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_info
Centralize .modinfo detection and property validation.
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
fbc0e4e4
3c5700ae
+68
-14
+68
-14
kernel/module/main.c
+68
-14
kernel/module/main.c
···
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return 0;
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}
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+
/**
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* find_any_unique_sec() - Find a unique section index by name
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* @info: Load info for the module to scan
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* @name: Name of the section we're looking for
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*
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* Locates a unique section by name. Ignores SHF_ALLOC.
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*
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* Return: Section index if found uniquely, zero if absent, negative count
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* of total instances if multiple were found.
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*/
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static int find_any_unique_sec(const struct load_info *info, const char *name)
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{
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unsigned int idx;
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unsigned int count = 0;
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int i;
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+
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for (i = 1; i < info->hdr->e_shnum; i++) {
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if (strcmp(info->secstrings + info->sechdrs[i].sh_name,
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name) == 0) {
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count++;
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idx = i;
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}
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}
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if (count == 1) {
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return idx;
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} else if (count == 0) {
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return 0;
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} else {
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return -count;
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}
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}
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/* Find a module section, or NULL. */
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static void *section_addr(const struct load_info *info, const char *name)
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{
···
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return 0;
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}
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/**
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* elf_validity_cache_index_info() - Validate and cache modinfo section
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* @info: Load info to populate the modinfo index on.
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* Must have &load_info->sechdrs and &load_info->secstrings populated
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*
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* Checks that if there is a .modinfo section, it is unique.
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* Then, it caches its index in &load_info->index.info.
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* Finally, it tries to populate the name to improve error messages.
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*
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* Return: %0 if valid, %-ENOEXEC if multiple modinfo sections were found.
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*/
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static int elf_validity_cache_index_info(struct load_info *info)
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{
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int info_idx;
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info_idx = find_any_unique_sec(info, ".modinfo");
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if (info_idx == 0)
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/* Early return, no .modinfo */
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return 0;
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+
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if (info_idx < 0) {
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pr_err("Only one .modinfo section must exist.\n");
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return -ENOEXEC;
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}
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info->index.info = info_idx;
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/* Try to find a name early so we can log errors with a module name */
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info->name = get_modinfo(info, "name");
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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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Elf_Shdr *shdr;
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int err;
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unsigned int num_mod_secs = 0, mod_idx;
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-
unsigned int num_info_secs = 0, info_idx;
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unsigned int num_sym_secs = 0, sym_idx;
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err = elf_validity_cache_sechdrs(info);
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if (err < 0)
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return err;
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err = elf_validity_cache_secstrings(info);
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if (err < 0)
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return err;
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err = elf_validity_cache_index_info(info);
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if (err < 0)
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return err;
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···
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".gnu.linkonce.this_module") == 0) {
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num_mod_secs++;
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mod_idx = i;
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-
} else if (strcmp(info->secstrings + shdr->sh_name,
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".modinfo") == 0) {
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num_info_secs++;
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info_idx = i;
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}
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break;
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}
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}
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if (num_info_secs > 1) {
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pr_err("Only one .modinfo section must exist.\n");
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goto no_exec;
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} else if (num_info_secs == 1) {
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/* Try to find a name early so we can log errors with a module name */
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info->index.info = info_idx;
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info->name = get_modinfo(info, "name");
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}
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if (num_sym_secs != 1) {