| Message ID | 20241115-sockptr-copy-fixes-v1-0-d183c87fcbd5@rbox.co |
|---|---|
| Headers | show |
| Series | net: Fix some callers of copy_from_sockptr() | expand |
Hi Michal, On Thu, Nov 14, 2024 at 6:33 PM Michal Luczaj <mhal@rbox.co> wrote: > > The bt_copy_from_sockptr() return value is being misinterpreted by most > users: a non-zero result is mistakenly assumed to represent an error code, > but actually indicates the number of bytes that could not be copied. > > Remove bt_copy_from_sockptr() and adapt callers to use > copy_safe_from_sockptr(). > > For sco_sock_setsockopt() (case BT_CODEC) use copy_struct_from_sockptr() to > scrub parts of uninitialized buffer. > > Opportunistically, rename `len` to `optlen` in hci_sock_setsockopt_old() > and hci_sock_setsockopt(). > > Fixes: 51eda36d33e4 ("Bluetooth: SCO: Fix not validating setsockopt user input") > Fixes: a97de7bff13b ("Bluetooth: RFCOMM: Fix not validating setsockopt user input") > Fixes: 4f3951242ace ("Bluetooth: L2CAP: Fix not validating setsockopt user input") > Fixes: 9e8742cdfc4b ("Bluetooth: ISO: Fix not validating setsockopt user input") > Fixes: b2186061d604 ("Bluetooth: hci_sock: Fix not validating setsockopt user input") > Signed-off-by: Michal Luczaj <mhal@rbox.co> Reviewed-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com> > --- > include/net/bluetooth/bluetooth.h | 9 --------- > net/bluetooth/hci_sock.c | 14 +++++++------- > net/bluetooth/iso.c | 10 +++++----- > net/bluetooth/l2cap_sock.c | 20 +++++++++++--------- > net/bluetooth/rfcomm/sock.c | 9 ++++----- > net/bluetooth/sco.c | 11 ++++++----- > 6 files changed, 33 insertions(+), 40 deletions(-) > > diff --git a/include/net/bluetooth/bluetooth.h b/include/net/bluetooth/bluetooth.h > index f66bc85c6411dd5d49eca7756577fea05feaf144..e6760c11f007752ff05792f1de09b70bfb57213c 100644 > --- a/include/net/bluetooth/bluetooth.h > +++ b/include/net/bluetooth/bluetooth.h > @@ -590,15 +590,6 @@ static inline struct sk_buff *bt_skb_sendmmsg(struct sock *sk, > return skb; > } > > -static inline int bt_copy_from_sockptr(void *dst, size_t dst_size, > - sockptr_t src, size_t src_size) > -{ > - if (dst_size > src_size) > - return -EINVAL; > - > - return copy_from_sockptr(dst, src, dst_size); > -} > - > int bt_to_errno(u16 code); > __u8 bt_status(int err); > > diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c > index 2272e1849ebd894a6b83f665d8fa45610778463c..022b86797acdc56a6e9b85f24f4c98a0247831c9 100644 > --- a/net/bluetooth/hci_sock.c > +++ b/net/bluetooth/hci_sock.c > @@ -1926,7 +1926,7 @@ static int hci_sock_sendmsg(struct socket *sock, struct msghdr *msg, > } > > static int hci_sock_setsockopt_old(struct socket *sock, int level, int optname, > - sockptr_t optval, unsigned int len) > + sockptr_t optval, unsigned int optlen) > { > struct hci_ufilter uf = { .opcode = 0 }; > struct sock *sk = sock->sk; > @@ -1943,7 +1943,7 @@ static int hci_sock_setsockopt_old(struct socket *sock, int level, int optname, > > switch (optname) { > case HCI_DATA_DIR: > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, len); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -1954,7 +1954,7 @@ static int hci_sock_setsockopt_old(struct socket *sock, int level, int optname, > break; > > case HCI_TIME_STAMP: > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, len); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -1974,7 +1974,7 @@ static int hci_sock_setsockopt_old(struct socket *sock, int level, int optname, > uf.event_mask[1] = *((u32 *) f->event_mask + 1); > } > > - err = bt_copy_from_sockptr(&uf, sizeof(uf), optval, len); > + err = copy_safe_from_sockptr(&uf, sizeof(uf), optval, optlen); > if (err) > break; > > @@ -2005,7 +2005,7 @@ static int hci_sock_setsockopt_old(struct socket *sock, int level, int optname, > } > > static int hci_sock_setsockopt(struct socket *sock, int level, int optname, > - sockptr_t optval, unsigned int len) > + sockptr_t optval, unsigned int optlen) > { > struct sock *sk = sock->sk; > int err = 0; > @@ -2015,7 +2015,7 @@ static int hci_sock_setsockopt(struct socket *sock, int level, int optname, > > if (level == SOL_HCI) > return hci_sock_setsockopt_old(sock, level, optname, optval, > - len); > + optlen); > > if (level != SOL_BLUETOOTH) > return -ENOPROTOOPT; > @@ -2035,7 +2035,7 @@ static int hci_sock_setsockopt(struct socket *sock, int level, int optname, > goto done; > } > > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, len); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > diff --git a/net/bluetooth/iso.c b/net/bluetooth/iso.c > index 7a83e400ac77a0a0df41b206643bae6fc031631b..5f278971d7fa25b32b6f70a5fc5a7500db0fdc99 100644 > --- a/net/bluetooth/iso.c > +++ b/net/bluetooth/iso.c > @@ -1503,7 +1503,7 @@ static int iso_sock_setsockopt(struct socket *sock, int level, int optname, > break; > } > > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -1514,7 +1514,7 @@ static int iso_sock_setsockopt(struct socket *sock, int level, int optname, > break; > > case BT_PKT_STATUS: > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -1533,7 +1533,7 @@ static int iso_sock_setsockopt(struct socket *sock, int level, int optname, > break; > } > > - err = bt_copy_from_sockptr(&qos, sizeof(qos), optval, optlen); > + err = copy_safe_from_sockptr(&qos, sizeof(qos), optval, optlen); > if (err) > break; > > @@ -1554,8 +1554,8 @@ static int iso_sock_setsockopt(struct socket *sock, int level, int optname, > break; > } > > - err = bt_copy_from_sockptr(iso_pi(sk)->base, optlen, optval, > - optlen); > + err = copy_safe_from_sockptr(iso_pi(sk)->base, optlen, optval, > + optlen); > if (err) > break; > > diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c > index ba437c6f6ee591a5624f5fbfbf28f2a80d399372..5ab203b55ab7e2c0682349a6eab9620e3e8a024c 100644 > --- a/net/bluetooth/l2cap_sock.c > +++ b/net/bluetooth/l2cap_sock.c > @@ -755,7 +755,8 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, > opts.max_tx = chan->max_tx; > opts.txwin_size = chan->tx_win; > > - err = bt_copy_from_sockptr(&opts, sizeof(opts), optval, optlen); > + err = copy_safe_from_sockptr(&opts, sizeof(opts), optval, > + optlen); > if (err) > break; > > @@ -800,7 +801,7 @@ static int l2cap_sock_setsockopt_old(struct socket *sock, int optname, > break; > > case L2CAP_LM: > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -909,7 +910,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, > > sec.level = BT_SECURITY_LOW; > > - err = bt_copy_from_sockptr(&sec, sizeof(sec), optval, optlen); > + err = copy_safe_from_sockptr(&sec, sizeof(sec), optval, optlen); > if (err) > break; > > @@ -956,7 +957,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, > break; > } > > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -970,7 +971,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, > break; > > case BT_FLUSHABLE: > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -1004,7 +1005,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, > > pwr.force_active = BT_POWER_FORCE_ACTIVE_ON; > > - err = bt_copy_from_sockptr(&pwr, sizeof(pwr), optval, optlen); > + err = copy_safe_from_sockptr(&pwr, sizeof(pwr), optval, optlen); > if (err) > break; > > @@ -1015,7 +1016,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, > break; > > case BT_CHANNEL_POLICY: > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -1046,7 +1047,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, > break; > } > > - err = bt_copy_from_sockptr(&mtu, sizeof(mtu), optval, optlen); > + err = copy_safe_from_sockptr(&mtu, sizeof(mtu), optval, optlen); > if (err) > break; > > @@ -1076,7 +1077,8 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, > break; > } > > - err = bt_copy_from_sockptr(&mode, sizeof(mode), optval, optlen); > + err = copy_safe_from_sockptr(&mode, sizeof(mode), optval, > + optlen); > if (err) > break; > > diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c > index f48250e3f2e103c75d5937e1608e43c123aa3297..1001fb4cc21c0ecc7bcdd3ea9041770ede4f27b8 100644 > --- a/net/bluetooth/rfcomm/sock.c > +++ b/net/bluetooth/rfcomm/sock.c > @@ -629,10 +629,9 @@ static int rfcomm_sock_setsockopt_old(struct socket *sock, int optname, > > switch (optname) { > case RFCOMM_LM: > - if (bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen)) { > - err = -EFAULT; > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > + if (err) > break; > - } > > if (opt & RFCOMM_LM_FIPS) { > err = -EINVAL; > @@ -685,7 +684,7 @@ static int rfcomm_sock_setsockopt(struct socket *sock, int level, int optname, > > sec.level = BT_SECURITY_LOW; > > - err = bt_copy_from_sockptr(&sec, sizeof(sec), optval, optlen); > + err = copy_safe_from_sockptr(&sec, sizeof(sec), optval, optlen); > if (err) > break; > > @@ -703,7 +702,7 @@ static int rfcomm_sock_setsockopt(struct socket *sock, int level, int optname, > break; > } > > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > diff --git a/net/bluetooth/sco.c b/net/bluetooth/sco.c > index 1c7252a3686694284b0b1e1101e3d16b90d906c4..700abb639a554521b9b5d46298d5ed926d228470 100644 > --- a/net/bluetooth/sco.c > +++ b/net/bluetooth/sco.c > @@ -853,7 +853,7 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname, > break; > } > > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -872,8 +872,8 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname, > > voice.setting = sco_pi(sk)->setting; > > - err = bt_copy_from_sockptr(&voice, sizeof(voice), optval, > - optlen); > + err = copy_safe_from_sockptr(&voice, sizeof(voice), optval, > + optlen); > if (err) > break; > > @@ -898,7 +898,7 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname, > break; > > case BT_PKT_STATUS: > - err = bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen); > + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); > if (err) > break; > > @@ -941,7 +941,8 @@ static int sco_sock_setsockopt(struct socket *sock, int level, int optname, > break; > } > > - err = bt_copy_from_sockptr(buffer, optlen, optval, optlen); > + err = copy_struct_from_sockptr(buffer, sizeof(buffer), optval, > + optlen); > if (err) { > hci_dev_put(hdev); > break; > > -- > 2.46.2 >
