diff options
| author | Justin Stitt <justinstitt@google.com> | 2023-10-03 21:01:58 +0000 |
|---|---|---|
| committer | Kees Cook <keescook@chromium.org> | 2023-11-30 13:38:50 -0800 |
| commit | d4011f6817ae85e42874af705fec866fec7c4ecf (patch) | |
| tree | 3ffa2ac9dfa3abc5bdb23cb77e85329b6249980e /drivers/hid | |
| parent | 40b2519d7566266d7eafd3c5232c73a497640bca (diff) | |
| download | linux-d4011f6817ae85e42874af705fec866fec7c4ecf.tar.gz | |
HID: uhid: replace deprecated strncpy with strscpy
`strncpy` is deprecated for use on NUL-terminated destination strings
[1] and as such we should prefer more robust and less ambiguous string
interfaces.
A suitable replacement is `strscpy` [2] due to the fact that it
guarantees NUL-termination on the destination buffer without
unnecessarily NUL-padding.
Furthermore, let's make sure `hid->xyz` and `ev->u.create2.xyz` are the
same size at compile time to prevent silent truncation.
With these changes, it is abundantly clear what the intent and behavior
of the code is -- We are getting a string to string copy with
NUL-termination and no truncation.
Link: https://www.kernel.org/doc/html/latest/process/deprecated.html#strncpy-on-nul-terminated-strings [1]
Link: https://manpages.debian.org/testing/linux-manual-4.8/strscpy.9.en.html [2]
Link: https://github.com/KSPP/linux/issues/90
Cc: linux-hardening@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Link: https://lore.kernel.org/r/20231003-strncpy-drivers-hid-uhid-c-v2-1-6a501402581e@google.com
Signed-off-by: Kees Cook <keescook@chromium.org>
Diffstat (limited to 'drivers/hid')
| -rw-r--r-- | drivers/hid/uhid.c | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/drivers/hid/uhid.c b/drivers/hid/uhid.c index 4588d2cd4ea44..a54c7995b9be0 100644 --- a/drivers/hid/uhid.c +++ b/drivers/hid/uhid.c @@ -490,7 +490,7 @@ static int uhid_dev_create2(struct uhid_device *uhid, const struct uhid_event *ev) { struct hid_device *hid; - size_t rd_size, len; + size_t rd_size; void *rd_data; int ret; @@ -514,13 +514,12 @@ static int uhid_dev_create2(struct uhid_device *uhid, goto err_free; } - /* @hid is zero-initialized, strncpy() is correct, strlcpy() not */ - len = min(sizeof(hid->name), sizeof(ev->u.create2.name)) - 1; - strncpy(hid->name, ev->u.create2.name, len); - len = min(sizeof(hid->phys), sizeof(ev->u.create2.phys)) - 1; - strncpy(hid->phys, ev->u.create2.phys, len); - len = min(sizeof(hid->uniq), sizeof(ev->u.create2.uniq)) - 1; - strncpy(hid->uniq, ev->u.create2.uniq, len); + BUILD_BUG_ON(sizeof(hid->name) != sizeof(ev->u.create2.name)); + strscpy(hid->name, ev->u.create2.name, sizeof(hid->name)); + BUILD_BUG_ON(sizeof(hid->phys) != sizeof(ev->u.create2.phys)); + strscpy(hid->phys, ev->u.create2.phys, sizeof(hid->phys)); + BUILD_BUG_ON(sizeof(hid->uniq) != sizeof(ev->u.create2.uniq)); + strscpy(hid->uniq, ev->u.create2.uniq, sizeof(hid->uniq)); hid->ll_driver = &uhid_hid_driver; hid->bus = ev->u.create2.bus; |