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Subject[PATCH 1/3] module: make it clear when we're handling the module copy in info->hdr
Date
In load_module(), it's not always clear whether we're handling the
temporary module copy in info->hdr (which is freed at the end of
load_module()) or if we're handling the module already allocated and
copied to it's final place. Adding an info->mod field and using it
whenever we're handling the temporary copy makes that explicitly clear.

Signed-off-by: Jessica Yu <jeyu@kernel.org>
---
kernel/module.c | 42 +++++++++++++++++++++---------------------
1 file changed, 21 insertions(+), 21 deletions(-)

diff --git a/kernel/module.c b/kernel/module.c
index 9c1709a05037..e8eba00bfed7 100644
--- a/kernel/module.c
+++ b/kernel/module.c
@@ -312,6 +312,8 @@ EXPORT_SYMBOL(unregister_module_notifier);

struct load_info {
const char *name;
+ /* pointer to module in temporary copy, freed at end of load_module() */
+ struct module *mod;
Elf_Ehdr *hdr;
unsigned long len;
Elf_Shdr *sechdrs;
@@ -2979,14 +2981,13 @@ static int rewrite_section_headers(struct load_info *info, int flags)
* search for module section index etc), and do some basic section
* verification.
*
- * Return the temporary module pointer (we'll replace it with the final
- * one when we move the module sections around).
+ * Set info->mod to the temporary copy of the module in info->hdr. The final one
+ * will be allocated in move_module().
*/
-static struct module *setup_load_info(struct load_info *info, int flags)
+static int setup_load_info(struct load_info *info, int flags)
{
unsigned int i;
int err;
- struct module *mod;

/* Set up the convenience variables */
info->sechdrs = (void *)info->hdr + info->hdr->e_shoff;
@@ -2995,7 +2996,7 @@ static struct module *setup_load_info(struct load_info *info, int flags)

err = rewrite_section_headers(info, flags);
if (err)
- return ERR_PTR(err);
+ return err;

/* Find internal symbols and strings. */
for (i = 1; i < info->hdr->e_shnum; i++) {
@@ -3012,30 +3013,30 @@ static struct module *setup_load_info(struct load_info *info, int flags)
if (!info->index.mod) {
pr_warn("%s: No module found in object\n",
info->name ?: "(missing .modinfo name field)");
- return ERR_PTR(-ENOEXEC);
+ return -ENOEXEC;
}
/* This is temporary: point mod into copy of data. */
- mod = (void *)info->sechdrs[info->index.mod].sh_addr;
+ info->mod = (void *)info->sechdrs[info->index.mod].sh_addr;

/*
* If we didn't load the .modinfo 'name' field, fall back to
* on-disk struct mod 'name' field.
*/
if (!info->name)
- info->name = mod->name;
+ info->name = info->mod->name;

if (info->index.sym == 0) {
pr_warn("%s: module has no symbols (stripped?)\n", info->name);
- return ERR_PTR(-ENOEXEC);
+ return -ENOEXEC;
}

info->index.pcpu = find_pcpusec(info);

/* Check module struct version now, before we try to use module. */
- if (!check_modstruct_version(info, mod))
- return ERR_PTR(-ENOEXEC);
+ if (!check_modstruct_version(info, info->mod))
+ return -ENOEXEC;

- return mod;
+ return 0;
}

static int check_modinfo(struct module *mod, struct load_info *info, int flags)
@@ -3330,25 +3331,24 @@ core_param(module_blacklist, module_blacklist, charp, 0400);

static struct module *layout_and_allocate(struct load_info *info, int flags)
{
- /* Module within temporary copy. */
struct module *mod;
unsigned int ndx;
int err;

- mod = setup_load_info(info, flags);
- if (IS_ERR(mod))
- return mod;
+ err = setup_load_info(info, flags);
+ if (err)
+ return ERR_PTR(err);

if (blacklisted(info->name))
return ERR_PTR(-EPERM);

- err = check_modinfo(mod, info, flags);
+ err = check_modinfo(info->mod, info, flags);
if (err)
return ERR_PTR(err);

/* Allow arches to frob section contents and sizes. */
err = module_frob_arch_sections(info->hdr, info->sechdrs,
- info->secstrings, mod);
+ info->secstrings, info->mod);
if (err < 0)
return ERR_PTR(err);

@@ -3367,11 +3367,11 @@ static struct module *layout_and_allocate(struct load_info *info, int flags)
/* Determine total sizes, and put offsets in sh_entsize. For now
this is done generically; there doesn't appear to be any
special cases for the architectures. */
- layout_sections(mod, info);
- layout_symtab(mod, info);
+ layout_sections(info->mod, info);
+ layout_symtab(info->mod, info);

/* Allocate and move to the final place */
- err = move_module(mod, info);
+ err = move_module(info->mod, info);
if (err)
return ERR_PTR(err);

--
2.16.3
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