From: Will Deacon <will@kernel.org> To: Dave Martin <Dave.Martin@arm.com> Cc: mtk.manpages@gmail.com, linux-man@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Catalin Marinas <catalin.marinas@arm.com>, Amit Daniel Kachhap <amit.kachhap@arm.com>, Mark Rutland <mark.rutland@arm.com> Subject: Re: [PATCH 14/14] prctl.2: Add PR_PAC_RESET_KEYS (arm64) Date: Wed, 13 May 2020 08:25:31 +0100 [thread overview] Message-ID: <20200513072530.GA18196@willie-the-truck> (raw) In-Reply-To: <1589301419-24459-15-git-send-email-Dave.Martin@arm.com> Hi Dave, On Tue, May 12, 2020 at 05:36:59PM +0100, Dave Martin wrote: > diff --git a/man2/prctl.2 b/man2/prctl.2 > index dd16227..7ea60e2 100644 > --- a/man2/prctl.2 > +++ b/man2/prctl.2 > @@ -950,6 +950,46 @@ behavior. > A value of 1 indicates > .BR execve (2) > will operate in the privilege-restricting mode described above. > +.\" prctl PR_PAC_RESET_KEYS > +.\" commit ba830885656414101b2f8ca88786524d4bb5e8c1 > +.TP > +.BR PR_PAC_RESET_KEYS " (since Linux 5.0, only on arm64)" > +Securely reset the thread's pointer authentication keys > +to fresh random values generated by the kernel. > +.IP > +The set of keys to be reset is specified by > +.IR arg2 , > +which must be a logical OR of zero or more of the following: > +.RS > +.TP > +.B PR_PAC_APIAKEY > +instruction authentication key A > +.TP > +.B PR_PAC_APIBKEY > +instruction authentication key B > +.TP > +.B PR_PAC_APDAKEY > +data authentication key A > +.TP > +.B PR_PAC_APDBKEY > +data authentication key B > +.TP > +.B PR_PAC_APGAKEY > +generic authentication \(lqA\(rq key. > +.IP > +(Yes folks, there really is no generic B key.) > +.RE > +.IP > +As a special case, if > +.I arg2 > +is zero then all the keys are reset. > +Since new keys could be added in future, > +this is the recommended way to completely wipe the existing keys > +when creating a new execution context. I see what you're saying, but the keys are also reset on exec() iirc, so we don't want to encourage people to issue the prctl() unnecessarily immediately following an exec(). > +.IP > +The remaining arguments > +.IR arg3 ", " arg4 " and " arg5 > +must all be zero. > .\" prctl PR_SET_PDEATHSIG > .TP > .BR PR_SET_PDEATHSIG " (since Linux 2.1.57)" > @@ -1920,6 +1960,27 @@ are not 0. > .B EINVAL > .I option > was > +.B PR_PAC_RESET_KEYS > +and > +.I arg2 > +contains non-zero bits other than > +.BR > +.BR PR_PAC_APIAKEY , > +.BR PR_PAC_APIBKEY , > +.BR PR_PAC_APDAKEY , > +.B PR_PAC_APDBKEY > +and > +.BR PR_PAC_APGAKEY ; > +or > +.IR arg3 , > +.I arg4 > +and > +.I arg5 > +were not all zero. Do we care about other reasons for -EINVAL, such as the system not supporting pointer authentication? Will
WARNING: multiple messages have this Message-ID (diff)
From: Will Deacon <will@kernel.org> To: Dave Martin <Dave.Martin@arm.com> Cc: linux-arch@vger.kernel.org, linux-man@vger.kernel.org, Catalin Marinas <catalin.marinas@arm.com>, mtk.manpages@gmail.com, Amit Daniel Kachhap <amit.kachhap@arm.com>, Mark Rutland <mark.rutland@arm.com>, linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH 14/14] prctl.2: Add PR_PAC_RESET_KEYS (arm64) Date: Wed, 13 May 2020 08:25:31 +0100 [thread overview] Message-ID: <20200513072530.GA18196@willie-the-truck> (raw) In-Reply-To: <1589301419-24459-15-git-send-email-Dave.Martin@arm.com> Hi Dave, On Tue, May 12, 2020 at 05:36:59PM +0100, Dave Martin wrote: > diff --git a/man2/prctl.2 b/man2/prctl.2 > index dd16227..7ea60e2 100644 > --- a/man2/prctl.2 > +++ b/man2/prctl.2 > @@ -950,6 +950,46 @@ behavior. > A value of 1 indicates > .BR execve (2) > will operate in the privilege-restricting mode described above. > +.\" prctl PR_PAC_RESET_KEYS > +.