* [PATCH] seccomp: don't block getters for resource control syscalls
@ 2021-06-30 16:05 Daniel P. Berrangé
2021-06-30 17:13 ` Dr. David Alan Gilbert
2021-07-01 7:15 ` Eduardo Otubo
0 siblings, 2 replies; 3+ messages in thread
From: Daniel P. Berrangé @ 2021-06-30 16:05 UTC (permalink / raw)
To: qemu-devel
Cc: Eduardo Otubo, Florian Weimer, Daniel P. Berrangé,
Dr . David Alan Gilbert
Recent GLibC calls sched_getaffinity in code paths related to malloc and
when QEMU blocks access, it sends it off into a bad codepath resulting
in stack exhaustion[1]. The GLibC bug is being fixed[2], but none the
less, GLibC has valid reasons to want to use sched_getaffinity.
It is not unreasonable for code to want to run many resource syscalls
for information gathering, so it is a bit too harsh for QEMU to block
them.
[1] https://bugzilla.redhat.com/show_bug.cgi?id=1975693
[2] https://sourceware.org/pipermail/libc-alpha/2021-June/128271.html
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
---
softmmu/qemu-seccomp.c | 6 ------
1 file changed, 6 deletions(-)
diff --git a/softmmu/qemu-seccomp.c b/softmmu/qemu-seccomp.c
index 9c29d9cf00..f50026778c 100644
--- a/softmmu/qemu-seccomp.c
+++ b/softmmu/qemu-seccomp.c
@@ -97,17 +97,11 @@ static const struct QemuSeccompSyscall denylist[] = {
{ SCMP_SYS(vfork), QEMU_SECCOMP_SET_SPAWN },
{ SCMP_SYS(execve), QEMU_SECCOMP_SET_SPAWN },
/* resource control */
- { SCMP_SYS(getpriority), QEMU_SECCOMP_SET_RESOURCECTL },
{ SCMP_SYS(setpriority), QEMU_SECCOMP_SET_RESOURCECTL },
{ SCMP_SYS(sched_setparam), QEMU_SECCOMP_SET_RESOURCECTL },
- { SCMP_SYS(sched_getparam), QEMU_SECCOMP_SET_RESOURCECTL },
{ SCMP_SYS(sched_setscheduler), QEMU_SECCOMP_SET_RESOURCECTL,
ARRAY_SIZE(sched_setscheduler_arg), sched_setscheduler_arg },
- { SCMP_SYS(sched_getscheduler), QEMU_SECCOMP_SET_RESOURCECTL },
{ SCMP_SYS(sched_setaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
- { SCMP_SYS(sched_getaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
- { SCMP_SYS(sched_get_priority_max), QEMU_SECCOMP_SET_RESOURCECTL },
- { SCMP_SYS(sched_get_priority_min), QEMU_SECCOMP_SET_RESOURCECTL },
};
static inline __attribute__((unused)) int
--
2.31.1
^ permalink raw reply related [flat|nested] 3+ messages in thread
* Re: [PATCH] seccomp: don't block getters for resource control syscalls
2021-06-30 16:05 [PATCH] seccomp: don't block getters for resource control syscalls Daniel P. Berrangé
@ 2021-06-30 17:13 ` Dr. David Alan Gilbert
2021-07-01 7:15 ` Eduardo Otubo
1 sibling, 0 replies; 3+ messages in thread
From: Dr. David Alan Gilbert @ 2021-06-30 17:13 UTC (permalink / raw)
To: Daniel P. Berrangé; +Cc: Eduardo Otubo, Florian Weimer, qemu-devel
* Daniel P. Berrangé (berrange@redhat.com) wrote:
> Recent GLibC calls sched_getaffinity in code paths related to malloc and
> when QEMU blocks access, it sends it off into a bad codepath resulting
> in stack exhaustion[1]. The GLibC bug is being fixed[2], but none the
> less, GLibC has valid reasons to want to use sched_getaffinity.
>
> It is not unreasonable for code to want to run many resource syscalls
> for information gathering, so it is a bit too harsh for QEMU to block
> them.
