<gregkh@xxxxxxxxxxxxxxxxxxx> writes: > This is a note to let you know that I've just added the patch titled > > signal/metag: Document a conflict with SI_USER with SIGFPE > > to the 4.15-stable tree which can be found at: > http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary > > The filename of the patch is: > signal-metag-document-a-conflict-with-si_user-with-sigfpe.patch > and it can be found in the queue-4.15 subdirectory. > > If you, or anyone else, feels it should not be added to the stable tree, > please let <stable@xxxxxxxxxxxxxxx> know about it. The patch is a noop functionality wise so I don't see the point of backporting it to stable. Eric > From foo@baz Mon Apr 9 10:16:32 CEST 2018 > From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > Date: Tue, 1 Aug 2017 10:37:40 -0500 > Subject: signal/metag: Document a conflict with SI_USER with SIGFPE > > From: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > > > [ Upstream commit b80328be53c215346b153769267b38f531d89b4f ] > > Setting si_code to 0 results in a userspace seeing an si_code of 0. > This is the same si_code as SI_USER. Posix and common sense requires > that SI_USER not be a signal specific si_code. As such this use of 0 > for the si_code is a pretty horribly broken ABI. > > Further use of si_code == 0 guaranteed that copy_siginfo_to_user saw a > value of __SI_KILL and now sees a value of SIL_KILL with the result > hat uid and pid fields are copied and which might copying the si_addr > field by accident but certainly not by design. Making this a very > flakey implementation. > > Utilizing FPE_FIXME siginfo_layout will now return SIL_FAULT and the > appropriate fields will reliably be copied. > > Possible ABI fixes includee: > - Send the signal without siginfo > - Don't generate a signal > - Possibly assign and use an appropriate si_code > - Don't handle cases which can't happen > > Cc: James Hogan <james.hogan@xxxxxxxxxx> > Cc: linux-metag@xxxxxxxxxxxxxxx > Ref: ac919f0883e5 ("metag: Traps") > Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx> > Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx> > Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> > --- > arch/metag/include/uapi/asm/siginfo.h | 7 +++++++ > arch/metag/kernel/traps.c | 2 +- > 2 files changed, 8 insertions(+), 1 deletion(-) > > --- a/arch/metag/include/uapi/asm/siginfo.h > +++ b/arch/metag/include/uapi/asm/siginfo.h > @@ -6,4 +6,11 @@ > > #include <asm-generic/siginfo.h> > > +/* > + * SIGFPE si_codes > + */ > +#ifdef __KERNEL__ > +#define FPE_FIXME 0 /* Broken dup of SI_USER */ > +#endif /* __KERNEL__ */ > + > #endif > --- a/arch/metag/kernel/traps.c > +++ b/arch/metag/kernel/traps.c > @@ -735,7 +735,7 @@ TBIRES fpe_handler(TBIRES State, int Sig > else if (error_state & TXSTAT_FPE_INEXACT_BIT) > info.si_code = FPE_FLTRES; > else > - info.si_code = 0; > + info.si_code = FPE_FIXME; > info.si_errno = 0; > info.si_addr = (__force void __user *)regs->ctx.CurrPC; > force_sig_info(SIGFPE, &info, current); > > > Patches currently in stable-queue which might be from ebiederm@xxxxxxxxxxxx are > > queue-4.15/signal-metag-document-a-conflict-with-si_user-with-sigfpe.patch > queue-4.15/signal-arm-document-conflicts-with-si_user-and-sigfpe.patch > queue-4.15/signal-powerpc-document-conflicts-with-si_user-and-sigfpe-and-sigtrap.patch