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authorMathieu Desnoyers <mathieu.desnoyers@efficios.com>2022-11-02 09:06:35 -0400
committerPeter Zijlstra <peterz@infradead.org>2022-11-14 09:58:32 +0100
commit448dca8c88755b768552e19bd1618be34ef6d1ff (patch)
tree77d5b4a80a5ff940342c114c5eff22c886c85a30 /kernel/rseq.c
parent094226ad94f471a9f19e8f8e7140a09c2625abaa (diff)
rseq: Use pr_warn_once() when deprecated/unknown ABI flags are encountered
These commits use WARN_ON_ONCE() and kill the offending processes when deprecated and unknown flags are encountered: commit c17a6ff93213 ("rseq: Kill process when unknown flags are encountered in ABI structures") commit 0190e4198e47 ("rseq: Deprecate RSEQ_CS_FLAG_NO_RESTART_ON_* flags") The WARN_ON_ONCE() triggered by userspace input prevents use of Syzkaller to fuzz the rseq system call. Replace this WARN_ON_ONCE() by pr_warn_once() messages which contain actually useful information. Reported-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org> Acked-by: Mark Rutland <mark.rutland@arm.com> Acked-by: Paul E. McKenney <paulmck@kernel.org> Link: https://lkml.kernel.org/r/20221102130635.7379-1-mathieu.desnoyers@efficios.com
Diffstat (limited to 'kernel/rseq.c')
-rw-r--r--kernel/rseq.c19
1 files changed, 17 insertions, 2 deletions
diff --git a/kernel/rseq.c b/kernel/rseq.c
index bda8175f8f99..d38ab944105d 100644
--- a/kernel/rseq.c
+++ b/kernel/rseq.c
@@ -171,12 +171,27 @@ static int rseq_get_rseq_cs(struct task_struct *t, struct rseq_cs *rseq_cs)
return 0;
}
+static bool rseq_warn_flags(const char *str, u32 flags)
+{
+ u32 test_flags;
+
+ if (!flags)
+ return false;
+ test_flags = flags & RSEQ_CS_NO_RESTART_FLAGS;
+ if (test_flags)
+ pr_warn_once("Deprecated flags (%u) in %s ABI structure", test_flags, str);
+ test_flags = flags & ~RSEQ_CS_NO_RESTART_FLAGS;
+ if (test_flags)
+ pr_warn_once("Unknown flags (%u) in %s ABI structure", test_flags, str);
+ return true;
+}
+
static int rseq_need_restart(struct task_struct *t, u32 cs_flags)
{
u32 flags, event_mask;
int ret;
- if (WARN_ON_ONCE(cs_flags & RSEQ_CS_NO_RESTART_FLAGS) || cs_flags)
+ if (rseq_warn_flags("rseq_cs", cs_flags))
return -EINVAL;
/* Get thread flags. */
@@ -184,7 +199,7 @@ static int rseq_need_restart(struct task_struct *t, u32 cs_flags)
if (ret)
return ret;
- if (WARN_ON_ONCE(flags & RSEQ_CS_NO_RESTART_FLAGS) || flags)
+ if (rseq_warn_flags("rseq", flags))
return -EINVAL;
/*