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Subject[PATCH] livepatch: Validate module/old func name length
livepatch module author can pass module name/old function name with more
than the defined character limit. With obj->name length greater than
MODULE_NAME_LEN, the livepatch module gets loaded but waits forever on
the module specified by obj->name to be loaded. It also populates a /sys
directory with an untruncated object name.

In the case of funcs->old_name length greater then KSYM_NAME_LEN, it
would not match against any of the symbol table entries. Instead loop
through the symbol table comparing them against a nonexisting function,
which can be avoided.

The same issues apply, to misspelled/incorrect names. At least gatekeep
the modules with over the limit string length, by checking for their
length during livepatch module registration.

Signed-off-by: Kamalesh Babulal <>
kernel/livepatch/core.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/kernel/livepatch/core.c b/kernel/livepatch/core.c
index 3a4656fb7047..5b77a7314e01 100644
--- a/kernel/livepatch/core.c
+++ b/kernel/livepatch/core.c
@@ -678,6 +678,9 @@ static int klp_init_func(struct klp_object *obj, struct klp_func *func)
if (!func->old_name || !func->new_func)
return -EINVAL;

+ if (strlen(func->old_name) >= KSYM_NAME_LEN)
+ return -EINVAL;
func->patched = false;
func->transition = false;
@@ -751,6 +754,9 @@ static int klp_init_object(struct klp_patch *patch, struct klp_object *obj)
if (!obj->funcs)
return -EINVAL;

+ if (klp_is_module(obj) && strlen(obj->name) >= MODULE_NAME_LEN)
+ return -EINVAL;
obj->patched = false;
obj->mod = NULL;

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