4.18-stable review patch. If anyone has any objections, please let me know.
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From: Kamalesh Babulal kamalesh@linux.vnet.ibm.com
commit 6e9df95b76cad18f7b217bdad7bb8a26d63b8c47 upstream.
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.
Cc: stable@vger.kernel.org Signed-off-by: Kamalesh Babulal kamalesh@linux.vnet.ibm.com Acked-by: Josh Poimboeuf jpoimboe@redhat.com Signed-off-by: Jiri Kosina jkosina@suse.cz Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- kernel/livepatch/core.c | 6 ++++++ 1 file changed, 6 insertions(+)
--- a/kernel/livepatch/core.c +++ b/kernel/livepatch/core.c @@ -678,6 +678,9 @@ static int klp_init_func(struct klp_obje if (!func->old_name || !func->new_func) return -EINVAL;
+ if (strlen(func->old_name) >= KSYM_NAME_LEN) + return -EINVAL; + INIT_LIST_HEAD(&func->stack_node); func->patched = false; func->transition = false; @@ -751,6 +754,9 @@ static int klp_init_object(struct klp_pa if (!obj->funcs) return -EINVAL;
+ if (klp_is_module(obj) && strlen(obj->name) >= MODULE_NAME_LEN) + return -EINVAL; + obj->patched = false; obj->mod = NULL;