Currently this operation requires the global CAP_SYS_RESOURCE.
It's required, because a task can exceed limits (RLIMIT_DATA,
RLIMIT_STACK).
So let's allow task to change these parameters if a proper limit is
unlimited.
When we restore a task we need to set up text, data and data heap sizes
from userspace to the values a task had at checkpoint time.
Currently we can not restore these parameters, if a task lives in
a non-root user name space, because it has no capabilities in the
parent namespace.
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Oleg Nesterov <o...@redhat.com>
Cc: Al Viro <v...@zeniv.linux.org.uk>
Cc: Kees Cook <keesc...@chromium.org>
Cc: "Eric W. Biederman" <ebied...@xmission.com>
Cc: Stephen Rothwell <s...@canb.auug.org.au>
Cc: Pavel Emelyanov <xe...@parallels.com>
Cc: Aditya Kali <adityak...@google.com>
Signed-off-by: Andrey Vagin <ava...@openvz.org>
---
kernel/sys.c | 19 +++++++++++++++++--
1 file changed, 17 insertions(+), 2 deletions(-)
diff --git a/kernel/sys.c b/kernel/sys.c
index c0a58be..939370c 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -1701,8 +1701,23 @@ static int prctl_set_mm(int opt, unsigned long addr,
if (arg5 || (arg4 && opt != PR_SET_MM_AUXV))
return -EINVAL;
- if (!capable(CAP_SYS_RESOURCE))
- return -EPERM;
+ if (!capable(CAP_SYS_RESOURCE)) {
+ switch (opt) {
+ case PR_SET_MM_START_DATA:
+ case PR_SET_MM_END_DATA:
+ case PR_SET_MM_START_BRK:
+ case PR_SET_MM_BRK:
+ if (rlim < RLIM_INFINITY)
+ return -EPERM;
+ break;
+ case PR_SET_MM_START_STACK:
+ if (rlimit(RLIMIT_STACK) < RLIM_INFINITY)
+ return -EPERM;
+ break;
+ default:
+ return -EPERM;
+ }
+ }
if (opt == PR_SET_MM_EXE_FILE)
return prctl_set_mm_exe_file(mm, (unsigned int)addr);
--
1.8.5.3
--
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