* [PATCH] riscv: Return -EFAULT if copy_to_user() failed in signal.c @ 2021-03-02 7:28 ` Tiezhu Yang 0 siblings, 0 replies; 6+ messages in thread From: Tiezhu Yang @ 2021-03-02 7:28 UTC (permalink / raw) To: Paul Walmsley, Palmer Dabbelt, Albert Ou; +Cc: linux-riscv, linux-kernel copy_to_user() returns the amount left to copy, it should return -EFAULT if copy to user failed. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> --- arch/riscv/kernel/signal.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 65942b3..2238fc5 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -67,7 +67,7 @@ static long save_fp_state(struct pt_regs *regs, fstate_save(current, regs); err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); if (unlikely(err)) - return err; + return -EFAULT; /* We support no other extension state at this time. */ for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { @@ -140,8 +140,12 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, { struct sigcontext __user *sc = &frame->uc.uc_mcontext; long err; + /* sc_regs is structured the same as the start of pt_regs */ err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); + if (unlikely(err)) + return -EFAULT; + /* Save the floating-point state. */ if (has_fpu) err |= save_fp_state(regs, &sc->sc_fpregs); -- 2.1.0 ^ permalink raw reply related [flat|nested] 6+ messages in thread
* [PATCH] riscv: Return -EFAULT if copy_to_user() failed in signal.c @ 2021-03-02 7:28 ` Tiezhu Yang 0 siblings, 0 replies; 6+ messages in thread From: Tiezhu Yang @ 2021-03-02 7:28 UTC (permalink / raw) To: Paul Walmsley, Palmer Dabbelt, Albert Ou; +Cc: linux-riscv, linux-kernel copy_to_user() returns the amount left to copy, it should return -EFAULT if copy to user failed. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> --- arch/riscv/kernel/signal.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 65942b3..2238fc5 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -67,7 +67,7 @@ static long save_fp_state(struct pt_regs *regs, fstate_save(current, regs); err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); if (unlikely(err)) - return err; + return -EFAULT; /* We support no other extension state at this time. */ for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { @@ -140,8 +140,12 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, { struct sigcontext __user *sc = &frame->uc.uc_mcontext; long err; + /* sc_regs is structured the same as the start of pt_regs */ err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); + if (unlikely(err)) + return -EFAULT; + /* Save the floating-point state. */ if (has_fpu) err |= save_fp_state(regs, &sc->sc_fpregs); -- 2.1.0 _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] riscv: Return -EFAULT if copy_to_user() failed in signal.c 2021-03-02 7:28 ` Tiezhu Yang @ 2021-03-02 10:01 ` Ben Dooks -1 siblings, 0 replies; 6+ messages in thread From: Ben Dooks @ 2021-03-02 10:01 UTC (permalink / raw) To: Tiezhu Yang, Paul Walmsley, Palmer Dabbelt, Albert Ou Cc: linux-riscv, linux-kernel On 02/03/2021 07:28, Tiezhu Yang wrote: > copy_to_user() returns the amount left to copy, it should return -EFAULT > if copy to user failed. This looks technically correct, but the caller (only one) will check for non-zero and will covert that to -EFAULT in setup_rt_frame(). I expect if this change is done, it also needs to be done for the callers too and there's a few others than assume !=0 is an error. I think it would be easier to define save_fp_state() to return non-zero on error and note it does not return an error code. It may be worth exiting the functio nif the first __copy_to_user fails? Note: setup_rt_frame -> setup_sigcontext -> save_fp_frame > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > --- > arch/riscv/kernel/signal.