From 4a402463a7a4a4243c9c66600fd01ae800f959e3 Mon Sep 17 00:00:00 2001 From: AKASHI Takahiro Date: Wed, 9 Oct 2013 15:58:29 +0100 Subject: [PATCH] ARM: 7851/1: check for number of arguments in syscall_get/set_arguments() commit 3c1532df5c1b54b5f6246cdef94eeb73a39fe43a upstream. In ftrace_syscall_enter(), syscall_get_arguments(..., 0, n, ...) if (i == 0) { ...; n--;} memcpy(..., n * sizeof(args[0])); If 'number of arguments(n)' is zero and 'argument index(i)' is also zero in syscall_get_arguments(), none of arguments should be copied by memcpy(). Otherwise 'n--' can be a big positive number and unexpected amount of data will be copied. Tracing system calls which take no argument, say sync(void), may hit this case and eventually make the system corrupted. This patch fixes the issue both in syscall_get_arguments() and syscall_set_arguments(). Acked-by: Will Deacon Signed-off-by: AKASHI Takahiro Signed-off-by: Will Deacon Signed-off-by: Russell King Signed-off-by: Greg Kroah-Hartman --- arch/arm/include/asm/syscall.h | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h index f1d96d4..73ddd72 100644 --- a/arch/arm/include/asm/syscall.h +++ b/arch/arm/include/asm/syscall.h @@ -57,6 +57,9 @@ static inline void syscall_get_arguments(struct task_struct *task, unsigned int i, unsigned int n, unsigned long *args) { + if (n == 0) + return; + if (i + n > SYSCALL_MAX_ARGS) { unsigned long *args_bad = args + SYSCALL_MAX_ARGS - i; unsigned int n_bad = n + i - SYSCALL_MAX_ARGS; @@ -81,6 +84,9 @@ static inline void syscall_set_arguments(struct task_struct *task, unsigned int i, unsigned int n, const unsigned long *args) { + if (n == 0) + return; + if (i + n > SYSCALL_MAX_ARGS) { pr_warning("%s called with max args %d, handling only %d\n", __func__, i + n, SYSCALL_MAX_ARGS); -- 2.7.4