From 43e1e809a5b7f9bdc65cfd0bdf45675dc7d40fb4 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Thu, 17 Dec 2009 07:04:56 -0800 Subject: x86/ptrace: make genregs[32]_get/set more robust commit 04a1e62c2cec820501f93526ad1e46073b802dc4 upstream. The loop condition is fragile: we compare an unsigned value to zero, and then decrement it by something larger than one in the loop. All the callers should be passing in appropriately aligned buffer lengths, but it's better to just not rely on it, and have some appropriate defensive loop limits. Acked-by: Roland McGrath Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- arch/x86/kernel/ptrace.c | 16 ++++++++-------- 1 file changed, 8 insertions(+), 8 deletions(-) diff --git a/arch/x86/kernel/ptrace.c b/arch/x86/kernel/ptrace.c index 12fe58938c6..a0db19c8b0d 100644 --- a/arch/x86/kernel/ptrace.c +++ b/arch/x86/kernel/ptrace.c @@ -416,14 +416,14 @@ static int genregs_get(struct task_struct *target, { if (kbuf) { unsigned long *k = kbuf; - while (count > 0) { + while (count >= sizeof(*k)) { *k++ = getreg(target, pos); count -= sizeof(*k); pos += sizeof(*k); } } else { unsigned long __user *u = ubuf; - while (count > 0) { + while (count >= sizeof(*u)) { if (__put_user(getreg(target, pos), u++)) return -EFAULT; count -= sizeof(*u); @@ -442,14 +442,14 @@ static int genregs_set(struct task_struct *target, int ret = 0; if (kbuf) { const unsigned long *k = kbuf; - while (count > 0 && !ret) { + while (count >= sizeof(*k) && !ret) { ret = putreg(target, pos, *k++); count -= sizeof(*k); pos += sizeof(*k); } } else { const unsigned long __user *u = ubuf; - while (count > 0 && !ret) { + while (count >= sizeof(*u) && !ret) { unsigned long word; ret = __get_user(word, u++); if (ret) @@ -1159,14 +1159,14 @@ static int genregs32_get(struct task_struct *target, { if (kbuf) { compat_ulong_t *k = kbuf; - while (count > 0) { + while (count >= sizeof(*k)) { getreg32(target, pos, k++); count -= sizeof(*k); pos += sizeof(*k); } } else { compat_ulong_t __user *u = ubuf; - while (count > 0) { + while (count >= sizeof(*u)) { compat_ulong_t word; getreg32(target, pos, &word); if (__put_user(word, u++)) @@ -1187,14 +1187,14 @@ static int genregs32_set(struct task_struct *target, int ret = 0; if (kbuf) { const compat_ulong_t *k = kbuf; - while (count > 0 && !ret) { + while (count >= sizeof(*k) && !ret) { ret = putreg32(target, pos, *k++); count -= sizeof(*k); pos += sizeof(*k); } } else { const compat_ulong_t __user *u = ubuf; - while (count > 0 && !ret) { + while (count >= sizeof(*u) && !ret) { compat_ulong_t word; ret = __get_user(word, u++); if (ret) -- cgit v1.2.3-18-g5258