| Message ID | 20221024162843.535921-1-Jason@zx2c4.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | e6cb8769452e8236b52134e5cb4a18b8f5986932 |
| Delegated to: | Kalle Valo |
| Headers | show |
| Series | wifi: cisco: do not assign -1 to unsigned char | expand |
From: Jason A. Donenfeld > Sent: 24 October 2022 17:29 > > With char becoming unsigned by default, and with `char` alone being > ambiguous and based on architecture, we get a warning when assigning the > unchecked output of hex_to_bin() to that unsigned char. Mark `key` as a > `u8`, which matches the struct's type, and then check each call to > hex_to_bin() before casting. > > Cc: Kalle Valo <kvalo@kernel.org> > Cc: linux-wireless@vger.kernel.org > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > --- > drivers/net/wireless/cisco/airo.c | 18 ++++++++++++++---- > 1 file changed, 14 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c > index 10daef81c355..fb2c35bd73bb 100644 > --- a/drivers/net/wireless/cisco/airo.c > +++ b/drivers/net/wireless/cisco/airo.c > @@ -5232,7 +5232,7 @@ static int get_wep_tx_idx(struct airo_info *ai) > return -1; > } > > -static int set_wep_key(struct airo_info *ai, u16 index, const char *key, > +static int set_wep_key(struct airo_info *ai, u16 index, const u8 *key, > u16 keylen, int perm, int lock) > { > static const unsigned char macaddr[ETH_ALEN] = { 0x01, 0, 0, 0, 0, 0 }; > @@ -5283,7 +5283,7 @@ static void proc_wepkey_on_close(struct inode *inode, struct file *file) > struct net_device *dev = pde_data(inode); > struct airo_info *ai = dev->ml_priv; > int i, rc; > - char key[16]; > + u8 key[16]; > u16 index = 0; > int j = 0; > > @@ -5311,12 +5311,22 @@ static void proc_wepkey_on_close(struct inode *inode, struct file *file) > } > > for (i = 0; i < 16*3 && data->wbuffer[i+j]; i++) { > + int val; > + > + if (i % 3 == 2) > + continue; > + > + val = hex_to_bin(data->wbuffer[i+j]); > + if (val < 0) { > + airo_print_err(ai->dev->name, "WebKey passed invalid key hex"); > + return; > + } > switch(i%3) { > case 0: > - key[i/3] = hex_to_bin(data->wbuffer[i+j])<<4; > + key[i/3] = (u8)val << 4; > break; > case 1: > - key[i/3] |= hex_to_bin(data->wbuffer[i+j]); > + key[i/3] |= (u8)val; > break; > } > } That is about the crappiest loop I've seen. I was just going to point out that the (u8) casts aren't needed. Something like: for (i = 0, buf = data->wbuffer + j; i < 16; i++, buf += 3) { int val; if (!buf[0] || !buf[1]) break; val = hex_to_bin(buf[0]) | hex_to_bin(buf[1]) << 8; if (val < 0) { airo_print_err(ai->dev->name, "WebKey passed invalid key hex"); return; } key[i] = val; if (!buf[2]) break; } Although there should be a check for buf[2] being valid. Any I worry about exactly what happens if there aren't 16 full bytes. David - Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK Registration No: 1397386 (Wales)
On Tue, Oct 25, 2022 at 10:11:44AM +0000, David Laight wrote: > From: Jason A. Donenfeld > > Sent: 24 October 2022 17:29 > > > > With char becoming unsigned by default, and with `char` alone being > > ambiguous and based on architecture, we get a warning when assigning the > > unchecked output of hex_to_bin() to that unsigned char. Mark `key` as a > > `u8`, which matches the struct's type, and then check each call to > > hex_to_bin() before casting. > > > > Cc: Kalle Valo <kvalo@kernel.org> > > Cc: linux-wireless@vger.kernel.org > > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> > > --- > > drivers/net/wireless/cisco/airo.c | 18 ++++++++++++++---- > > 1 file changed, 14 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c > > index 10daef81c355..fb2c35bd73bb 100644 > > --- a/drivers/net/wireless/cisco/airo.c > > +++ b/drivers/net/wireless/cisco/airo.c > > @@ -5232,7 +5232,7 @@ static int get_wep_tx_idx(struct airo_info *ai) > > return -1; > > } > > > > -static int set_wep_key(struct airo_info *ai, u16 index, const char *key, > > +static int set_wep_key(struct airo_info *ai, u16 index, const u8 *key, > > u16 keylen, int perm, int lock) > > { > > static const unsigned char macaddr[ETH_ALEN] = { 0x01, 0, 0, 0, 0, 0 }; > > @@ -5283,7 +5283,7 @@ static void proc_wepkey_on_close(struct inode *inode, struct file *file) > > struct net_device *dev = pde_data(inode); > > struct airo_info *ai = dev->ml_priv; > > int i, rc; > > - char key[16]; > > + u8 key[16]; > > u16 index = 0; > > int j = 0; > > > > @@ -5311,12 +5311,22 @@ static void proc_wepkey_on_close(struct inode *inode, struct file *file) > > } > > > > for (i = 0; i < 16*3 && data->wbuffer[i+j]; i++) { > > + int val; > > + > > + if (i % 3 == 2) > > + continue; > > + > > + val = hex_to_bin(data->wbuffer[i+j]); > > + if (val < 0) { > > + airo_print_err(ai->dev->name, "WebKey passed invalid key hex"); > > + return; > > + } > > switch(i%3) { > > case 0: > > - key[i/3] = hex_to_bin(data->wbuffer[i+j])<<4; > > + key[i/3] = (u8)val << 4; > > break; > > case 1: > > - key[i/3] |= hex_to_bin(data->wbuffer[i+j]); > > + key[i/3] |= (u8)val; > > break; > > } > > } > > That is about the crappiest loop I've seen. > I was just going to point out that the (u8) casts aren't needed. > Something like: > for (i = 0, buf = data->wbuffer + j; i < 16; i++, buf += 3) { > int val; > if (!buf[0] || !buf[1]) > break; > val = hex_to_bin(buf[0]) | hex_to_bin(buf[1]) << 8; > if (val < 0) { > airo_print_err(ai->dev->name, "WebKey passed invalid key hex"); > return; > } > key[i] = val; > if (!buf[2]) > break; > } > > Although there should be a check for buf[2] being valid. > Any I worry about exactly what happens if there aren't 16 full bytes. buf[2] isn't checked. Presumably it's a space or something. Your <<8 also isn't right; this is a hex char. Anyway, I think I'd rather minimize this delta and leave this patch as-is. Jason
"Jason A. Donenfeld" <Jason@zx2c4.com> wrote: > With char becoming unsigned by default, and with `char` alone being > ambiguous and based on architecture, we get a warning when assigning the > unchecked output of hex_to_bin() to that unsigned char. Mark `key` as a > `u8`, which matches the struct's type, and then check each call to > hex_to_bin() before casting. > > Cc: Kalle Valo <kvalo@kernel.org> > Cc: linux-wireless@vger.kernel.org > Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> Patch applied to wireless.git, thanks. e6cb8769452e wifi: airo: do not assign -1 to unsigned char
diff --git a/drivers/net/wireless/cisco/airo.c b/drivers/net/wireless/cisco/airo.c index 10daef81c355..fb2c35bd73bb 100644 --- a/drivers/net/wireless/cisco/airo.c +++ b/drivers/net/wireless/cisco/airo.c @@ -5232,7 +5232,7 @@ static int get_wep_tx_idx(struct airo_info *ai) return -1; } -static int set_wep_key(struct airo_info *ai, u16 index, const char *key, +static int set_wep_key(struct airo_info *ai, u16 index, const u8 *key, u16 keylen, int perm, int lock) { static const unsigned char macaddr[ETH_ALEN] = { 0x01, 0, 0, 0, 0, 0 }; @@ -5283,7 +5283,7 @@ static void proc_wepkey_on_close(struct inode *inode, struct file *file) struct net_device *dev = pde_data(inode); struct airo_info *ai = dev->ml_priv; int i, rc; - char key[16]; + u8 key[16]; u16 index = 0; int j = 0; @@ -5311,12 +5311,22 @@ static void proc_wepkey_on_close(struct inode *inode, struct file *file) } for (i = 0; i < 16*3 && data->wbuffer[i+j]; i++) { + int val; + + if (i % 3 == 2) + continue; + + val = hex_to_bin(data->wbuffer[i+j]); + if (val < 0) { + airo_print_err(ai->dev->name, "WebKey passed invalid key hex"); + return; + } switch(i%3) { case 0: - key[i/3] = hex_to_bin(data->wbuffer[i+j])<<4; + key[i/3] = (u8)val << 4; break; case 1: - key[i/3] |= hex_to_bin(data->wbuffer[i+j]); + key[i/3] |= (u8)val; break; } }
With char becoming unsigned by default, and with `char` alone being ambiguous and based on architecture, we get a warning when assigning the unchecked output of hex_to_bin() to that unsigned char. Mark `key` as a `u8`, which matches the struct's type, and then check each call to hex_to_bin() before casting. Cc: Kalle Valo <kvalo@kernel.org> Cc: linux-wireless@vger.kernel.org Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com> --- drivers/net/wireless/cisco/airo.c | 18 ++++++++++++++---- 1 file changed, 14 insertions(+), 4 deletions(-)