| Message ID | 20180422190639.lyfvgnzapo2mrpu6@salmiak (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 2018-04-22 21:06, Mark Rutland wrote: > On Sun, Apr 22, 2018 at 12:47:57PM +0200, Jan Kiszka wrote: >> Hi, >> >> this can be triggered simply by running >> >> # echo 0 > /sys/devices/system/cpu/cpu3/online >> # echo 1 > /sys/devices/system/cpu/cpu3/online >> >> [ 455.904854] ================================================================== >> [ 455.906108] BUG: KASAN: global-out-of-bounds in unmap_kernel_at_el0+0x70/0x1a0 >> [ 455.906668] Read of size 4 at addr ffff200008e3a9d8 by task swapper/3/0 > > It looks like we miss a sentinel in kpti_safe_list. > > Does the below help? > > Mark. > > ---->8---- > From ade322407e3d6d1f50e558ebd50d2c1c7bd811c2 Mon Sep 17 00:00:00 2001 > From: Mark Rutland <mark.rutland@arm.com> > Date: Sun, 22 Apr 2018 19:58:08 +0100 > Subject: [PATCH] arm64: add sentinel to kpti_safe_list > > We're missing a sentinel entry in kpti_safe_list. Thus is_midr_in_range_list() > can walk past the end of kpti_safe_list. Depending on the contents of memory, > this could erroneously match a CPU's MIDR, cause a data abort, or other bad > outcomes. > > Add the sentinel entry to avoid this. > > Fixes: be5b299830c63ed7 ("arm64: capabilities: Add support for checks based on a list of MIDRs") > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > Reported-by: Jan Kiszka <jan.kiszka@web.de> > Cc: Catalin Marinas <catalin.marinas@arm.com> > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > Cc: Will Deacon <will.deacon@arm.com> > --- > arch/arm64/kernel/cpufeature.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index 536d572e5596..9d1b06d67c53 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -868,6 +868,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, > static const struct midr_range kpti_safe_list[] = { > MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), > MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), > + { /* sentinel */ } > }; > char const *str = "command line option"; > > Jep, all fine now! Jan
On Mon, Apr 23, 2018 at 07:00:52AM +0200, Jan Kiszka wrote: > On 2018-04-22 21:06, Mark Rutland wrote: > > Does the below help? > > From ade322407e3d6d1f50e558ebd50d2c1c7bd811c2 Mon Sep 17 00:00:00 2001 > > From: Mark Rutland <mark.rutland@arm.com> > > Date: Sun, 22 Apr 2018 19:58:08 +0100 > > Subject: [PATCH] arm64: add sentinel to kpti_safe_list > > > > We're missing a sentinel entry in kpti_safe_list. Thus is_midr_in_range_list() > > can walk past the end of kpti_safe_list. Depending on the contents of memory, > > this could erroneously match a CPU's MIDR, cause a data abort, or other bad > > outcomes. > > > > Add the sentinel entry to avoid this. > > > > Fixes: be5b299830c63ed7 ("arm64: capabilities: Add support for checks based on a list of MIDRs") > > Signed-off-by: Mark Rutland <mark.rutland@arm.com> > > Reported-by: Jan Kiszka <jan.kiszka@web.de> > > Cc: Catalin Marinas <catalin.marinas@arm.com> > > Cc: Suzuki K Poulose <suzuki.poulose@arm.com> > > Cc: Will Deacon <will.deacon@arm.com> > > --- > > arch/arm64/kernel/cpufeature.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > > index 536d572e5596..9d1b06d67c53 100644 > > --- a/arch/arm64/kernel/cpufeature.c > > +++ b/arch/arm64/kernel/cpufeature.c > > @@ -868,6 +868,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, > > static const struct midr_range kpti_safe_list[] = { > > MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), > > MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), > > + { /* sentinel */ } > > }; > > char const *str = "command line option"; > > > > > > Jep, all fine now! Cool. Can I take that as a Tested-by? Mark.
On 2018-04-23 12:29, Mark Rutland wrote: > On Mon, Apr 23, 2018 at 07:00:52AM +0200, Jan Kiszka wrote: >> On 2018-04-22 21:06, Mark Rutland wrote: > >>> Does the below help? > >>> From ade322407e3d6d1f50e558ebd50d2c1c7bd811c2 Mon Sep 17 00:00:00 2001 >>> From: Mark Rutland <mark.rutland@arm.com> >>> Date: Sun, 22 Apr 2018 19:58:08 +0100 >>> Subject: [PATCH] arm64: add sentinel to kpti_safe_list >>> >>> We're missing a sentinel entry in kpti_safe_list. Thus is_midr_in_range_list() >>> can walk past the end of kpti_safe_list. Depending on the contents of memory, >>> this could erroneously match a CPU's MIDR, cause a data abort, or other bad >>> outcomes. >>> >>> Add the sentinel entry to avoid this. >>> >>> Fixes: be5b299830c63ed7 ("arm64: capabilities: Add support for checks based on a list of MIDRs") >>> Signed-off-by: Mark Rutland <mark.rutland@arm.com> >>> Reported-by: Jan Kiszka <jan.kiszka@web.de> >>> Cc: Catalin Marinas <catalin.marinas@arm.com> >>> Cc: Suzuki K Poulose <suzuki.poulose@arm.com> >>> Cc: Will Deacon <will.deacon@arm.com> >>> --- >>> arch/arm64/kernel/cpufeature.c | 1 + >>> 1 file changed, 1 insertion(+) >>> >>> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c >>> index 536d572e5596..9d1b06d67c53 100644 >>> --- a/arch/arm64/kernel/cpufeature.c >>> +++ b/arch/arm64/kernel/cpufeature.c >>> @@ -868,6 +868,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, >>> static const struct midr_range kpti_safe_list[] = { >>> MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), >>> MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), >>> + { /* sentinel */ } >>> }; >>> char const *str = "command line option"; >>> >>> >> >> Jep, all fine now! > > Cool. Can I take that as a Tested-by? Yes, sorry: Tested-by: Jan Kiszka <jan.kiszka@siemens.com> Jan
On Mon, Apr 23, 2018 at 12:33:17PM +0200, Jan Kiszka wrote: > On 2018-04-23 12:29, Mark Rutland wrote: > > On Mon, Apr 23, 2018 at 07:00:52AM +0200, Jan Kiszka wrote: > >> On 2018-04-22 21:06, Mark Rutland wrote: > > > >>> Does the below help? [...] > >> Jep, all fine now! > > > > Cool. Can I take that as a Tested-by? > > Yes, sorry: > > Tested-by: Jan Kiszka <jan.kiszka@siemens.com> > > Jan Cheers! I'll fix up the reported-by address likewise, and send this out as a patch. Thanks, Mark.
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index 536d572e5596..9d1b06d67c53 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -868,6 +868,7 @@ static bool unmap_kernel_at_el0(const struct arm64_cpu_capabilities *entry, static const struct midr_range kpti_safe_list[] = { MIDR_ALL_VERSIONS(MIDR_CAVIUM_THUNDERX2), MIDR_ALL_VERSIONS(MIDR_BRCM_VULCAN), + { /* sentinel */ } }; char const *str = "command line option";