The patch titled
capabilities: simplify bound checks for copy_from_user()
has been added to the -mm tree. Its filename is
capabilities-simplify-bound-checks-for-copy_from_user.patch
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------------------------------------------------------
Subject: capabilities: simplify bound checks for copy_from_user()
From: Arjan van de Ven <arjan@xxxxxxxxxxxxx>
The capabilities syscall has a copy_from_user() call where gcc currently
cannot prove to itself that the copy is always within bounds.
This patch adds a very explicity bound check to prove to gcc that this
copy_from_user cannot overflow its destination buffer.
Signed-off-by: Arjan van de Ven <arjan@xxxxxxxxxxxxxxx>
Acked-by: James Morris <jmorris@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
diff -puN kernel/capability.c~capabilities-simplify-bound-checks-for-copy_from_user kernel/capability.c
--- a/kernel/capability.c~capabilities-simplify-bound-checks-for-copy_from_user
+++ a/kernel/capability.c
@@ -238,7 +238,7 @@ SYSCALL_DEFINE2(capget, cap_user_header_
SYSCALL_DEFINE2(capset, cap_user_header_t, header, const cap_user_data_t, data)
{
struct __user_cap_data_struct kdata[_KERNEL_CAPABILITY_U32S];
- unsigned i, tocopy;
+ unsigned i, tocopy, copybytes;
kernel_cap_t inheritable, permitted, effective;
struct cred *new;
int ret;
@@ -255,8 +255,11 @@ SYSCALL_DEFINE2(capset, cap_user_header_
if (pid != 0 && pid != task_pid_vnr(current))
return -EPERM;
- if (copy_from_user(&kdata, data,
- tocopy * sizeof(struct __user_cap_data_struct)))
+ copybytes = tocopy * sizeof(struct __user_cap_data_struct);
+ if (copybytes > sizeof(kdata))
+ return -EFAULT;
+
+ if (copy_from_user(&kdata, data, copybytes))
return -EFAULT;
for (i = 0; i < tocopy; i++) {
_
Patches currently in -mm which might be from arjan@xxxxxxxxxxxxx are
linux-next.patch
capabilities-simplify-bound-checks-for-copy_from_user.patch
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