| Message ID | f96ed94dc57ea810b738c4e02263e08c2c8781b6.1580801787.git.christophe.leroy@c-s.fr (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | [1/4] uaccess: Add user_read_access_begin/end and user_write_access_begin/end | expand |
| Context | Check | Description |
|---|---|---|
| snowpatch_ozlabs/apply_patch | success | Successfully applied on branch powerpc/merge (7e7c42aa339cb92ad758bd0b5e7a299fecf9f9ce) |
| snowpatch_ozlabs/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 14 lines checked |
| snowpatch_ozlabs/needsstable | success | Patch has no Fixes tags |
diff --git a/include/linux/uaccess.h b/include/linux/uaccess.h index 67f016010aad..9861c89f93be 100644 --- a/include/linux/uaccess.h +++ b/include/linux/uaccess.h @@ -378,6 +378,14 @@ extern long strnlen_unsafe_user(const void __user *unsafe_addr, long count); static inline unsigned long user_access_save(void) { return 0UL; } static inline void user_access_restore(unsigned long flags) { } #endif +#ifndef user_write_access_begin +#define user_write_access_begin user_access_begin +#define user_write_access_end user_access_end +#endif +#ifndef user_read_access_begin +#define user_read_access_begin user_access_begin +#define user_read_access_end user_access_end +#endif #ifdef CONFIG_HARDENED_USERCOPY void usercopy_warn(const char *name, const char *detail, bool to_user,
Some architectures like powerpc64 have the capability to separate read access and write access protection. For get_user() and copy_from_user(), powerpc64 only open read access. For put_user() and copy_to_user(), powerpc64 only open write access. But when using unsafe_get_user() or unsafe_put_user(), user_access_begin open both read and write. In order to avoid any risk based of hacking some variable parameters passed to user_access_begin/end that would allow hacking and leaving user access open or opening too much, it is preferable to use dedicated static functions that can't be overridden. Add a user_read_access_begin and user_read_access_end to only open read access. Add a user_write_access_begin and user_write_access_end to only open write access. By default, when undefined, those new access helpers default on the existing user_access_begin and user_access_end. Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr> --- include/linux/uaccess.h | 8 ++++++++ 1 file changed, 8 insertions(+)