\" commit ba830885656414101b2f8ca88786524d4bb5e8c1 > +.TP > +.BR PR_PAC_RESET_KEYS " (since Linux 5.0, only on arm64)" > +Securely reset the thread's pointer authentication keys > +to fresh random values generated by the kernel. > +.IP > +The set of keys to be reset is specified by > +.IR arg2 , > +which must be a logical OR of zero or more of the following: > +.RS > +.TP > +.B PR_PAC_APIAKEY > +instruction authentication key A > +.TP > +.B PR_PAC_APIBKEY > +instruction authentication key B > +.TP > +.B PR_PAC_APDAKEY > +data authentication key A > +.TP > +.B PR_PAC_APDBKEY > +data authentication key B > +.TP > +.B PR_PAC_APGAKEY > +generic authentication \(lqA\(rq key. > +.IP > +(Yes folks, there really is no generic B key.) > +.RE > +.IP > +As a special case, if > +.I arg2 > +is zero then all the keys are reset. > +Since new keys could be added in future, > +this is the recommended way to completely wipe the existing keys > +when creating a new execution context. I see what you're saying, but the keys are also reset on exec() iirc, so we don't want to encourage people to issue the prctl() unnecessarily immediately following an exec(). > +.IP > +The remaining arguments > +.IR arg3 ", " arg4 " and " arg5 > +must all be zero. > .\" prctl PR_SET_PDEATHSIG > .TP > .BR PR_SET_PDEATHSIG " (since Linux 2.1.57)" > @@ -1920,6 +1960,27 @@ are not 0. > .B EINVAL > .I option > was > +.B PR_PAC_RESET_KEYS > +and > +.I arg2 > +contains non-zero bits other than > +.BR > +.BR PR_PAC_APIAKEY , > +.BR PR_PAC_APIBKEY , > +.BR PR_PAC_APDAKEY , > +.B PR_PAC_APDBKEY > +and > +.BR PR_PAC_APGAKEY ; > +or > +.IR arg3 , > +.I arg4 > +and > +.I arg5 > +were not all zero. Do we care about other reasons for -EINVAL, such as the system not supporting pointer authentication? Will _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel
next prev parent reply other threads:[~2020-05-13 7:25 UTC|newest] Thread overview: 149+ messages / expand[flat|nested] mbox.gz Atom feed top 2020-05-12 16:36 [PATCH 00/14] prctl.2 man page updates for Linux 5.6 Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` [PATCH 01/14] prctl.2: tfix clarify that prctl can apply to threads Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 8:30 ` Michael Kerrisk (man-pages) 2020-05-13 8:30 ` Michael Kerrisk (man-pages) 2020-05-13 8:30 ` Michael Kerrisk (man-pages) 2020-05-12 16:36 ` [PATCH 02/14] prctl.2: Add health warning Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 10:10 ` Michael Kerrisk (man-pages) 2020-05-13 10:10 ` Michael Kerrisk (man-pages) 2020-05-13 10:10 ` Michael Kerrisk (man-pages) 2020-05-13 11:13 ` Dave Martin 2020-05-13 11:13 ` Dave Martin 2020-05-13 11:40 ` Michael Kerrisk (man-pages) 2020-05-13 11:40 ` Michael Kerrisk (man-pages) 2020-05-13 11:40 ` Michael Kerrisk (man-pages) 2020-05-13 11:41 ` Dave Martin 2020-05-13 11:41 ` Dave Martin 2020-05-13 11:41 ` Dave Martin 2020-05-12 16:36 ` [PATCH 03/14] prctl.2: tfix mis-description of thread ID values in procfs Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 8:36 ` Michael Kerrisk (man-pages) 2020-05-13 8:36 ` Michael Kerrisk (man-pages) 2020-05-12 16:36 ` [PATCH 04/14] prctl.2: srcfix add comments for navigation Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 10:09 ` Michael Kerrisk (man-pages) 2020-05-13 10:09 ` Michael Kerrisk (man-pages) 2020-05-13 10:56 ` Dave Martin 2020-05-13 10:56 ` Dave Martin 2020-05-13 11:03 ` Michael Kerrisk (man-pages) 2020-05-13 11:03 ` Michael Kerrisk (man-pages) 2020-05-13 11:03 ` Michael Kerrisk (man-pages) 2020-05-13 11:15 ` Dave Martin 2020-05-13 11:15 ` Dave Martin 2020-05-13 11:48 ` Michael Kerrisk (man-pages) 2020-05-13 11:48 ` Michael Kerrisk (man-pages) 2020-05-13 11:48 ` Michael Kerrisk (man-pages) 2020-05-13 11:51 ` Dave Martin 2020-05-13 11:51 ` Dave Martin 2020-05-13 11:51 ` Dave Martin 2020-05-12 16:36 ` [PATCH 05/14] prctl.2: tfix listing order of prctls Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 10:10 ` Michael Kerrisk (man-pages) 2020-05-13 10:10 ` Michael Kerrisk (man-pages) 2020-05-13 11:21 ` Dave Martin 2020-05-13 11:21 ` Dave Martin 2020-05-13 11:21 ` Dave Martin 2020-05-13 11:31 ` Michael Kerrisk (man-pages) 2020-05-13 