>
> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1975693
> [2] https://sourceware.org/pipermail/libc-alpha/2021-June/128271.html
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
> ---
> softmmu/qemu-seccomp.c | 6 ------
> 1 file changed, 6 deletions(-)
>
> diff --git a/softmmu/qemu-seccomp.c b/softmmu/qemu-seccomp.c
> index 9c29d9cf00..f50026778c 100644
> --- a/softmmu/qemu-seccomp.c
> +++ b/softmmu/qemu-seccomp.c
> @@ -97,17 +97,11 @@ static const struct QemuSeccompSyscall denylist[] = {
> { SCMP_SYS(vfork), QEMU_SECCOMP_SET_SPAWN },
> { SCMP_SYS(execve), QEMU_SECCOMP_SET_SPAWN },
> /* resource control */
> - { SCMP_SYS(getpriority), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(setpriority), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_setparam), QEMU_SECCOMP_SET_RESOURCECTL },
> - { SCMP_SYS(sched_getparam), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_setscheduler), QEMU_SECCOMP_SET_RESOURCECTL,
> ARRAY_SIZE(sched_setscheduler_arg), sched_setscheduler_arg },
> - { SCMP_SYS(sched_getscheduler), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_setaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
> - { SCMP_SYS(sched_getaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
> - { SCMP_SYS(sched_get_priority_max), QEMU_SECCOMP_SET_RESOURCECTL },
> - { SCMP_SYS(sched_get_priority_min), QEMU_SECCOMP_SET_RESOURCECTL },
> };
>
> static inline __attribute__((unused)) int
> --
> 2.31.1
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: [PATCH] seccomp: don't block getters for resource control syscalls
2021-06-30 16:05 [PATCH] seccomp: don't block getters for resource control syscalls Daniel P. Berrangé
2021-06-30 17:13 ` Dr. David Alan Gilbert
@ 2021-07-01 7:15 ` Eduardo Otubo
1 sibling, 0 replies; 3+ messages in thread
From: Eduardo Otubo @ 2021-07-01 7:15 UTC (permalink / raw)
To: Daniel P. Berrangé
Cc: Florian Weimer, qemu-devel, Dr . David Alan Gilbert
[-- Attachment #1: Type: text/plain, Size: 2152 bytes --]
On 30/06/2021 - 17:05:26, Daniel P. Berrange wrote:
> Recent GLibC calls sched_getaffinity in code paths related to malloc and
> when QEMU blocks access, it sends it off into a bad codepath resulting
> in stack exhaustion[1]. The GLibC bug is being fixed[2], but none the
> less, GLibC has valid reasons to want to use sched_getaffinity.
>
> It is not unreasonable for code to want to run many resource syscalls
> for information gathering, so it is a bit too harsh for QEMU to block
> them.
>
> [1] https://bugzilla.redhat.com/show_bug.cgi?id=1975693
> [2] https://sourceware.org/pipermail/libc-alpha/2021-June/128271.html
> Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
> ---
> softmmu/qemu-seccomp.c | 6 ------
> 1 file changed, 6 deletions(-)
>
> diff --git a/softmmu/qemu-seccomp.c b/softmmu/qemu-seccomp.c
> index 9c29d9cf00..f50026778c 100644
> --- a/softmmu/qemu-seccomp.c
> +++ b/softmmu/qemu-seccomp.c
> @@ -97,17 +97,11 @@ static const struct QemuSeccompSyscall denylist[] = {
> { SCMP_SYS(vfork), QEMU_SECCOMP_SET_SPAWN },
> { SCMP_SYS(execve), QEMU_SECCOMP_SET_SPAWN },
> /* resource control */
> - { SCMP_SYS(getpriority), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(setpriority), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_setparam), QEMU_SECCOMP_SET_RESOURCECTL },
> - { SCMP_SYS(sched_getparam), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_setscheduler), QEMU_SECCOMP_SET_RESOURCECTL,
> ARRAY_SIZE(sched_setscheduler_arg), sched_setscheduler_arg },
> - { SCMP_SYS(sched_getscheduler), QEMU_SECCOMP_SET_RESOURCECTL },
> { SCMP_SYS(sched_setaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
> - { SCMP_SYS(sched_getaffinity), QEMU_SECCOMP_SET_RESOURCECTL },
> - { SCMP_SYS(sched_get_priority_max), QEMU_SECCOMP_SET_RESOURCECTL },
> - { SCMP_SYS(sched_get_priority_min), QEMU_SECCOMP_SET_RESOURCECTL },
> };
>
> static inline __attribute__((unused)) int
> --
> 2.31.1
>
Acked-by: Eduardo Otubo <otubo@redhat.com>
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2021-06-30 16:05 [PATCH] seccomp: don't block getters for resource control syscalls Daniel P. Berrangé
2021-06-30 17:13 ` Dr. David Alan Gilbert
2021-07-01 7:15 ` Eduardo Otubo
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