jump;
> +	uint32_t header;
> +#define HDR_MAGIC  "HdrS"
> +#define HDR_MAGIC_SZ 4
> +	uint16_t version;
> +#define VERSION(h,l) (((h)<<8) | (l))
> +	uint32_t realmode_swtch;
> +	uint16_t start_sys;
> +	uint16_t kernel_version;
> +	uint8_t  type_of_loader;
> +	uint8_t  loadflags;
> +	uint16_t setup_move_size;
> +	uint32_t code32_start;
> +	uint32_t ramdisk_image;
> +	uint32_t ramdisk_size;
> +	uint32_t bootsect_kludge;
> +	uint16_t heap_end_ptr;
> +	uint16_t _pad1;
> +	uint32_t cmd_line_ptr;
> +	uint32_t initrd_addr_max;
> +	uint32_t kernel_alignment;
> +	uint8_t  relocatable_kernel;
> +	uint8_t  _pad2[3];
> +	uint32_t cmdline_size;
> +	uint32_t hardware_subarch;
> +	uint64_t hardware_subarch_data;
> +	uint32_t payload_offset;
> +	uint32_t payload_length;
> +} __attribute__((packed));
> +
>  static void print_string_note(const char *prefix, struct elf_binary *elf,
>  			      const elf_note *note)
>  {
> @@ -131,6 +173,9 @@ int main(int argc, char **argv)
>  	const elf_shdr *shdr;
>  	int notes_found = 0;
>  
> +	struct setup_header *hdr;
> +	uint64_t payload_offset, payload_length;
> +
>  	if (argc != 2)
>  	{
>  		fprintf(stderr, "Usage: readnotes <elfimage>\n");
> @@ -159,13 +204,45 @@ int main(int argc, char **argv)
>  		fprintf(stderr, "Unable to map %s: %s\n", f, strerror(errno));
>  		return 1;
>  	}
> -	size = st.st_size;
> +	
> +	/* Check the magic of bzImage kernel */
> +	hdr = (struct setup_header *)image;
> +	if ( memcmp(&hdr->header, HDR_MAGIC, HDR_MAGIC_SZ) == 0 )
> +	{
> +		if ( hdr->version < VERSION(2,8) )
> +		{
> +			printf("%s: boot protocol too old (%04x)", __FUNCTION__, hdr->version);
> +			return 1;
> +		}
>  
> -	usize = xc_dom_check_gzip(xch, image, st.st_size);
> +		/* upcast to 64 bits to avoid overflow */
> +		/* setup_sects is u8 and so cannot overflow */
> +		payload_offset = (hdr->setup_sects + 1) * 512;
> +		payload_offset += hdr->payload_offset;
> +		payload_length = hdr->payload_length;
> +		
> +		if ( payload_offset >= st.st_size )
> +		{
> +			printf("%s: payload offset overflow", __FUNCTION__);
> +			return 1;
> +		}
> +		if ( (payload_offset + payload_length) > st.st_size )
> +		{
> +			printf("%s: payload length overflow", __FUNCTION__);
> +			return 1;
> +		}
> +
> +		image = image + payload_offset;
> +		size = payload_length;
> +	} else {
> +		size = st.st_size;
> +	}
> +
> +	usize = xc_dom_check_gzip(xch, image, size);
>  	if (usize)
>  	{
>  		tmp = malloc(usize);
> -		xc_dom_do_gunzip(xch, image, st.st_size, tmp, usize);
> +		xc_dom_do_gunzip(xch, image, size, tmp, usize);
>  		image = tmp;
>  		size = usize;
>  	}
> 
> 
> On Fri, 2012-05-11 at 17:49 +0100, Ian Campbell wrote:
> > On Fri, 2012-05-11 at 17:43 +0100, Ian Jackson wrote:
> > > Xuesen Guo writes ("Re: [Xen-devel] [PATCH] readnote: Add bzImage kernel support"):
> > > > readnote: Add bzImage kernel support
> > > 
> > > I tried to apply this but I'm afraid it no longer applies to
> > > xen-unstable tip:
> > > 
> > > patching file tools/xcutils/readnotes.c
> > > Hunk #1 FAILED at 17
> > > Hunk #3 FAILED at 161
> > > 2 out of 3 hunks FAILED -- saving rejects to file tools/xcutils/readnotes.c.rej
> > > abort: patch failed to apply
> > > 
> > > Ian.
> > 
> > The most recent change to this file was 
> >         changeset:   21483:779c0ef9682c
> >         user:        Keir Fraser <keir.fraser@citrix.com>
> >         date:        Fri May 28 09:30:19 2010 +0100
> >         summary:     libxc: eliminate static variables, use xentoollog; API change
> >         
> > I expect something else is up -- whitespace mangling perhaps? Or maybe
> > the patch simply isn't based on xen-unstable.hg?
> > 
> > Ian.
> > 
> > 
> 

