On Tue, Jan 25, 2022 at 12:50:46AM +0800, Zhou Qingyang wrote:
> In brcmf_of_probe(), the return value of devm_kzalloc() is assigned to
> board_type and there is a dereference of it in strcpy() right after
> that. devm_kzalloc() could return NULL on failure of allocation, which
> could lead to NULL pointer dereference.
>
> Fix this bug by adding a NULL check of board_type.
>
> This bug was found by a static analyzer.
>
> Builds with 'make allyesconfig' show no new warnings,
> and our static analyzer no longer warns about this code
>
> Fixes: 29e354ebeeec ("brcmfmac: Transform compatible string for FW loading")
> Signed-off-by: Zhou Qingyang <zhou1615@xxxxxxx>
> ---
> The analysis employs differential checking to identify inconsistent
> security operations (e.g., checks or kfrees) between two code paths
> and confirms that the inconsistent operations are not recovered in the
> current function or the callers, so they constitute bugs.
>
> Note that, as a bug found by static analysis, it can be a false
> positive or hard to trigger. Multiple researchers have cross-reviewed
> the bug.
>
> drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> index 513c7e6421b2..535e8ddeab8d 100644
> --- a/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> +++ b/drivers/net/wireless/broadcom/brcm80211/brcmfmac/of.c
> @@ -80,6 +80,8 @@ void brcmf_of_probe(struct device *dev, enum brcmf_bus_type bus_type,
> /* get rid of '/' in the compatible string to be able to find the FW */
> len = strlen(tmp) + 1;
> board_type = devm_kzalloc(dev, len, GFP_KERNEL);
> + if (!board_type)
> + return;
> strscpy(board_type, tmp, len);
> for (i = 0; i < board_type[i]; i++) {
> if (board_type[i] == '/')
> --
> 2.25.1
>
As stated before, umn.edu is still not allowed to contribute to the
Linux kernel. Please work with your administration to resolve this
issue.
