[CRIU] [PATCHv2] files-reg: fix /proc/<pid>/* ownership for linkat restore

[Dmitry Safonov]

After linkat_hard with setfsuid permissions of files in
/proc/<pid>/* changes to root because of pid_getattr @ fs/proc/base.c
will fail to check has_pid_permissions() in ptrace_may_access()
Fix it with PR_SET_DUMPABLE.

Cc: Andrew Vagin <avagin at virtuozzo.com>
Signed-off-by: Dmitry Safonov <dsafonov at odin.com>
---
 files-reg.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/files-reg.c b/files-reg.c
index 425dc04..bce9cae 100644
--- a/files-reg.c
+++ b/files-reg.c
@@ -6,6 +6,7 @@
 #include <sys/mman.h>
 #include <sys/types.h>
 #include <sys/stat.h>
+#include <sys/prctl.h>
 #include <sys/vfs.h>
 #include <ctype.h>
 
@@ -1100,6 +1101,8 @@ static int linkat_hard(int odir, char *opath, int ndir, char *npath, uid_t owner
 			 */
 	}
 	errno = errno_save;
+	if (prctl(PR_SET_DUMPABLE, 1, 0))
+		pr_perror("Cant set the dumpable flag");
 
 	return ret;
 }
-- 
2.6.3