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# HG changeset patch
# Parent d690c7e896a26c54a5ab85458824059de72d5cba
readnote: Add bzImage kernel support

Add the check of bzImage kernel and make it work
with RHEL 6 big zImage kernel

Signed-off-by: Xuesen Guo <Xuesen.Guo@hitachiconsulting.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>

---
Changed since v1:
  * add additional checks of the offset and length
  * not changing st.st_size, use size instead of st.st_size
  
---
Changed since v2:
  * changing decription bzipped kernels to big zImage kernel

diff -r d690c7e896a2 tools/xcutils/readnotes.c
--- a/tools/xcutils/readnotes.c	Thu Apr 05 11:06:03 2012 +0100
+++ b/tools/xcutils/readnotes.c	Thu Apr 26 16:53:16 2012 +0800
@@ -18,6 +18,48 @@
 
 static xc_interface *xch;
 
+/* According to the implemation of xc_dom_probe_bzimage_kernel() function */
+/* We add support of bzImage kernel */
+/* Copied from tools/libxc/xc_doom_bzImageloader.c */
+struct setup_header {
+	uint8_t  _pad0[0x1f1];  /* skip uninteresting stuff */
+	uint8_t  setup_sects;
+	uint16_t root_flags;
+	uint32_t syssize;
+	uint16_t ram_size;
+	uint16_t vid_mode;
+	uint16_t root_dev;
+	uint16_t boot_flag;
+	uint16_t jump;
+	uint32_t header;
+#define HDR_MAGIC  "HdrS"
+#define HDR_MAGIC_SZ 4
+	uint16_t version;
+#define VERSION(h,l) (((h)<<8) | (l))
+	uint32_t realmode_swtch;
+	uint16_t start_sys;
+	uint16_t kernel_version;
+	uint8_t  type_of_loader;
+	uint8_t  loadflags;
+	uint16_t setup_move_size;
+	uint32_t code32_start;
+	uint32_t ramdisk_image;
+	uint32_t ramdisk_size;
+	uint32_t bootsect_kludge;
+	uint16_t heap_end_ptr;
+	uint16_t _pad1;
+	uint32_t cmd_line_ptr;
+	uint32_t initrd_addr_max;
+	uint32_t kernel_alignment;
+	uint8_t  relocatable_kernel;
+	uint8_t  _pad2[3];
+	uint32_t cmdline_size;
+	uint32_t hardware_subarch;
+	uint64_t hardware_subarch_data;
+	uint32_t payload_offset;
+	uint32_t payload_length;
+} __attribute__((packed));
+
 static void print_string_note(const char *prefix, struct elf_binary *elf,
 			      const elf_note *note)
 {
@@ -131,6 +173,9 @@ int main(int argc, char **argv)
 	const elf_shdr *shdr;
 	int notes_found = 0;
 
+	struct setup_header *hdr;
+	uint64_t payload_offset, payload_length;
+
 	if (argc != 2)
 	{
 		fprintf(stderr, "Usage: readnotes <elfimage>\n");
@@ -159,13 +204,45 @@ int main(int argc, char **argv)
 		fprintf(stderr, "Unable to map %s: %s\n", f, strerror(errno));
 		return 1;
 	}
-	size = st.st_size;
+	
+	/* Check the magic of bzImage kernel */
+	hdr = (struct setup_header *)image;
+	if ( memcmp(&hdr->header, HDR_MAGIC, HDR_MAGIC_SZ) == 0 )
+	{
+		if ( hdr->version < VERSION(2,8) )
+		{
+			printf("%s: boot protocol too old (%04x)", __FUNCTION__, hdr->version);
+			return 1;
+		}
 
-	usize = xc_dom_check_gzip(xch, image, st.st_size);
+		/* upcast to 64 bits to avoid overflow */
+		/* setup_sects is u8 and so cannot overflow */
+		payload_offset = (hdr->setup_sects + 1) * 512;
+		payload_offset += hdr->payload_offset;
+		payload_length = hdr->payload_length;
+		
+		if ( payload_offset >= st.st_size )
+		{
+			printf("%s: payload offset overflow", __FUNCTION__);
+			return 1;
+		}
+		if ( (payload_offset + payload_length) > st.st_size )
+		{
+			printf("%s: payload length overflow", __FUNCTION__);
+			return 1;
+		}
+
+		image = image + payload_offset;
+		size = payload_length;
+	} else {
+		size = st.st_size;
+	}
+
+	usize = xc_dom_check_gzip(xch, image, size);
 	if (usize)
 	{
 		tmp = malloc(usize);
-		xc_dom_do_gunzip(xch, image, st.st_size, tmp, usize);
+		xc_dom_do_gunzip(xch, image, size, tmp, usize);
 		image = tmp;
 		size = usize;
 	}

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