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c > index 65942b3..2238fc5 100644 > --- a/arch/riscv/kernel/signal.c > +++ b/arch/riscv/kernel/signal.c > @@ -67,7 +67,7 @@ static long save_fp_state(struct pt_regs *regs, > fstate_save(current, regs); > err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); > if (unlikely(err)) > - return err; > + return -EFAULT; > > /* We support no other extension state at this time. */ > for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { > @@ -140,8 +140,12 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, > { > struct sigcontext __user *sc = &frame->uc.uc_mcontext; > long err; > + > /* sc_regs is structured the same as the start of pt_regs */ > err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); > + if (unlikely(err)) > + return -EFAULT; > + > /* Save the floating-point state. */ > if (has_fpu) > err |= save_fp_state(regs, &sc->sc_fpregs); > -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius https://www.codethink.co.uk/privacy.html ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] riscv: Return -EFAULT if copy_to_user() failed in signal.c @ 2021-03-02 10:01 ` Ben Dooks 0 siblings, 0 replies; 6+ messages in thread From: Ben Dooks @ 2021-03-02 10:01 UTC (permalink / raw) To: Tiezhu Yang, Paul Walmsley, Palmer Dabbelt, Albert Ou Cc: linux-riscv, linux-kernel On 02/03/2021 07:28, Tiezhu Yang wrote: > copy_to_user() returns the amount left to copy, it should return -EFAULT > if copy to user failed. This looks technically correct, but the caller (only one) will check for non-zero and will covert that to -EFAULT in setup_rt_frame(). I expect if this change is done, it also needs to be done for the callers too and there's a few others than assume !=0 is an error. I think it would be easier to define save_fp_state() to return non-zero on error and note it does not return an error code. It may be worth exiting the functio nif the first __copy_to_user fails? Note: setup_rt_frame -> setup_sigcontext -> save_fp_frame > > Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> > --- > arch/riscv/kernel/signal.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c > index 65942b3..2238fc5 100644 > --- a/arch/riscv/kernel/signal.c > +++ b/arch/riscv/kernel/signal.c > @@ -67,7 +67,7 @@ static long save_fp_state(struct pt_regs *regs, > fstate_save(current, regs); > err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); > if (unlikely(err)) > - return err; > + return -EFAULT; > > /* We support no other extension state at this time. */ > for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { > @@ -140,8 +140,12 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, > { > struct sigcontext __user *sc = &frame->uc.uc_mcontext; > long err; > + > /* sc_regs is structured the same as the start of pt_regs */ > err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); > + if (unlikely(err)) > + return -EFAULT; > + > /* Save the floating-point state. */ > if (has_fpu) > err |= save_fp_state(regs, &sc->sc_fpregs); > -- Ben Dooks http://www.codethink.co.uk/ Senior Engineer Codethink - Providing Genius https://www.codethink.co.uk/privacy.html _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv ^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] riscv: Return -EFAULT if copy_to_user() failed in signal.c 2021-03-02 10:01 ` Ben Dooks @ 2021-03-03 1:53 ` Tiezhu Yang -1 siblings, 0 replies; 6+ messages in thread From: Tiezhu Yang @ 2021-03-03 1:53 UTC (permalink / raw) To: Ben Dooks, Paul Walmsley, Palmer Dabbelt, Albert Ou Cc: linux-riscv, linux-kernel On 03/02/2021 06:01 PM, Ben Dooks wrote: > On 02/03/2021 07:28, Tiezhu Yang wrote: >> copy_to_user() returns the amount left to copy, it should return -EFAULT >> if copy to user failed. > > This looks technically correct, but the caller (only one) > will check for non-zero and will covert that to -EFAULT > in setup_rt_frame(). Yes, as you said, the original code logic has no problem, it will covert that to -EFAULT in setup_rt_frame(). The initial aim of this patch is to make save_fp_state() return error code if __copy_to_user() failed, just like it returns -EFAULT if __put_user() failed. I notice that restore_fp_state() has similar issue, it will return -EFAULT if __get_user() failed and maybe return -EINVAL in the other error case, both -EFAULT and -EINVAL are error code, but when __copy_from_user() failed, it does not return an error code, which seems not so consistent. > > I expect if this change is done, it also needs to be done > for the callers too and there's a few others than assume > !