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util/grub-module-verifierXX: Add function to calculate section headers

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Added the function get_shdr() which returns the section header at a given index
parameter passed into this function. This helps traverse the section header
table and reduces repeated calls to lengthy equations used to obtain section
headers.

Note that it may look as though the argument *arch isn't being used, it's
actually required in order to use the macros grub_target_to_host*(x) which are
unwinded to grub_target_to_host*_real(arch, (x)) based on defines earlier in the
file.

Signed-off-by: Alec Brown <alec.r.brown@oracle.com>
Reviewed-by: Darren Kenny <darren.kenny@oracle.com>
Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>
This commit is contained in:
Alec Brown 2022-02-02 19:26:57 -05:00 committed by Daniel Kiper
parent ebf32bc4e9
commit e92633850c
1 changed files with 15 additions and 10 deletions
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25
util/grub-module-verifierXX.c
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@ -131,6 +131,12 @@ grub_target_to_host_real (const struct grub_module_verifier_arch *arch, grub_uin
return grub_target_to_host32_real (arch, in);
}
static Elf_Shdr *
get_shdr (const struct grub_module_verifier_arch *arch, Elf_Ehdr *e, Elf_Word index)
{
return (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff) +
index * grub_target_to_host16 (e->e_shentsize));
}
static Elf_Shdr *
find_section (const struct grub_module_verifier_arch *arch, Elf_Ehdr *e, const char *name)
@ -139,12 +145,12 @@ find_section (const struct grub_module_verifier_arch *arch, Elf_Ehdr *e, const c
const char *str;
unsigned i;
s = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff) + grub_target_to_host16 (e->e_shstrndx) * grub_target_to_host16 (e->e_shentsize));
s = get_shdr (arch, e, grub_target_to_host16 (e->e_shstrndx));
str = (char *) e + grub_target_to_host (s->sh_offset);
for (i = 0, s = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff));
for (i = 0, s = get_shdr (arch, e, 0);
i < grub_target_to_host16 (e->e_shnum);
i++, s = (Elf_Shdr *) ((char *) s + grub_target_to_host16 (e->e_shentsize)))
i++, s = get_shdr (arch, e, i))
if (strcmp (str + grub_target_to_host32 (s->sh_name), name) == 0)
return s;
return NULL;
@ -166,13 +172,12 @@ static Elf_Sym *
get_symtab (const struct grub_module_verifier_arch *arch, Elf_Ehdr *e, Elf_Word *size, Elf_Word *entsize)
{
unsigned i;
Elf_Shdr *s, *sections;
Elf_Shdr *s;
Elf_Sym *sym;
sections = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff));
for (i = 0, s = sections;
for (i = 0, s = get_shdr (arch, e, 0);
i < grub_target_to_host16 (e->e_shnum);
i++, s = (Elf_Shdr *) ((char *) s + grub_target_to_host16 (e->e_shentsize)))
i++, s = get_shdr (arch, e, i))
if (grub_target_to_host32 (s->sh_type) == SHT_SYMTAB)
break;
@ -364,9 +369,9 @@ check_relocations (const char * const modname,
Elf_Shdr *s;
unsigned i;
for (i = 0, s = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff));
for (i = 0, s = get_shdr (arch, e, 0);
i < grub_target_to_host16 (e->e_shnum);
i++, s = (Elf_Shdr *) ((char *) s + grub_target_to_host16 (e->e_shentsize)))
i++, s = get_shdr (arch, e, i))
if (grub_target_to_host32 (s->sh_type) == SHT_REL || grub_target_to_host32 (s->sh_type) == SHT_RELA)
{
Elf_Shdr *ts;
@ -379,7 +384,7 @@ check_relocations (const char * const modname,
/* Find the target segment. */
if (grub_target_to_host32 (s->sh_info) >= grub_target_to_host16 (e->e_shnum))
grub_util_error ("%s: orphaned reloc section", modname);
ts = (Elf_Shdr *) ((char *) e + grub_target_to_host (e->e_shoff) + grub_target_to_host32 (s->sh_info) * grub_target_to_host16 (e->e_shentsize));
ts = get_shdr (arch, e, grub_target_to_host32 (s->sh_info));
section_check_relocations (modname, arch, e, s, grub_target_to_host (ts->sh_size));
}