On Tue, 9 Jun 2026 15:39:35 +0200 Paolo Abeni <[email protected]> wrote:
> On 6/8/26 11:54 AM, [email protected] wrote: > > From: David Laight <[email protected]> > > > > Replacing strcpy() with strscpy() ensures that overflow of the target > > buffer cannot happen. > > > > Signed-off-by: David Laight <[email protected]> > > --- > > This is one of a group of patches that remove potentially unbounded > > strcpy() calls. > > > > They are mostly replaced by strscpy() or, when strlen() has just been > > called, with memcpy() (usually including the '\0'). > > > > Calls with copy string literals into arrays are left unchanged. > > They are safe and easily detected as such. > > > > The changes were made by getting the compiler to detect the calls and > > then fixing the code by hand. > > > > Note that all the changes are only compile tested. > > > > Some Makefiles were changed to allow files to contain strcpy(). > > As well as 'difficult to fix' files, this included 'show' functions > > as they really need to use sysfs_emit() or seq_printf(). > > > > All the patches are being sent individually to avoid very long cc lists. > > Apologies for the terse commit messages and likely unexpected tags. > > (There are about 100 patches in total.) > > > > net/devlink/port.c | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/net/devlink/port.c b/net/devlink/port.c > > index 485029d43428..108926d3f899 100644 > > --- a/net/devlink/port.c > > +++ b/net/devlink/port.c > > @@ -1222,7 +1222,7 @@ static void __devlink_port_type_set(struct > > devlink_port *devlink_port, > > devlink_port->type_eth.ifindex = netdev->ifindex; > > BUILD_BUG_ON(sizeof(devlink_port->type_eth.ifname) != > > sizeof(netdev->name)); > > - strcpy(devlink_port->type_eth.ifname, netdev->name); > > + strscpy(devlink_port->type_eth.ifname, netdev->name); > > Given the above BUILD_BUG, I don't see how this change can help?!? > > Generally speaking, I suggest restricting this kind of tool-assisted > changes to real problems (if any). My aim is to get to the point where the calling strcpy() is invalid unless it is used to copy a string literal into an array. If/when all the .c files are changed the .h file change can be committed to stop any new potential unbounded copies being added. I do want to look at the 'fortify' version of strspcy(). The current version can call strnlen() and then real_strscpy(), so ends up doing the length scan twice. (Never mind how much gets inlined.) strscpy() between arrays could be implemented as a memcpy() of the shorter length and an explicit zero of the final byte. With the BUILD_BUG_ON() (which I didn't notice) the above could be e memcpy(). -- David > > Thanks, > > Paolo >
