@@ -355,6 +355,24 @@ static void dedotify_versions(struct modversion_info *vers,
}
}
+/* Same as normal versions, remove a leading dot if present. */
+static void dedotify_ext_version_names(char *str_seq, unsigned long size)
+{
+ unsigned long out = 0;
+ unsigned long in;
+ char last = '\0';
+
+ for (in = 0; in < size; in++) {
+ /* Skip one leading dot */
+ if (last == '\0' && str_seq[in] == '.')
+ in++;
+ last = str_seq[in];
+ str_seq[out++] = last;
+ }
+ /* Zero the trailing portion of the names table for robustness */
+ memset(&str_seq[out], 0, size - out);
+}
+
/*
* Undefined symbols which refer to .funcname, hack to funcname. Make .TOC.
* seem to be defined (value set later).
@@ -424,10 +442,12 @@ int module_frob_arch_sections(Elf64_Ehdr *hdr,
me->arch.toc_section = i;
if (sechdrs[i].sh_addralign < 8)
sechdrs[i].sh_addralign = 8;
- }
- else if (strcmp(secstrings+sechdrs[i].sh_name,"__versions")==0)
+ } else if (strcmp(secstrings + sechdrs[i].sh_name, "__versions") == 0)
dedotify_versions((void *)hdr + sechdrs[i].sh_offset,
sechdrs[i].sh_size);
+ else if (strcmp(secstrings + sechdrs[i].sh_name, "__version_ext_names") == 0)
+ dedotify_ext_version_names((void *)hdr + sechdrs[i].sh_offset,
+ sechdrs[i].sh_size);
if (sechdrs[i].sh_type == SHT_SYMTAB)
dedotify((void *)hdr + sechdrs[i].sh_offset,
@@ -86,6 +86,8 @@ struct load_info {
unsigned int vers;
unsigned int info;
unsigned int pcpu;
+ unsigned int vers_ext_crc;
+ unsigned int vers_ext_name;
} index;
};
@@ -389,6 +391,15 @@ void module_layout(struct module *mod, struct modversion_info *ver, struct kerne
struct kernel_symbol *ks, struct tracepoint * const *tp);
int check_modstruct_version(const struct load_info *info, struct module *mod);
int same_magic(const char *amagic, const char *bmagic, bool has_crcs);
+struct modversion_info_ext {
+ size_t remaining;
+ const s32 *crc;
+ const char *name;
+};
+void modversion_ext_start(const struct load_info *info, struct modversion_info_ext *ver);
+void modversion_ext_advance(struct modversion_info_ext *ver);
+#define for_each_modversion_info_ext(ver, info) \
+ for (modversion_ext_start(info, &ver); ver.remaining > 0; modversion_ext_advance(&ver))
#else /* !CONFIG_MODVERSIONS */
static inline int check_version(const struct load_info *info,
const char *symname,
@@ -2039,6 +2039,82 @@ static int elf_validity_cache_index_str(struct load_info *info)
return 0;
}
+/**
+ * elf_validity_cache_index_versions() - Validate and cache version indices
+ * @info: Load info to cache version indices in.
+ * Must have &load_info->sechdrs and &load_info->secstrings populated.
+ * @flags: Load flags, relevant to suppress version loading, see
+ * uapi/linux/module.h
+ *
+ * If we're ignoring modversions based on @flags, zero all version indices
+ * and return validity. Othewrise check:
+ *
+ * * If "__version_ext_crcs" is present, "__version_ext_names" is present
+ * * There is a name present for every crc
+ *
+ * Then populate:
+ *
+ * * &load_info->index.vers
+ * * &load_info->index.vers_ext_crc
+ * * &load_info->index.vers_ext_names
+ *
+ * if present.
+ *
+ * Return: %0 if valid, %-ENOEXEC on failure.
+ */
+static int elf_validity_cache_index_versions(struct load_info *info, int flags)
+{
+ unsigned int vers_ext_crc;
+ unsigned int vers_ext_name;
+ size_t crc_count;
+ size_t remaining_len;
+ size_t name_size;
+ char *name;
+
+ /* If modversions were suppressed, pretend we didn't find any */
+ if (flags & MODULE_INIT_IGNORE_MODVERSIONS) {
+ info->index.vers = 0;
+ info->index.vers_ext_crc = 0;
+ info->index.vers_ext_name = 0;
+ return 0;
+ }
+
+ vers_ext_crc = find_sec(info, "__version_ext_crcs");
+ vers_ext_name = find_sec(info, "__version_ext_names");
+
+ /* If we have one field, we must have the other */
+ if (!!vers_ext_crc != !!vers_ext_name) {
+ pr_err("extended version crc+name presence does not match");
+ return -ENOEXEC;
+ }
+
+ /*
+ * If we have extended version information, we should have the same
+ * number of entries in every section.
