diff options
| author | Josh Poimboeuf | 2015-01-20 09:26:18 -0600 |
|---|---|---|
| committer | Jiri Kosina | 2015-01-20 20:09:41 +0100 |
| commit | 83a90bb1345767f0cb96d242fd8b9db44b2b0e17 (patch) | |
| tree | 68a4466302071ededbed9c50f4d80e431e656f32 | |
| parent | 32b7eb877165fdb29f1722071c6c64ced1789014 (diff) | |
livepatch: enforce patch stacking semantics
Only allow the topmost patch on the stack to be enabled or disabled, so
that patches can't be removed or added in an arbitrary order.
Suggested-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Reviewed-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
| -rw-r--r-- | kernel/livepatch/core.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c index 3d9c00b5223a..2401e7f955d3 100644 --- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -379,6 +379,11 @@ static int __klp_disable_patch(struct klp_patch *patch) struct klp_object *obj; int ret; + /* enforce stacking: only the last enabled patch can be disabled */ + if (!list_is_last(&patch->list, &klp_patches) && + list_next_entry(patch, list)->state == KLP_ENABLED) + return -EBUSY; + pr_notice("disabling patch '%s'\n", patch->mod->name); for (obj = patch->objs; obj->funcs; obj++) { @@ -435,6 +440,11 @@ static int __klp_enable_patch(struct klp_patch *patch) if (WARN_ON(patch->state != KLP_DISABLED)) return -EINVAL; + /* enforce stacking: only the first disabled patch can be enabled */ + if (patch->list.prev != &klp_patches && + 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); |