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charset=us-ascii Content-Disposition: inline In-Reply-To: <20251205161202.48409-1-mikhail.v.gavrilov@gmail.com> X-BeenThere: linux-mediatek@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "Linux-mediatek" Errors-To: linux-mediatek-bounces+linux-mediatek=archiver.kernel.org@lists.infradead.org On Fri, Dec 05, 2025 at 09:12:02PM +0500, Mikhail Gavrilov wrote: > Commit f804a5895eba ("wifi: mt76: Strip whitespace from build ddate") introduced > a kernel panic/WARN on systems using MediaTek MT7921e (and potentially others > using mt76_connac_lib) due to an incorrect buffer size calculation. > > The error logged is: > "strnlen: detected buffer overflow: 17 byte read of buffer size 16" > > This occurs because the field 'hdr->build_date' is a fixed-size array of 16 bytes. > The patch allocated a 17-byte local buffer 'build_date' but used 'sizeof(build_date)' > (17) as the read limit for strscpy, causing Fortify Source to correctly detect > an attempt to read 17 bytes from the 16-byte source field. > > To fix this, replace strscpy with memcpy, which is appropriate for raw data > copying, and explicitly use the size of the source field (sizeof(hdr->build_date) = 16) > to limit the read, followed by manual null termination. > > Fixes: f804a5895eba ("wifi: mt76: Strip whitespace from build ddate") > Signed-off-by: Mikhail Gavrilov > --- > drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c | 7 +++++-- > 1 file changed, 5 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c > index ea99167765b0..d2c4c65ec464 100644 > --- a/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c > +++ b/drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c > @@ -3125,8 +3125,11 @@ int mt76_connac2_load_patch(struct mt76_dev *dev, const char *fw_name) > } > > hdr = (const void *)fw->data; > - strscpy(build_date, hdr->build_date, sizeof(build_date)); > - build_date[16] = '\0'; > + /* hdr->build_date is 16 bytes. Copy exactly 16 bytes to the 17-byte buffer, > + * and then add the null terminator at index 16. > + */ > + memcpy(build_date, hdr->build_date, sizeof(hdr->build_date)); > + build_date[sizeof(hdr->build_date)] = '\0'; > strim(build_date); > dev_info(dev->dev, "HW/SW Version: 0x%x, Build Time: %.16s\n", > be32_to_cpu(hdr->hw_sw_ver), build_date); Tested-by: Eric Biggers Can this be sent upstream soon? - Eric