diff options
| author | Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | 2022-11-02 09:06:35 -0400 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-11-14 09:58:32 +0100 |
| commit | 448dca8c88755b768552e19bd1618be34ef6d1ff (patch) | |
| tree | 77d5b4a80a5ff940342c114c5eff22c886c85a30 /kernel | |
| parent | 094226ad94f471a9f19e8f8e7140a09c2625abaa (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')
| -rw-r--r-- | kernel/rseq.c | 19 |
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; /* |