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authorAKASHI Takahiro <takahiro.akashi@linaro.org>2013-10-03 06:47:44 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-09 12:24:26 -0800
commite2956ef5b5ddb3ede70962afe9297d8340787fa6 (patch)
treeaded66b49437a8da6e42f3d9d0e652c9c11d9c6f
parent2bf5861acf602fe6201ac1f82955ac7283e56b6f (diff)
arm64: check for number of arguments in syscall_get/set_arguments()
commit 7b22c03536a539142f931815528d55df455ffe2d upstream. In ftrace_syscall_enter(), syscall_get_arguments(..., 0, n, ...) if (i == 0) { <handle orig_x0> ...; 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(). Signed-off-by: AKASHI Takahiro <takahiro.akashi@linaro.org> Acked-by: Will Deacon <will.deacon@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Cc: Mark Brown <broonie@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
-rw-r--r--arch/arm64/include/asm/syscall.h6
1 files changed, 6 insertions, 0 deletions
diff --git a/arch/arm64/include/asm/syscall.h b/arch/arm64/include/asm/syscall.h
index 89c047f9a97..70ba9d4ee97 100644
--- a/arch/arm64/include/asm/syscall.h
+++ b/arch/arm64/include/asm/syscall.h
@@ -59,6 +59,9 @@ 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;
@@ -82,6 +85,9 @@ 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);