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authorIngo Molnar <mingo@kernel.org>2017-09-23 15:59:52 +0300
committerIngo Molnar <mingo@kernel.org>2017-09-24 14:04:32 +0300
commit6ff15f8db7eaf29ef5ead6afbec9b25485fe8703 (patch)
tree63194abd2d85169c91cb6eed9fe45290491b76f0 /arch/x86/kernel/fpu
parent56583c9a1400fe1935edd55b24b4fbbc779b59cb (diff)
downloadlinux-6ff15f8db7eaf29ef5ead6afbec9b25485fe8703.tar.xz
x86/fpu: Change 'size_total' parameter to unsigned and standardize the size checks in copy_xstate_to_*()
'size_total' is derived from an unsigned input parameter - and then converted to 'int' and checked for negative ranges: if (size_total < 0 || offset < size_total) { This conversion and the checks are unnecessary obfuscation, reject overly large requested copy sizes outright and simplify the underlying code. Reported-by: Rik van Riel <riel@redhat.com> Cc: Andrew Morton <akpm@linux-foundation.org> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Oleg Nesterov <oleg@redhat.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Link: http://lkml.kernel.org/r/20170923130016.21448-10-mingo@kernel.org Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'arch/x86/kernel/fpu')
-rw-r--r--arch/x86/kernel/fpu/xstate.c32
1 files changed, 15 insertions, 17 deletions
diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index c13083579655..b18c5457065a 100644
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -925,15 +925,11 @@ int arch_set_user_pkey_access(struct task_struct *tsk, int pkey,
* the source data pointer or increment pos, count, kbuf, and ubuf.
*/
static inline int
-__copy_xstate_to_kernel(void *kbuf,
- const void *data,
- unsigned int offset, unsigned int size, int size_total)
+__copy_xstate_to_kernel(void *kbuf, const void *data,
+ unsigned int offset, unsigned int size, unsigned int size_total)
{
- if (!size)
- return 0;
-
- if (size_total < 0 || offset < size_total) {
- unsigned int copy = size_total < 0 ? size : min(size, size_total - offset);
+ if (offset < size_total) {
+ unsigned int copy = min(size, size_total - offset);
memcpy(kbuf + offset, data, copy);
}
@@ -986,12 +982,13 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int of
offset = xstate_offsets[i];
size = xstate_sizes[i];
+ /* The next component has to fit fully into the output buffer: */
+ if (offset + size > size_total)
+ break;
+
ret = __copy_xstate_to_kernel(kbuf, src, offset, size, size_total);
if (ret)
return ret;
-
- if (offset + size >= size_total)
- break;
}
}
@@ -1010,13 +1007,13 @@ int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int of
}
static inline int
-__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int offset, unsigned int size, int size_total)
+__copy_xstate_to_user(void __user *ubuf, const void *data, unsigned int offset, unsigned int size, unsigned int size_total)
{
if (!size)
return 0;
- if (size_total < 0 || offset < size_total) {
- unsigned int copy = size_total < 0 ? size : min(size, size_total - offset);
+ if (offset < size_total) {
+ unsigned int copy = min(size, size_total - offset);
if (__copy_to_user(ubuf + offset, data, copy))
return -EFAULT;
@@ -1069,12 +1066,13 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i
offset = xstate_offsets[i];
size = xstate_sizes[i];
+ /* The next component has to fit fully into the output buffer: */
+ if (offset + size > size_total)
+ break;
+
ret = __copy_xstate_to_user(ubuf, src, offset, size, size_total);
if (ret)
return ret;
-
- if (offset + size >= size_total)
- break;
}
}