6.6-stable patches

added patches:
	sched-rt-disallow-writing-invalid-values-to-sched_rt_period_us.patch
	series

diff --git a/queue-6.6/sched-rt-disallow-writing-invalid-values-to-sched_rt_period_us.patch b/queue-6.6/sched-rt-disallow-writing-invalid-values-to-sched_rt_period_us.patch
new file mode 100644 (file)
index 0000000..268e220
--- /dev/null
+++ b/queue-6.6/sched-rt-disallow-writing-invalid-values-to-sched_rt_period_us.patch
@@ -0,0 +1,89 @@
+From 079be8fc630943d9fc70a97807feb73d169ee3fc Mon Sep 17 00:00:00 2001
+From: Cyril Hrubis <chrubis@suse.cz>
+Date: Mon, 2 Oct 2023 13:55:51 +0200
+Subject: sched/rt: Disallow writing invalid values to sched_rt_period_us
+
+From: Cyril Hrubis <chrubis@suse.cz>
+
+commit 079be8fc630943d9fc70a97807feb73d169ee3fc upstream.
+
+The validation of the value written to sched_rt_period_us was broken
+because:
+
+  - the sysclt_sched_rt_period is declared as unsigned int
+  - parsed by proc_do_intvec()
+  - the range is asserted after the value parsed by proc_do_intvec()
+
+Because of this negative values written to the file were written into a
+unsigned integer that were later on interpreted as large positive
+integers which did passed the check:
+
+  if (sysclt_sched_rt_period <= 0)
+       return EINVAL;
+
+This commit fixes the parsing by setting explicit range for both
+perid_us and runtime_us into the sched_rt_sysctls table and processes
+the values with proc_dointvec_minmax() instead.
+
+Alternatively if we wanted to use full range of unsigned int for the
+period value we would have to split the proc_handler and use
+proc_douintvec() for it however even the
+Documentation/scheduller/sched-rt-group.rst describes the range as 1 to
+INT_MAX.
+
+As far as I can tell the only problem this causes is that the sysctl
+file allows writing negative values which when read back may confuse
+userspace.
+
+There is also a LTP test being submitted for these sysctl files at:
+
+  http://patchwork.ozlabs.org/project/ltp/patch/20230901144433.2526-1-chrubis@suse.cz/
+
+Signed-off-by: Cyril Hrubis <chrubis@suse.cz>
+Signed-off-by: Ingo Molnar <mingo@kernel.org>
+Link: https://lore.kernel.org/r/20231002115553.3007-2-chrubis@suse.cz
+Cc: Mahmoud Adam <mngyadam@amazon.com>
+Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
+---
+ kernel/sched/rt.c |    9 +++++----
+ 1 file changed, 5 insertions(+), 4 deletions(-)
+
+--- a/kernel/sched/rt.c
++++ b/kernel/sched/rt.c
+@@ -37,6 +37,8 @@ static struct ctl_table sched_rt_sysctls
+               .maxlen         = sizeof(unsigned int),
+               .mode           = 0644,
+               .proc_handler   = sched_rt_handler,
++              .extra1         = SYSCTL_ONE,
++              .extra2         = SYSCTL_INT_MAX,
+       },
+       {
+               .procname       = "sched_rt_runtime_us",
+@@ -44,6 +46,8 @@ static struct ctl_table sched_rt_sysctls
+               .maxlen         = sizeof(int),
+               .mode           = 0644,
+               .proc_handler   = sched_rt_handler,
++              .extra1         = SYSCTL_NEG_ONE,
++              .extra2         = SYSCTL_INT_MAX,
+       },
+       {
+               .procname       = "sched_rr_timeslice_ms",
+@@ -2989,9 +2993,6 @@ static int sched_rt_global_constraints(v
+ #ifdef CONFIG_SYSCTL
+ static int sched_rt_global_validate(void)
+ {
+-      if (sysctl_sched_rt_period <= 0)
+-              return -EINVAL;
+-
+       if ((sysctl_sched_rt_runtime != RUNTIME_INF) &&
+               ((sysctl_sched_rt_runtime > sysctl_sched_rt_period) ||
+                ((u64)sysctl_sched_rt_runtime *
+@@ -3022,7 +3023,7 @@ static int sched_rt_handler(struct ctl_t
+       old_period = sysctl_sched_rt_period;
+       old_runtime = sysctl_sched_rt_runtime;
+ 
+-      ret = proc_dointvec(table, write, buffer, lenp, ppos);
++      ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
+ 
+       if (!ret && write) {
+               ret = sched_rt_global_validate();

diff --git a/queue-6.6/series b/queue-6.6/series
new file mode 100644 (file)
index 0000000..c955e85
--- /dev/null
+++ b/queue-6.6/series
@@ -0,0 +1 @@
+sched-rt-disallow-writing-invalid-values-to-sched_rt_period_us.patch