libelf: section index 0 is special

When iterating over sections, table entry zero needs to be ignored.

Signed-off-by: Jan Beulich <jbeulich@suse.com>
Reviewed-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reviewed-by: Roger Pau Monné <roger.pau@citrix.com>

xen/common/libelf/libelf-dominfo.c

@@ -536,7 +536,7 @@ elf_errorstatus elf_xen_parse(struct elf_binary *elf,
     if ( xen_elfnotes == 0 )
     {
         count = elf_shdr_count(elf);
-        for ( i = 0; i < count; i++ )
+        for ( i = 1; i < count; i++ )
         {
             shdr = elf_shdr_by_index(elf, i);
             if ( !elf_access_ok(elf, ELF_HANDLE_PTRVAL(shdr), 1) )

xen/common/libelf/libelf-loader.c

@@ -79,7 +79,7 @@ elf_errorstatus elf_init(struct elf_binary *elf, const char *image_input, size_t
 
     /* Find symbol table and symbol string table. */
     count = elf_shdr_count(elf);
-    for ( i = 0; i < count; i++ )
+    for ( i = 1; i < count; i++ )
     {
         shdr = elf_shdr_by_index(elf, i);
         if ( !elf_access_ok(elf, ELF_HANDLE_PTRVAL(shdr), 1) )

xen/common/libelf/libelf-tools.c

@@ -153,7 +153,7 @@ ELF_HANDLE_DECL(elf_shdr) elf_shdr_by_name(struct elf_binary *elf, const char *n
     const char *sname;
     unsigned i;
 
-    for ( i = 0; i < count; i++ )
+    for ( i = 1; i < count; i++ )
     {
         shdr = elf_shdr_by_index(elf, i);
         if ( !elf_access_ok(elf, ELF_HANDLE_PTRVAL(shdr), 1) )