+ */
+ if (vers_ext_crc) {
+ crc_count = info->sechdrs[vers_ext_crc].sh_size / sizeof(s32);
+ name = (void *)info->hdr +
+ info->sechdrs[vers_ext_name].sh_offset;
+ remaining_len = info->sechdrs[vers_ext_name].sh_size;
+
+ while (crc_count--) {
+ name_size = strnlen(name, remaining_len) + 1;
+ if (name_size > remaining_len) {
+ pr_err("more extended version crcs than names");
+ return -ENOEXEC;
+ }
+ remaining_len -= name_size;
+ name += name_size;
+ }
+ }
+
+ info->index.vers = find_sec(info, "__versions");
+ info->index.vers_ext_crc = vers_ext_crc;
+ info->index.vers_ext_name = vers_ext_name;
+ return 0;
+}
+
/**
* elf_validity_cache_index() - Resolve, validate, cache section indices
* @info: Load info to read from and update.
@@ -2053,9 +2129,7 @@ static int elf_validity_cache_index_str(struct load_info *info)
* * elf_validity_cache_index_mod()
* * elf_validity_cache_index_sym()
* * elf_validity_cache_index_str()
- *
- * If versioning is not suppressed via flags, load the version index from
- * a section called "__versions" with no validation.
+ * * elf_validity_cache_index_versions()
*
* If CONFIG_SMP is enabled, load the percpu section by name with no
* validation.
@@ -2078,11 +2152,9 @@ static int elf_validity_cache_index(struct load_info *info, int flags)
err = elf_validity_cache_index_str(info);
if (err < 0)
return err;
-
- if (flags & MODULE_INIT_IGNORE_MODVERSIONS)
- info->index.vers = 0; /* Pretend no __versions section! */
- else
- info->index.vers = find_sec(info, "__versions");
+ err = elf_validity_cache_index_versions(info, flags);
+ if (err < 0)
+ return err;
info->index.pcpu = find_pcpusec(info);
@@ -2293,6 +2365,10 @@ static int rewrite_section_headers(struct load_info *info, int flags)
/* Track but don't keep modinfo and version sections. */
info->sechdrs[info->index.vers].sh_flags &= ~(unsigned long)SHF_ALLOC;
+ info->sechdrs[info->index.vers_ext_crc].sh_flags &=
+ ~(unsigned long)SHF_ALLOC;
+ info->sechdrs[info->index.vers_ext_name].sh_flags &=
+ ~(unsigned long)SHF_ALLOC;
info->sechdrs[info->index.info].sh_flags &= ~(unsigned long)SHF_ALLOC;
return 0;
@@ -19,11 +19,28 @@ int check_version(const struct load_info *info,
unsigned int versindex = info->index.vers;
unsigned int i, num_versions;
struct modversion_info *versions;
+ struct modversion_info_ext version_ext;
/* Exporting module didn't supply crcs? OK, we're already tainted. */
if (!crc)
return 1;
+ /* If we have extended version info, rely on it */
+ if (info->index.vers_ext_crc) {
+ for_each_modversion_info_ext(version_ext, info) {
+ if (strcmp(version_ext.name, symname) != 0)
+ continue;
+ if (*version_ext.crc == *crc)
+ return 1;
+ pr_debug("Found checksum %X vs module %X\n",
+ *crc, *version_ext.crc);
+ goto bad_version;
+ }
+ pr_warn_once("%s: no extended symbol version for %s\n",
+ info->name, symname);
+ return 1;
+ }
+
/* No versions at all? modprobe --force does this. */
if (versindex == 0)
return try_to_force_load(mod, symname) == 0;
@@ -87,6 +104,34 @@ int same_magic(const char *amagic, const char *bmagic,
return strcmp(amagic, bmagic) == 0;
}
+void modversion_ext_start(const struct load_info *info,
+ struct modversion_info_ext *start)
+{
+ unsigned int crc_idx = info->index.vers_ext_crc;
+ unsigned int name_idx = info->index.vers_ext_name;
+ Elf_Shdr *sechdrs = info->sechdrs;
+
+ /*
+ * Both of these fields are needed for this to be useful
+ * Any future fields should be initialized to NULL if absent.
+ */
+ if (crc_idx == 0 || name_idx == 0) {
+ start->remaining = 0;
+ return;
+ }
+
+ start->crc = (const s32 *)sechdrs[crc_idx].sh_addr;
+ start->name = (const char *)sechdrs[name_idx].sh_addr;
+ start->remaining = sechdrs[crc_idx].sh_size / sizeof(*start->crc);
+}
+
+void modversion_ext_advance(struct modversion_info_ext *vers)
+{
+ vers->remaining--;
+ vers->crc++;
+ vers->name += strlen(vers->name) + 1;
+}
+
/*
* Generate the signature for all relevant module structures here.
* If these change, we don't want to try to parse the module.