On 2024-11-14 18:50, Luiz Augusto von Dentz wrote: > Hi David, > > On Thu, Nov 14, 2024 at 9:30 PM David Wei <dw@davidwei.uk> wrote: >> >> On 2024-11-14 18:15, Luiz Augusto von Dentz wrote: >>> Hi David, >>> >>> On Thu, Nov 14, 2024 at 7:42 PM David Wei <dw@davidwei.uk> wrote: >>>> >>>> On 2024-11-14 15:27, Michal Luczaj wrote: >>>>> The bt_copy_from_sockptr() return value is being misinterpreted by most >>>>> users: a non-zero result is mistakenly assumed to represent an error code, >>>>> but actually indicates the number of bytes that could not be copied. >>>>> >>>>> Remove bt_copy_from_sockptr() and adapt callers to use >>>>> copy_safe_from_sockptr(). >>>>> >>>>> For sco_sock_setsockopt() (case BT_CODEC) use copy_struct_from_sockptr() to >>>>> scrub parts of uninitialized buffer. >>>>> >>>>> Opportunistically, rename `len` to `optlen` in hci_sock_setsockopt_old() >>>>> and hci_sock_setsockopt(). >>>>> >>>>> Fixes: 51eda36d33e4 ("Bluetooth: SCO: Fix not validating setsockopt user input") >>>>> Fixes: a97de7bff13b ("Bluetooth: RFCOMM: Fix not validating setsockopt user input") >>>>> Fixes: 4f3951242ace ("Bluetooth: L2CAP: Fix not validating setsockopt user input") >>>>> Fixes: 9e8742cdfc4b ("Bluetooth: ISO: Fix not validating setsockopt user input") >>>>> Fixes: b2186061d604 ("Bluetooth: hci_sock: Fix not validating setsockopt user input") >>>>> Signed-off-by: Michal Luczaj <mhal@rbox.co> >>>>> --- >>>>> include/net/bluetooth/bluetooth.h | 9 --------- >>>>> net/bluetooth/hci_sock.c | 14 +++++++------- >>>>> net/bluetooth/iso.c | 10 +++++----- >>>>> net/bluetooth/l2cap_sock.c | 20 +++++++++++--------- >>>>> net/bluetooth/rfcomm/sock.c | 9 ++++----- >>>>> net/bluetooth/sco.c | 11 ++++++----- >>>>> 6 files changed, 33 insertions(+), 40 deletions(-) >>>>> >>>> ... >>>>> diff --git a/net/bluetooth/rfcomm/sock.c b/net/bluetooth/rfcomm/sock.c >>>>> index f48250e3f2e103c75d5937e1608e43c123aa3297..1001fb4cc21c0ecc7bcdd3ea9041770ede4f27b8 100644 >>>>> --- a/net/bluetooth/rfcomm/sock.c >>>>> +++ b/net/bluetooth/rfcomm/sock.c >>>>> @@ -629,10 +629,9 @@ static int rfcomm_sock_setsockopt_old(struct socket *sock, int optname, >>>>> >>>>> switch (optname) { >>>>> case RFCOMM_LM: >>>>> - if (bt_copy_from_sockptr(&opt, sizeof(opt), optval, optlen)) { >>>>> - err = -EFAULT; >>>>> + err = copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen); >>>>> + if (err) >>>>> break; >>>>> - } >>>> >>>> This will return a positive integer if copy_safe_from_sockptr() fails. >>> >>> What are you talking about copy_safe_from_sockptr never returns a >>> positive value: >>> >>> * Returns: >>> * * -EINVAL: @optlen < @ksize >>> * * -EFAULT: access to userspace failed. >>> * * 0 : @ksize bytes were copied >> >> Isn't this what this series is about? copy_from_sockptr() returns 0 on >> success, or a positive integer for number of bytes NOT copied on error. >> Patch 4 even updates the docs for copy_from_sockptr(). >> >> copy_safe_from_sockptr() >> -> copy_from_sockptr() >> -> copy_from_sockptr_offset() >> -> memcpy() for kernel to kernel OR >> -> copy_from_user() otherwise > > Well except the safe version does check what would otherwise cause a > positive return by the likes of copy_from_user and returns -EINVAL > instead, otherwise the documentation of copy_safe_from_sockptr is just > wrong and shall state that it could return positive as well but I > guess that would just make it as inconvenient so we might as well > detect when a positive value would be returned just return -EFAULT > instead. Yes it checks and returns EINVAL, but not EFAULT which is what my comment on the original patch is about. Most of the calls to bt_copy_from_sockptr() that Michal replaced with copy_safe_from_sockptr() remain incorrect because it is assumed that EFAULT is returned. Only rfcomm_sock_setsockopt_old() was vaguely doing the right thing and the patch changed it back to the incorrect pattern: err = copy_safe_from_sockptr(...); if (err) break; But I do agree that making copy_safe_from_sockptr() do the right thing and EFAULT will be easier and prevent future problems given that copy_from_sockptr() is meant to be deprecated anyhow. > >> And copy_from_user() follows the same 0 for success or N > 0 for >> failure. It does not EFAULT on its own AFAIK. >> >> The docs for copy_safe_from_sockptr() that you've linked contains the >> exact misunderstanding that Michal is correcting. >> >>> >>>> Shouldn't this be: >>>> >>>> err = -EFAULT; >>>> if (copy_safe_from_sockptr(&opt, sizeof(opt), optval, optlen)) >>>> break; >>> >>> >>> > > >
