Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
module: Factor out elf_validity_cache_index_str
Pull out index validation for the symbol string section.
Note that this does not validate the *contents* of the string table,
only shape and presence of the section.
Signed-off-by: Matthew Maurer <mmaurer@google.com>
Reviewed-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
authored by
Matthew Maurer
and committed by
Luis Chamberlain
0a939533
9bd4982c
+28
-9
+28
-9
kernel/module/main.c
+28
-9
kernel/module/main.c
···
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return 0;
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}
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+
/**
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* elf_validity_cache_index_str() - Validate and cache strtab index
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* @info: Load info to cache strtab index in.
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* Must have &load_info->sechdrs and &load_info->secstrings populated.
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* Must have &load_info->index.sym populated.
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*
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* Looks at the symbol table's associated string table, makes sure it is
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* in-bounds, and caches it.
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*
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* Return: %0 if valid, %-ENOEXEC on failure.
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*/
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static int elf_validity_cache_index_str(struct load_info *info)
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{
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unsigned int str_idx = info->sechdrs[info->index.sym].sh_link;
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if (str_idx == SHN_UNDEF || str_idx >= info->hdr->e_shnum) {
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pr_err("Invalid ELF sh_link!=SHN_UNDEF(%d) or (sh_link(%d) >= hdr->e_shnum(%d)\n",
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str_idx, str_idx, info->hdr->e_shnum);
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return -ENOEXEC;
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}
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info->index.str = str_idx;
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return 0;
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}
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/*
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* Check userspace passed ELF module against our expectations, and cache
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* useful variables for further processing as we go.
···
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static int elf_validity_cache_copy(struct load_info *info, int flags)
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{
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int err;
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-
int str_idx;
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err = elf_validity_cache_sechdrs(info);
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if (err < 0)
···
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err = elf_validity_cache_index_sym(info);
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if (err < 0)
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return err;
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-
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str_idx = info->sechdrs[info->index.sym].sh_link;
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if (str_idx == SHN_UNDEF || str_idx >= info->hdr->e_shnum) {
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pr_err("Invalid ELF sh_link!=SHN_UNDEF(%d) or (sh_link(%d) >= hdr->e_shnum(%d)\n",
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str_idx, str_idx, info->hdr->e_shnum);
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return -ENOEXEC;
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-
}
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err = elf_validity_cache_index_str(info);
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if (err < 0)
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return err;
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/* Sets internal strings. */
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info->index.str = str_idx;
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info->strtab = (char *)info->hdr + info->sechdrs[info->index.str].sh_offset;
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/* This is temporary: point mod into copy of data. */