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livepatch/module: make TAINT_LIVEPATCH module-specific

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There's no reliable way to determine which module tainted the kernel
with TAINT_LIVEPATCH.  For example, /sys/module/<klp module>/taint
doesn't report it.  Neither does the "mod -t" command in the crash tool.

Make it crystal clear who the guilty party is by associating
TAINT_LIVEPATCH with any module which sets the "livepatch" modinfo
attribute.  The flag will still get set in the kernel like before, but
now it also sets the same flag in mod->taint.

Note that now the taint flag gets set when the module is loaded rather
than when it's enabled.

I also renamed find_livepatch_modinfo() to check_modinfo_livepatch() to
better reflect its purpose: it's basically a livepatch-specific
sub-function of check_modinfo().

Reported-by: Chunyu Hu <chuhu@redhat.com>
Reviewed-by: Petr Mladek <pmladek@suse.com>
Acked-by: Miroslav Benes <mbenes@suse.cz>
Acked-by: Jessica Yu <jeyu@redhat.com>
Acked-by: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This commit is contained in:
Josh Poimboeuf 2016-08-25 10:04:45 -05:00 committed by Jiri Kosina
parent 5ad75fcdd7
commit 2992ef29ae
2 changed files with 9 additions and 7 deletions
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3
kernel/livepatch/core.c
View File

@ -545,9 +545,6 @@ static int __klp_enable_patch(struct klp_patch *patch)
list_prev_entry(patch, list)->state == KLP_DISABLED)
return -EBUSY;
pr_notice_once("tainting kernel with TAINT_LIVEPATCH\n");
add_taint(TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
pr_notice("enabling patch '%s'\n", patch->mod->name);
klp_for_each_object(patch, obj) {

13
kernel/module.c
View File

@ -1149,6 +1149,8 @@ static size_t module_flags_taint(struct module *mod, char *buf)
buf[l++] = 'C';
if (mod->taints & (1 << TAINT_UNSIGNED_MODULE))
buf[l++] = 'E';
if (mod->taints & (1 << TAINT_LIVEPATCH))
buf[l++] = 'K';
/*
* TAINT_FORCED_RMMOD: could be added.
* TAINT_CPU_OUT_OF_SPEC, TAINT_MACHINE_CHECK, TAINT_BAD_PAGE don't
@ -2792,14 +2794,17 @@ static int copy_chunked_from_user(void *dst, const void __user *usrc, unsigned l
}
#ifdef CONFIG_LIVEPATCH
static int find_livepatch_modinfo(struct module *mod, struct load_info *info)
static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
{
mod->klp = get_modinfo(info, "livepatch") ? true : false;
if (get_modinfo(info, "livepatch")) {
mod->klp = true;
add_taint_module(mod, TAINT_LIVEPATCH, LOCKDEP_STILL_OK);
}
return 0;
}
#else /* !CONFIG_LIVEPATCH */
static int find_livepatch_modinfo(struct module *mod, struct load_info *info)
static int check_modinfo_livepatch(struct module *mod, struct load_info *info)
{
if (get_modinfo(info, "livepatch")) {
pr_err("%s: module is marked as livepatch module, but livepatch support is disabled",
@ -2969,7 +2974,7 @@ static int check_modinfo(struct module *mod, struct load_info *info, int flags)
"is unknown, you have been warned.\n", mod->name);
}
err = find_livepatch_modinfo(mod, info);
err = check_modinfo_livepatch(mod, info);
if (err)
return err;