linux-kernel - [PATCH] tracing/syscalls: ignore numbers outside NR

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <1414620418-29472-1-git-send-email-rabin@rab.in>
Date:	Wed, 29 Oct 2014 23:06:58 +0100
From:	Rabin Vincent <rabin@....in>
To:	Steven Rostedt <rostedt@...dmis.org>,
	Ingo Molnar <mingo@...hat.com>
Cc:	linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	Rabin Vincent <rabin@....in>
Subject: [PATCH] tracing/syscalls: ignore numbers outside NR_syscalls' range

ARM has some private syscalls (for example, set_tls(2)) which lie
outside the range of NR_syscalls.  If any of these are called while
syscall tracing is being performed, out-of-bounds array access will
occur in the ftrace and perf sys_{enter,exit} handlers.

 # trace-cmd record -e raw_syscalls:* true && trace-cmd report
 ...
 true-653   [000]   384.675777: sys_enter:            NR 192 (0, 1000, 3, 4000022, ffffffff, 0)
 true-653   [000]   384.675812: sys_exit:             NR 192 = 1995915264
 true-653   [000]   384.675971: sys_enter:            NR 983045 (76f74480, 76f74000, 76f74b28, 76f74480, 76f76f74, 1)
 true-653   [000]   384.675988: sys_exit:             NR 983045 = 0
 ...

 # trace-cmd record -e syscalls:* true
 [   17.289329] Unable to handle kernel paging request at virtual address aaaaaace
 [   17.289590] pgd = 9e71c000
 [   17.289696] [aaaaaace] *pgd=00000000
 [   17.289985] Internal error: Oops: 5 [#1] PREEMPT SMP ARM
 [   17.290169] Modules linked in:
 [   17.290391] CPU: 0 PID: 704 Comm: true Not tainted 3.18.0-rc2+ #21
 [   17.290585] task: 9f4dab00 ti: 9e710000 task.ti: 9e710000
 [   17.290747] PC is at ftrace_syscall_enter+0x48/0x1f8
 [   17.290866] LR is at syscall_trace_enter+0x124/0x184

Fix this by ignoring out-of-NR_syscalls-bounds syscall numbers.

Signed-off-by: Rabin Vincent <rabin@....in>
---
 kernel/trace/trace_syscalls.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_syscalls.c b/kernel/trace/trace_syscalls.c
index 4dc8b79..29228c4 100644
--- a/kernel/trace/trace_syscalls.c
+++ b/kernel/trace/trace_syscalls.c
@@ -313,7 +313,7 @@ static void ftrace_syscall_enter(void *data, struct pt_regs *regs, long id)
 	int size;
 
 	syscall_nr = trace_get_syscall_nr(current, regs);
-	if (syscall_nr < 0)
+	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
 		return;
 
 	/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE) */
@@ -360,7 +360,7 @@ static void ftrace_syscall_exit(void *data, struct pt_regs *regs, long ret)
 	int syscall_nr;
 
 	syscall_nr = trace_get_syscall_nr(current, regs);
-	if (syscall_nr < 0)
+	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
 		return;
 
 	/* Here we're inside tp handler's rcu_read_lock_sched (__DO_TRACE()) */
@@ -567,7 +567,7 @@ static void perf_syscall_enter(void *ignore, struct pt_regs *regs, long id)
 	int size;
 
 	syscall_nr = trace_get_syscall_nr(current, regs);
-	if (syscall_nr < 0)
+	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
 		return;
 	if (!test_bit(syscall_nr, enabled_perf_enter_syscalls))
 		return;
@@ -641,7 +641,7 @@ static void perf_syscall_exit(void *ignore, struct pt_regs *regs, long ret)
 	int size;
 
 	syscall_nr = trace_get_syscall_nr(current, regs);
-	if (syscall_nr < 0)
+	if (syscall_nr < 0 || syscall_nr >= NR_syscalls)
 		return;
 	if (!test_bit(syscall_nr, enabled_perf_exit_syscalls))
 		return;
-- 
2.1.1

--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@...r.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/