9d0d0a2070
Let's move away from using strncpy and instead favor a less ambiguous
and more robust interface.
For ifp->ndev->name, we expect ifp->ndev->name to be NUL-terminated based
on its use in format strings within core.c:
67 | char *brcmf_ifname(struct brcmf_if *ifp)
68 | {
69 | if (!ifp)
70 | return "<if_null>";
71 |
72 | if (ifp->ndev)
73 | return ifp->ndev->name;
74 |
75 | return "<if_none>";
76 | }
...
288 | static netdev_tx_t brcmf_netdev_start_xmit(struct sk_buff *skb,
289 | struct net_device *ndev) {
...
330 | brcmf_dbg(INFO, "%s: insufficient headroom (%d)\n",
331 | brcmf_ifname(ifp), head_delta);
...
336 | bphy_err(drvr, "%s: failed to expand headroom\n",
337 | brcmf_ifname(ifp));
For di->name, we expect di->name to be NUL-terminated based on its usage
with format strings:
| brcms_dbg_dma(di->core,
| "%s: DMA64 tx doesn't have AE set\n",
| di->name);
Looking at its allocation we can see that it is already zero-allocated
which means NUL-padding is not required:
| di = kzalloc(sizeof(struct dma_info), GFP_ATOMIC);
For wlc->modulecb[i].name, we expect each name in wlc->modulecb to be
NUL-terminated based on their usage with strcmp():
| if (!strcmp(wlc->modulecb[i].name, name) &&
NUL-padding is not required as wlc is zero-allocated in:
brcms_c_attach_malloc() ->
| wlc = kzalloc(sizeof(struct brcms_c_info), GFP_ATOMIC);
For all these cases, a suitable replacement is `strscpy` due to the fact
that it guarantees NUL-termination on the destination buffer without
unnecessarily NUL-padding.
Signed-off-by: Justin Stitt <justinstitt@google.com>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231017-strncpy-drivers-net-wireless-broadcom-brcm80211-brcmfmac-cfg80211-c-v3-1-af780d74ae38@google.com
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.