From b69fb7699c92f85991672fc144b0adb7c717fbc8 Mon Sep 17 00:00:00 2001 From: David Ahern Date: Mon, 15 Jun 2015 16:15:45 -0400 Subject: sparc64: perf: Add sanity checking on addresses in user stack Processes are getting killed (sigbus or segv) while walking userspace callchains when using perf. In some instances I have seen ufp = 0x7ff which does not seem like a proper stack address. This patch adds a function to run validity checks against the address before attempting the copy_from_user. The checks are copied from the x86 version as a start point with the addition of a 4-byte alignment check. Signed-off-by: David Ahern Signed-off-by: David S. Miller --- arch/sparc/kernel/perf_event.c | 13 +++++++++++++ 1 file changed, 13 insertions(+) (limited to 'arch/sparc/kernel/perf_event.c') diff --git a/arch/sparc/kernel/perf_event.c b/arch/sparc/kernel/perf_event.c index 48387be665e9..a665e3f8c6c6 100644 --- a/arch/sparc/kernel/perf_event.c +++ b/arch/sparc/kernel/perf_event.c @@ -1741,6 +1741,16 @@ void perf_callchain_kernel(struct perf_callchain_entry *entry, } while (entry->nr < PERF_MAX_STACK_DEPTH); } +static inline int +valid_user_frame(const void __user *fp, unsigned long size) +{ + /* addresses should be at least 4-byte aligned */ + if (((unsigned long) fp) & 3) + return 0; + + return (__range_not_ok(fp, size, TASK_SIZE) == 0); +} + static void perf_callchain_user_64(struct perf_callchain_entry *entry, struct pt_regs *regs) { @@ -1753,6 +1763,9 @@ static void perf_callchain_user_64(struct perf_callchain_entry *entry, unsigned long pc; usf = (struct sparc_stackf __user *)ufp; + if (!valid_user_frame(usf, sizeof(sf))) + break; + if (__copy_from_user_inatomic(&sf, usf, sizeof(sf))) break; -- cgit v1.2.3