From: Dave Martin Date: Mon, 27 Mar 2017 14:10:54 +0000 (+0100) Subject: h8300/ptrace: Fix incorrect register transfer count X-Git-Tag: v4.9.20~9 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=616fe993f410c589cd928dfb015ccaf9c931dcc1;p=platform%2Fkernel%2Flinux-amlogic.git h8300/ptrace: Fix incorrect register transfer count commit 502585c7555083d4a949c08350306b9ec196779e upstream. regs_set() and regs_get() are vulnerable to an off-by-1 buffer overrun if CONFIG_CPU_H8S is set, since this adds an extra entry to register_offset[] but not to user_regs_struct. So, iterate over user_regs_struct based on its actual size, not based on the length of register_offset[]. Signed-off-by: Dave Martin Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- diff --git a/arch/h8300/kernel/ptrace.c b/arch/h8300/kernel/ptrace.c index 9207554..0dc1c8f 100644 --- a/arch/h8300/kernel/ptrace.c +++ b/arch/h8300/kernel/ptrace.c @@ -95,7 +95,8 @@ static int regs_get(struct task_struct *target, long *reg = (long *)®s; /* build user regs in buffer */ - for (r = 0; r < ARRAY_SIZE(register_offset); r++) + BUILD_BUG_ON(sizeof(regs) % sizeof(long) != 0); + for (r = 0; r < sizeof(regs) / sizeof(long); r++) *reg++ = h8300_get_reg(target, r); return user_regset_copyout(&pos, &count, &kbuf, &ubuf, @@ -113,7 +114,8 @@ static int regs_set(struct task_struct *target, long *reg; /* build user regs in buffer */ - for (reg = (long *)®s, r = 0; r < ARRAY_SIZE(register_offset); r++) + BUILD_BUG_ON(sizeof(regs) % sizeof(long) != 0); + for (reg = (long *)®s, r = 0; r < sizeof(regs) / sizeof(long); r++) *reg++ = h8300_get_reg(target, r); ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, @@ -122,7 +124,7 @@ static int regs_set(struct task_struct *target, return ret; /* write back to pt_regs */ - for (reg = (long *)®s, r = 0; r < ARRAY_SIZE(register_offset); r++) + for (reg = (long *)®s, r = 0; r < sizeof(regs) / sizeof(long); r++) h8300_put_reg(target, r, *reg++); return 0; }