On 11/15/24 00:27, Michal Luczaj wrote: > copy_from_sockptr()'s non-zero result represents the number of bytes that > could not be copied. Turn that into EFAULT. > > Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") > Signed-off-by: Michal Luczaj <mhal@rbox.co> > --- > net/llc/af_llc.c | 15 ++++++++------- > 1 file changed, 8 insertions(+), 7 deletions(-) > > diff --git a/net/llc/af_llc.c b/net/llc/af_llc.c > index 4eb52add7103b0f83d6fe7318abf1d1af533d254..c4febedd1ca0e959dcecea524df37eb328bd626d 100644 > --- a/net/llc/af_llc.c > +++ b/net/llc/af_llc.c > @@ -1093,15 +1093,17 @@ static int llc_ui_setsockopt(struct socket *sock, int level, int optname, > struct sock *sk = sock->sk; > struct llc_sock *llc = llc_sk(sk); > unsigned int opt; > - int rc = -EINVAL; > + int rc = 0; > > lock_sock(sk); > - if (unlikely(level != SOL_LLC || optlen != sizeof(int))) > + if (unlikely(level != SOL_LLC || optlen != sizeof(opt))) { > + rc = -EINVAL; > goto out; > - rc = copy_from_sockptr(&opt, optval, sizeof(opt)); > - if (rc) > + } > + if (copy_from_sockptr(&opt, optval, sizeof(opt))) { > + rc = -EFAULT; > goto out; > - rc = -EINVAL; > + } > switch (optname) { > case LLC_OPT_RETRY: > if (opt > LLC_OPT_MAX_RETRY) > @@ -1151,9 +1153,8 @@ static int llc_ui_setsockopt(struct socket *sock, int level, int optname, > break; > default: > rc = -ENOPROTOOPT; > - goto out; > + break; > } > - rc = 0; > out: > release_sock(sk); > return rc; > Great, I broke it in a worse way: on bad input all the checks under the switch would silently fail. Apologies, here is v2: https://lore.kernel.org/netdev/20241115-sockptr-copy-fixes-v2-0-9b1254c18b7a@rbox.co/ Michal PS. Ugh, and I've just realized; sorry for forgetting about the "wait 24h before re-submitting" rule...
Some callers misinterpret copy_from_sockptr()'s return value. The function follows copy_from_user(), i.e. returns 0 for success, or the number of bytes not copied on error. Simply returning the result in a non-zero case isn't usually what was intended. Compile tested with CONFIG_LLC, CONFIG_AF_RXRPC, CONFIG_BT enabled. Last patch probably belongs more to net-next, if any. Here as a RFC. Suggested-by: Jakub Kicinski <kuba@kernel.org> Signed-off-by: Michal Luczaj <mhal@rbox.co> --- Michal Luczaj (4): bluetooth: Improve setsockopt() handling of malformed user input llc: Improve setsockopt() handling of malformed user input rxrpc: Improve setsockopt() handling of malformed user input net: Comment copy_from_sockptr() explaining its behaviour include/linux/sockptr.h | 2 ++ include/net/bluetooth/bluetooth.h | 9 --------- net/bluetooth/hci_sock.c | 14 +++++++------- net/bluetooth/iso.c | 10 +++++----- net/bluetooth/l2cap_sock.c | 20 +++++++++++--------- net/bluetooth/rfcomm/sock.c | 9 ++++----- net/bluetooth/sco.c | 11 ++++++----- net/llc/af_llc.c | 15 ++++++++------- net/rxrpc/af_rxrpc.c | 8 ++++---- 9 files changed, 47 insertions(+), 51 deletions(-) --- base-commit: cfaaa7d010d1fc58f9717fcc8591201e741d2d49 change-id: 20241114-sockptr-copy-fixes-3999eaa81aa1 Best regards,