Messages in this thread Patch in this message | | | Date | Sun, 25 Aug 2019 16:18:56 -0700 | From | Kees Cook <> | Subject | [PATCH] uaccess: Disallow > INT_MAX copy sizes |
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As we've done with VFS, string operations, etc, reject usercopy sizes larger than INT_MAX, which would be nice to have for catching bugs related to size calculation overflows[1].
This adds 10 bytes to x86_64 defconfig text and 1980 bytes to the data section:
text data bss dec hex filename 19691167 5134320 1646664 26472151 193eed7 vmlinux.before 19691177 5136300 1646664 26474141 193f69d vmlinux.after
[1] https://marc.info/?l=linux-s390&m=156631939010493&w=2
Suggested-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Kees Cook <keescook@chromium.org> --- include/linux/thread_info.h | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/include/linux/thread_info.h b/include/linux/thread_info.h index 659a4400517b..e93e249a4e9b 100644 --- a/include/linux/thread_info.h +++ b/include/linux/thread_info.h @@ -147,6 +147,8 @@ check_copy_size(const void *addr, size_t bytes, bool is_source) __bad_copy_to(); return false; } + if (WARN_ON_ONCE(bytes > INT_MAX)) + return false; check_object_size(addr, bytes, is_source); return true; } -- 2.17.1
-- Kees Cook
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