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livepatch: Validate module/old func name length

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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>
This commit is contained in:
Kamalesh Babulal 2018-07-20 15:16:42 +05:30 committed by Jiri Kosina
parent a48c7709fe
commit 6e9df95b76
1 changed files with 6 additions and 0 deletions
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6
kernel/livepatch/core.c
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@ -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;
INIT_LIST_HEAD(&func->stack_node);
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;