=0 is an error. > > I think it would be easier to define save_fp_state() to > return non-zero on error and note it does not return an > error code. It may be worth exiting the functio nif > the first __copy_to_user fails? Now, (1) is it necessary to do some changes? If yes, I will send v2 later. Like this: [PATCH v2] riscv: Return -EFAULT if copy_{to,from}_user() failed in signal.c copy_{to,from}_user() returns the amount left to copy, it should return -EFAULT error code if copy {to,from} user failed, just like the return value is an error code when {put,get}_user() failed, this is to make the return value consistent, no function change. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> --- arch/riscv/kernel/signal.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 65942b3..c76d877 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -39,7 +39,7 @@ static long restore_fp_state(struct pt_regs *regs, err = __copy_from_user(¤t->thread.fstate, state, sizeof(*state)); if (unlikely(err)) - return err; + return -EFAULT; fstate_restore(current, regs); @@ -67,7 +67,7 @@ static long save_fp_state(struct pt_regs *regs, fstate_save(current, regs); err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); if (unlikely(err)) - return err; + return -EFAULT; /* We support no other extension state at this time. */ for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { @@ -87,8 +87,12 @@ static long restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { long err; + /* sc_regs is structured the same as the start of pt_regs */ err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs)); + if (unlikely(err)) + return -EFAULT; + /* Restore the floating-point state. */ if (has_fpu) err |= restore_fp_state(regs, &sc->sc_fpregs); @@ -140,8 +144,12 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, { struct sigcontext __user *sc = &frame->uc.uc_mcontext; long err; + /* sc_regs is structured the same as the start of pt_regs */ err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); + if (unlikely(err)) + return -EFAULT; + /* Save the floating-point state. */ if (has_fpu) err |= save_fp_state(regs, &sc->sc_fpregs); -- 2.1.0 (2) or just leave it as it is and ignore this patch? Thanks, Tiezhu > > Note: setup_rt_frame -> setup_sigcontext -> save_fp_frame > >> >> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> >> --- >> arch/riscv/kernel/signal.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c >> index 65942b3..2238fc5 100644 >> --- a/arch/riscv/kernel/signal.c >> +++ b/arch/riscv/kernel/signal.c >> @@ -67,7 +67,7 @@ static long save_fp_state(struct pt_regs *regs, >> fstate_save(current, regs); >> err = __copy_to_user(state, ¤t->thread.fstate, >> sizeof(*state)); >> if (unlikely(err)) >> - return err; >> + return -EFAULT; >> /* We support no other extension state at this time. */ >> for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { >> @@ -140,8 +140,12 @@ static long setup_sigcontext(struct rt_sigframe >> __user *frame, >> { >> struct sigcontext __user *sc = &frame->uc.uc_mcontext; >> long err; >> + >> /* sc_regs is structured the same as the start of pt_regs */ >> err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); >> + if (unlikely(err)) >> + return -EFAULT; >> + >> /* Save the floating-point state. */ >> if (has_fpu) >> err |= save_fp_state(regs, &sc->sc_fpregs); >> > > ^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] riscv: Return -EFAULT if copy_to_user() failed in signal.c @ 2021-03-03 1:53 ` Tiezhu Yang 0 siblings, 0 replies; 6+ messages in thread From: Tiezhu Yang @ 2021-03-03 1:53 UTC (permalink / raw) To: Ben Dooks, Paul Walmsley, Palmer Dabbelt, Albert Ou Cc: linux-riscv, linux-kernel On 03/02/2021 06:01 PM, Ben Dooks wrote: > On 02/03/2021 07:28, Tiezhu Yang wrote: >> copy_to_user() returns the amount left to copy, it should return -EFAULT >> if copy to user failed. > > This looks technically correct, but the caller (only one) > will check for non-zero and will covert that to -EFAULT > in setup_rt_frame(). Yes, as you said, the original code logic has no problem, it will covert that to -EFAULT in setup_rt_frame(). The initial aim of this patch is to make save_fp_state() return error code if __copy_to_user() failed, just like it returns -EFAULT if __put_user() failed. I notice that restore_fp_state() has similar issue, it will return -EFAULT if __get_user() failed and maybe return -EINVAL in the other error case, both -EFAULT and -EINVAL are error code, but when __copy_from_user() failed, it does not return an error code, which seems not so consistent. > > I expect if this change is done, it also needs to be done > for the callers too and there's a few others than assume > !