diff options
| author | Willy Tarreau <w@1wt.eu> | 2018-05-11 08:11:44 +0200 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2018-05-17 09:27:47 -0700 |
| commit | 7f7ccc2ccc2e70c6054685f5e3522efa81556830 (patch) | |
| tree | 7309cb80e03910053c21d5b003ed1d6b2dcacc16 /include/linux/mm.h | |
| parent | e6506eb241871d68647c53cb6d0a16299550ae97 (diff) | |
proc: do not access cmdline nor environ from file-backed areas
proc_pid_cmdline_read() and environ_read() directly access the target
process' VM to retrieve the command line and environment. If this
process remaps these areas onto a file via mmap(), the requesting
process may experience various issues such as extra delays if the
underlying device is slow to respond.
Let's simply refuse to access file-backed areas in these functions.
For this we add a new FOLL_ANON gup flag that is passed to all calls
to access_remote_vm(). The code already takes care of such failures
(including unmapped areas). Accesses via /proc/pid/mem were not
changed though.
This was assigned CVE-2018-1120.
Note for stable backports: the patch may apply to kernels prior to 4.11
but silently miss one location; it must be checked that no call to
access_remote_vm() keeps zero as the last argument.
Reported-by: Qualys Security Advisory <qsa@qualys.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: stable@vger.kernel.org
Signed-off-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mm.h')
| -rw-r--r-- | include/linux/mm.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 1ac1f06a4be6..c080af584ddd 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -2493,6 +2493,7 @@ static inline struct page *follow_page(struct vm_area_struct *vma, #define FOLL_MLOCK 0x1000 /* lock present pages */ #define FOLL_REMOTE 0x2000 /* we are working on non-current tsk/mm */ #define FOLL_COW 0x4000 /* internal GUP flag */ +#define FOLL_ANON 0x8000 /* don't do file mappings */ static inline int vm_fault_to_errno(int vm_fault, int foll_flags) { |