Messages in this thread | | | Date | Fri, 29 Sep 2023 10:49:45 -0700 | From | Kees Cook <> | Subject | Re: drivers/md/dm-cache-metadata.c:1705:9: warning: 'strncpy' specified bound 16 equals destination size |
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On Thu, Sep 28, 2023 at 11:36:46AM +0200, Miguel Ojeda wrote: > On Thu, Sep 28, 2023 at 12:24 AM kernel test robot <lkp@intel.com> wrote: > > > > In function 'write_hints', > > inlined from 'dm_cache_write_hints' at drivers/md/dm-cache-metadata.c:1729:6: > > >> drivers/md/dm-cache-metadata.c:1705:9: warning: 'strncpy' specified bound 16 equals destination size [-Wstringop-truncation] > > 1705 | strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name)); > > | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > This looks fine given the check above it. In any case, since it > appears the code wants to terminate the string, this should use > `strscpy*()`, right?
I agree. I can't tell if _pad is needed though. I think struct dm_cache_metadata is only used internally? And I see at least the initial allocation is zeroed:
cmd = kzalloc(sizeof(*cmd), GFP_KERNEL);
Regardless, for background,
struct has: char policy_name[CACHE_POLICY_NAME_SIZE];
code does: const char *policy_name = dm_cache_policy_get_name(policy);
if (!policy_name[0] || (strlen(policy_name) > sizeof(cmd->policy_name) - 1)) return -EINVAL;
strncpy(cmd->policy_name, policy_name, sizeof(cmd->policy_name));
Justin, can you add this to your queue (if it's not already there)?
-Kees
-- Kees Cook
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