unimore/kernel-hacking-2024-linux-steffo
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signal: Implement SIL_FAULT_TRAPNO

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Now that si_trapno is part of the union in _si_fault and available on
all architectures, add SIL_FAULT_TRAPNO and update siginfo_layout to
return SIL_FAULT_TRAPNO when the code assumes si_trapno is valid.

There is room for future changes to reduce when si_trapno is valid but
this is all that is needed to make si_trapno and the other members of
the the union in _sigfault mutually exclusive.

Update the code that uses siginfo_layout to deal with SIL_FAULT_TRAPNO
and have the same code ignore si_trapno in in all other cases.

v1: https://lkml.kernel.org/r/m1o8dvs7s7.fsf_-_@fess.ebiederm.org
v2: https://lkml.kernel.org/r/20210505141101.11519-6-ebiederm@xmission.com
Link: https://lkml.kernel.org/r/20210517195748.8880-2-ebiederm@xmission.com
Reviewed-by: Marco Elver <elver@google.com>
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
This commit is contained in:
Eric W. Biederman 2021-04-30 17:29:36 -05:00
parent add0b32ef9
commit 9abcabe311
3 changed files with 16 additions and 27 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

8
fs/signalfd.c
View file

@ -123,15 +123,13 @@ static int signalfd_copyinfo(struct signalfd_siginfo __user *uinfo,
*/
case SIL_FAULT:
new.ssi_addr = (long) kinfo->si_addr;
#ifdef __ARCH_SI_TRAPNO
break;
case SIL_FAULT_TRAPNO:
new.ssi_addr = (long) kinfo->si_addr;
new.ssi_trapno = kinfo->si_trapno;
#endif
break;
case SIL_FAULT_MCEERR:
new.ssi_addr = (long) kinfo->si_addr;
#ifdef __ARCH_SI_TRAPNO
new.ssi_trapno = kinfo->si_trapno;
#endif
new.ssi_addr_lsb = (short) kinfo->si_addr_lsb;
break;
case SIL_PERF_EVENT:

1
include/linux/signal.h
View file

@ -40,6 +40,7 @@ enum siginfo_layout {
SIL_TIMER,
SIL_POLL,
SIL_FAULT,
SIL_FAULT_TRAPNO,
SIL_FAULT_MCEERR,
SIL_FAULT_BNDERR,
SIL_FAULT_PKUERR,

34
kernel/signal.c
View file

@ -1194,6 +1194,7 @@ static inline bool has_si_pid_and_uid(struct kernel_siginfo *info)
case SIL_TIMER:
case SIL_POLL:
case SIL_FAULT:
case SIL_FAULT_TRAPNO:
case SIL_FAULT_MCEERR:
case SIL_FAULT_BNDERR:
case SIL_FAULT_PKUERR:
@ -2527,6 +2528,7 @@ static void hide_si_addr_tag_bits(struct ksignal *ksig)
{
switch (siginfo_layout(ksig->sig, ksig->info.si_code)) {
case SIL_FAULT:
case SIL_FAULT_TRAPNO:
case SIL_FAULT_MCEERR:
case SIL_FAULT_BNDERR:
case SIL_FAULT_PKUERR:
@ -3214,6 +3216,10 @@ enum siginfo_layout siginfo_layout(unsigned sig, int si_code)
#endif
else if ((sig == SIGTRAP) && (si_code == TRAP_PERF))
layout = SIL_PERF_EVENT;
#ifdef __ARCH_SI_TRAPNO
else if (layout == SIL_FAULT)
layout = SIL_FAULT_TRAPNO;
#endif
}
else if (si_code <= NSIGPOLL)
layout = SIL_POLL;
@ -3317,30 +3323,22 @@ void copy_siginfo_to_external32(struct compat_siginfo *to,
break;
case SIL_FAULT:
to->si_addr = ptr_to_compat(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
break;
case SIL_FAULT_TRAPNO:
to->si_addr = ptr_to_compat(from->si_addr);
to->si_trapno = from->si_trapno;
#endif
break;
case SIL_FAULT_MCEERR:
to->si_addr = ptr_to_compat(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
to->si_trapno = from->si_trapno;
#endif
to->si_addr_lsb = from->si_addr_lsb;
break;
case SIL_FAULT_BNDERR:
to->si_addr = ptr_to_compat(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
to->si_trapno = from->si_trapno;
#endif
to->si_lower = ptr_to_compat(from->si_lower);
to->si_upper = ptr_to_compat(from->si_upper);
break;
case SIL_FAULT_PKUERR:
to->si_addr = ptr_to_compat(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
to->si_trapno = from->si_trapno;
#endif
to->si_pkey = from->si_pkey;
break;
case SIL_PERF_EVENT:
@ -3401,30 +3399,22 @@ static int post_copy_siginfo_from_user32(kernel_siginfo_t *to,
break;
case SIL_FAULT:
to->si_addr = compat_ptr(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
break;
case SIL_FAULT_TRAPNO:
to->si_addr = compat_ptr(from->si_addr);
to->si_trapno = from->si_trapno;
#endif
break;
case SIL_FAULT_MCEERR:
to->si_addr = compat_ptr(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
to->si_trapno = from->si_trapno;
#endif
to->si_addr_lsb = from->si_addr_lsb;
break;
case SIL_FAULT_BNDERR:
to->si_addr = compat_ptr(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
to->si_trapno = from->si_trapno;
#endif
to->si_lower = compat_ptr(from->si_lower);
to->si_upper = compat_ptr(from->si_upper);
break;
case SIL_FAULT_PKUERR:
to->si_addr = compat_ptr(from->si_addr);
#ifdef __ARCH_SI_TRAPNO
to->si_trapno = from->si_trapno;
#endif
to->si_pkey = from->si_pkey;
break;
case SIL_PERF_EVENT: