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[3.8.y.z,extended,stable] Patch "ARM: 7851/1: check for number of arguments in" has been added to staging queue

Message ID 1383069287-10502-1-git-send-email-kamal@canonical.com
State New
Headers show

Commit Message

Kamal Mostafa Oct. 29, 2013, 5:54 p.m. UTC 
This is a note to let you know that I have just added a patch titled

    ARM: 7851/1: check for number of arguments in

to the linux-3.8.y-queue branch of the 3.8.y.z extended stable tree 
which can be found at:

 http://kernel.ubuntu.com/git?p=ubuntu/linux.git;a=shortlog;h=refs/heads/linux-3.8.y-queue

This patch is scheduled to be released in version 3.8.13.12.

If you, or anyone else, feels it should not be added to this tree, please 
reply to this email.

For more information about the 3.8.y.z tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable

Thanks.
-Kamal

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From 3aac083f168a9a61c48710ac254b6c2b7c722ea6 Mon Sep 17 00:00:00 2001
From: AKASHI Takahiro <takahiro.akashi@linaro.org>
Date: Wed, 9 Oct 2013 15:58:29 +0100
Subject: 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: Kamal Mostafa <kamal@canonical.com>
---
 arch/arm/include/asm/syscall.h | 6 ++++++
 1 file changed, 6 insertions(+)

--
1.8.1.2
diff mbox

Patch

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);