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authorAKASHI Takahiro <takahiro.akashi@linaro.org>2013-10-09 15:58:29 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-11-04 04:31:06 -0800
commit4a402463a7a4a4243c9c66600fd01ae800f959e3 (patch)
tree780d93bf9ea1d3e4902e1eb3d29f9c1c492fb65d /arch
parent9babd8ab0192070535fe1bab8b86d1c7b1e71943 (diff)
downloadvexpress-lsk-4a402463a7a4a4243c9c66600fd01ae800f959e3.tar.gz
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) { <handle ORIG_r0> ...; 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 <will.deacon@arm.com> Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Signed-off-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'arch')
-rw-r--r--arch/arm/include/asm/syscall.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm/include/asm/syscall.h b/arch/arm/include/asm/syscall.h
index f1d96d4e809..73ddd7239b3 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);