libpayload: verify LAR checksum

[Jordan Crouse]

This patch adds a libpayload function to verify the checksum on a
LAR blob.

Jordan

[Peter Stuge]

On Tue, May 27, 2008 at 01:44:01PM -0600, Jordan Crouse wrote:
> libpayload:  Add a function to verify the checksum on a LAR file
>
> This function verifies the checksum on a LAR file.
>
> Signed-off-by: Jordan Crouse

Acked-by: Peter Stuge
> Index: libpayload/include/libpayload.h
>
> --- libpayload.orig/include/libpayload.h	2008-05-14 09:23:10.000000000 -0600
> +++ libpayload/include/libpayload.h	2008-05-14 09:28:39.000000000 -0600
> @@ -251,6 +251,7 @@
>  void rewindlar(struct LAR *lar);
>  int larstat(struct LAR *lar, const char *path, struct larstat *buf);
>  void *larfptr(struct LAR *lar, const char *filename);
> +int lfverify(struct LAR *lar, const char *filename);
>  struct LFILE * lfopen(struct LAR *lar, const char *filename);
>  int lfread(void *ptr, size_t size, size_t nmemb, struct LFILE *stream);
> Index: libpayload/libc/lar.c
>
> --- libpayload.orig/libc/lar.c	2008-05-14 09:18:30.000000000 -0600
> +++ libpayload/libc/lar.c	2008-05-14 10:52:39.000000000 -0600
> @@ -228,6 +228,41 @@
>    return (void *) ((u8 *) header + ntohl(header->offset));
>  }
>
> +/**
> Verify the checksum on a particular LAR entry
> @param lar A pointer to the LAR stream
> @param filename The lar entry to verify
> @return Return 1 if the entry is valid, 0 if it is not, or -1
> on error
> */
>
> +int lfverify(struct LAR *lar, const char *filename)
> +{
> struct lar_header *header = get_header_by_name(lar, filename);
> u8 *ptr = (u8 *) header;
> int len = ntohl(header->len) + ntohl(header->offset);
> int offset;
> u32 csum = 0;
> if (header == NULL)
> return -1;
> /* The checksum needs to be calulated on entire data section,
> * including any padding for the 16 byte alignment (which should
> * be zeros
> */
> len = (len + 15) & 0xFFFFFFF0;
> for(offset = 0; offset < len; offset += 4) {
> csum += *((u32 *) (ptr + offset));
> }
> return (csum == 0xFFFFFFFF) ? 1 : 0;
>
> +}
>
> struct LFILE * lfopen(struct LAR *lar, const char *filename)
>  {
>    struct LFILE *file;

[Jordan Crouse]

On 27/05/08 21:52 +0200, Peter Stuge wrote:
> On Tue, May 27, 2008 at 01:44:01PM -0600, Jordan Crouse wrote:
> > libpayload:  Add a function to verify the checksum on a LAR file
> >
> > This function verifies the checksum on a LAR file.
> >
> > Signed-off-by: Jordan Crouse
>
> Acked-by: Peter Stuge

r3352.  Thanks.
> > Index: libpayload/include/libpayload.h
> >
> > --- libpayload.orig/include/libpayload.h	2008-05-14 09:23:10.000000000 -0600
> > +++ libpayload/include/libpayload.h	2008-05-14 09:28:39.000000000 -0600
> > @@ -251,6 +251,7 @@
> >  void rewindlar(struct LAR *lar);
> >  int larstat(struct LAR *lar, const char *path, struct larstat *buf);
> >  void *larfptr(struct LAR *lar, const char *filename);
> > +int lfverify(struct LAR *lar, const char *filename);
> >  struct LFILE * lfopen(struct LAR *lar, const char *filename);
> >  int lfread(void *ptr, size_t size, size_t nmemb, struct LFILE *stream);
> > Index: libpayload/libc/lar.c
> >
> > --- libpayload.orig/libc/lar.c	2008-05-14 09:18:30.000000000 -0600
> > +++ libpayload/libc/lar.c	2008-05-14 10:52:39.000000000 -0600
> > @@ -228,6 +228,41 @@
> >    return (void *) ((u8 *) header + ntohl(header->offset));
> >  }
> >
> > +/**
> > Verify the checksum on a particular LAR entry
> > @param lar A pointer to the LAR stream
> > @param filename The lar entry to verify
> > @return Return 1 if the entry is valid, 0 if it is not, or -1
> > on error
> > */
> >
> > +int lfverify(struct LAR *lar, const char *filename)
> > +{
> > struct lar_header *header = get_header_by_name(lar, filename);
> > u8 *ptr = (u8 *) header;
> > int len = ntohl(header->len) + ntohl(header->offset);
> > int offset;
> > u32 csum = 0;
> > if (header == NULL)
> > return -1;
> > /* The checksum needs to be calulated on entire data section,
> > * including any padding for the 16 byte alignment (which should
> > * be zeros
> > */
> > len = (len + 15) & 0xFFFFFFF0;
> > for(offset = 0; offset < len; offset += 4) {
> > csum += *((u32 *) (ptr + offset));
> > }
> > return (csum == 0xFFFFFFFF) ? 1 : 0;
> >
> > +}
> >
> > struct LFILE * lfopen(struct LAR *lar, const char *filename)
> >  {
> >    struct LFILE *file;