=0 is an error. > > I think it would be easier to define save_fp_state() to > return non-zero on error and note it does not return an > error code. It may be worth exiting the functio nif > the first __copy_to_user fails? Now, (1) is it necessary to do some changes? If yes, I will send v2 later. Like this: [PATCH v2] riscv: Return -EFAULT if copy_{to,from}_user() failed in signal.c copy_{to,from}_user() returns the amount left to copy, it should return -EFAULT error code if copy {to,from} user failed, just like the return value is an error code when {put,get}_user() failed, this is to make the return value consistent, no function change. Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> --- arch/riscv/kernel/signal.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c index 65942b3..c76d877 100644 --- a/arch/riscv/kernel/signal.c +++ b/arch/riscv/kernel/signal.c @@ -39,7 +39,7 @@ static long restore_fp_state(struct pt_regs *regs, err = __copy_from_user(¤t->thread.fstate, state, sizeof(*state)); if (unlikely(err)) - return err; + return -EFAULT; fstate_restore(current, regs); @@ -67,7 +67,7 @@ static long save_fp_state(struct pt_regs *regs, fstate_save(current, regs); err = __copy_to_user(state, ¤t->thread.fstate, sizeof(*state)); if (unlikely(err)) - return err; + return -EFAULT; /* We support no other extension state at this time. */ for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { @@ -87,8 +87,12 @@ static long restore_sigcontext(struct pt_regs *regs, struct sigcontext __user *sc) { long err; + /* sc_regs is structured the same as the start of pt_regs */ err = __copy_from_user(regs, &sc->sc_regs, sizeof(sc->sc_regs)); + if (unlikely(err)) + return -EFAULT; + /* Restore the floating-point state. */ if (has_fpu) err |= restore_fp_state(regs, &sc->sc_fpregs); @@ -140,8 +144,12 @@ static long setup_sigcontext(struct rt_sigframe __user *frame, { struct sigcontext __user *sc = &frame->uc.uc_mcontext; long err; + /* sc_regs is structured the same as the start of pt_regs */ err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); + if (unlikely(err)) + return -EFAULT; + /* Save the floating-point state. */ if (has_fpu) err |= save_fp_state(regs, &sc->sc_fpregs); -- 2.1.0 (2) or just leave it as it is and ignore this patch? Thanks, Tiezhu > > Note: setup_rt_frame -> setup_sigcontext -> save_fp_frame > >> >> Signed-off-by: Tiezhu Yang <yangtiezhu@loongson.cn> >> --- >> arch/riscv/kernel/signal.c | 6 +++++- >> 1 file changed, 5 insertions(+), 1 deletion(-) >> >> diff --git a/arch/riscv/kernel/signal.c b/arch/riscv/kernel/signal.c >> index 65942b3..2238fc5 100644 >> --- a/arch/riscv/kernel/signal.c >> +++ b/arch/riscv/kernel/signal.c >> @@ -67,7 +67,7 @@ static long save_fp_state(struct pt_regs *regs, >> fstate_save(current, regs); >> err = __copy_to_user(state, ¤t->thread.fstate, >> sizeof(*state)); >> if (unlikely(err)) >> - return err; >> + return -EFAULT; >> /* We support no other extension state at this time. */ >> for (i = 0; i < ARRAY_SIZE(sc_fpregs->q.reserved); i++) { >> @@ -140,8 +140,12 @@ static long setup_sigcontext(struct rt_sigframe >> __user *frame, >> { >> struct sigcontext __user *sc = &frame->uc.uc_mcontext; >> long err; >> + >> /* sc_regs is structured the same as the start of pt_regs */ >> err = __copy_to_user(&sc->sc_regs, regs, sizeof(sc->sc_regs)); >> + if (unlikely(err)) >> + return -EFAULT; >> + >> /* Save the floating-point state. */ >> if (has_fpu) >> err |= save_fp_state(regs, &sc->sc_fpregs); >> > > _______________________________________________ linux-riscv mailing list linux-riscv@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-riscv ^ permalink raw reply related [flat|nested] 6+ messages in thread
end of thread, other threads:[~2021-03-03 18:57 UTC | newest] Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- 2021-03-02 7:28 [PATCH] riscv: Return -EFAULT if copy_to_user() failed in signal.c Tiezhu Yang 2021-03-02 7:28 ` Tiezhu Yang 2021-03-02 10:01 ` Ben Dooks 2021-03-02 10:01 ` Ben Dooks 2021-03-03 1:53 ` Tiezhu Yang 2021-03-03 1:53 ` Tiezhu Yang
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