11:31 ` Michael Kerrisk (man-pages) 2020-05-13 11:31 ` Michael Kerrisk (man-pages) 2020-05-13 11:45 ` Dave Martin 2020-05-13 11:45 ` Dave Martin 2020-05-13 11:45 ` Dave Martin 2020-05-12 16:36 ` [PATCH 06/14] prctl.2: ffix quotation mark tweaks Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 10:11 ` Michael Kerrisk (man-pages) 2020-05-13 10:11 ` Michael Kerrisk (man-pages) 2020-05-13 10:11 ` Michael Kerrisk (man-pages) 2020-05-13 11:39 ` Dave Martin 2020-05-13 11:39 ` Dave Martin 2020-05-13 11:39 ` Dave Martin 2020-05-13 11:46 ` Michael Kerrisk (man-pages) 2020-05-13 11:46 ` Michael Kerrisk (man-pages) 2020-05-13 11:51 ` Dave Martin 2020-05-13 11:51 ` Dave Martin 2020-05-13 11:51 ` Dave Martin 2020-05-12 16:36 ` [PATCH 07/14] prctl.2: Document removal of Intel MPX prctls Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:41 ` Dave Hansen 2020-05-12 16:41 ` Dave Hansen 2020-05-13 10:11 ` Michael Kerrisk (man-pages) 2020-05-13 10:11 ` Michael Kerrisk (man-pages) 2020-05-13 10:11 ` Michael Kerrisk (man-pages) 2020-05-12 16:36 ` [PATCH 08/14] prctl.2: Work around bogus constant "maxsig" in PR_SET_PDEATHSIG Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 10:30 ` Michael Kerrisk (man-pages) 2020-05-13 10:30 ` Michael Kerrisk (man-pages) 2020-05-13 10:30 ` Michael Kerrisk (man-pages) 2020-05-12 16:36 ` [PATCH 09/14] prctl.2: tfix minor punctuation in SPECULATION_CTRL prctls Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 10:31 ` Michael Kerrisk (man-pages) 2020-05-13 10:31 ` Michael Kerrisk (man-pages) 2020-05-13 10:31 ` Michael Kerrisk (man-pages) 2020-05-12 16:36 ` [PATCH 10/14] prctl.2: Add PR_SPEC_INDIRECT_BRANCH for " Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 11:21 ` Michael Kerrisk (man-pages) 2020-05-13 11:21 ` Michael Kerrisk (man-pages) 2020-05-13 11:21 ` Michael Kerrisk (man-pages) 2020-05-13 11:49 ` Dave Martin 2020-05-13 11:49 ` Dave Martin 2020-05-13 12:06 ` Michael Kerrisk (man-pages) 2020-05-13 12:06 ` Michael Kerrisk (man-pages) 2020-05-13 12:06 ` Michael Kerrisk (man-pages) 2020-05-13 13:53 ` Dave Martin 2020-05-13 13:53 ` Dave Martin 2020-05-13 13:53 ` Dave Martin 2020-05-12 16:36 ` [PATCH 11/14] prctl.2: Add PR_SPEC_DISABLE_NOEXEC " Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` [PATCH 12/14] prctl.2: Clarify the unsupported hardware case of EINVAL Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 10:48 ` Michael Kerrisk (man-pages) 2020-05-13 10:48 ` Michael Kerrisk (man-pages) 2020-05-12 16:36 ` [PATCH 13/14] prctl.2: Add SVE prctls (arm64) Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 8:43 ` Will Deacon 2020-05-13 8:43 ` Will Deacon 2020-05-13 8:43 ` Will Deacon 2020-05-13 10:46 ` Dave Martin 2020-05-13 10:46 ` Dave Martin 2020-05-13 10:46 ` Dave Martin 2020-05-13 11:01 ` Michael Kerrisk (man-pages) 2020-05-13 11:01 ` Michael Kerrisk (man-pages) 2020-05-13 14:02 ` Dave Martin 2020-05-13 14:02 ` Dave Martin 2020-05-13 14:02 ` Dave Martin 2020-05-13 21:11 ` Will Deacon 2020-05-13 21:11 ` Will Deacon 2020-05-13 21:11 ` Will Deacon 2020-05-18 16:37 ` Dave Martin 2020-05-18 16:37 ` Dave Martin 2020-05-26 14:45 ` Dave Martin 2020-05-26 14:45 ` Dave Martin 2020-05-12 16:36 ` [PATCH 14/14] prctl.2: Add PR_PAC_RESET_KEYS (arm64) Dave Martin 2020-05-12 16:36 ` Dave Martin 2020-05-13 7:25 ` Will Deacon [this message] 2020-05-13 7:25 ` Will Deacon 2020-05-13 14:36 ` Dave Martin 2020-05-13 14:36 ` Dave Martin 2020-05-13 14:36 ` Dave Martin 2020-05-13 21:00 ` Will Deacon 2020-05-13 21:00 ` Will Deacon 2020-05-13 21:00 ` Will Deacon 2020-05-18 16:11 ` Dave Martin 2020-05-18 16:11 ` Dave Martin 2020-05-18 16:11 ` Dave Martin 2020-05-18 16:29 ` Will Deacon 2020-05-18 16:29 ` Will Deacon 2020-05-18 16:29 ` Will Deacon 2020-05-13 11:28 ` [PATCH 00/14] prctl.2 man page updates for Linux 5.6 Michael Kerrisk (man-pages) 2020-05-13 11:28 ` Michael Kerrisk (man-pages)
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