syscalls/keyctl06: new test for keyring_read() buffer overrun

From: Eric Biggers <[email protected]>

Add a test for a bug which caused the kernel to write past the end of the provided buffer when using KEYCTL_READ to read from a keyring.

---
 runtest/syscalls                            |  1 +
 testcases/kernel/syscalls/.gitignore        |  1 +
 testcases/kernel/syscalls/keyctl/keyctl06.c | 68 +++++++++++++++++++++++++++++
 3 files changed, 70 insertions(+)
 create mode 100644 testcases/kernel/syscalls/keyctl/keyctl06.c

index 2362a231d..67a7362ee 100644
@@ -500,6 +500,7 @@ keyctl02 keyctl02
 keyctl03 keyctl03
 keyctl04 keyctl04
 keyctl05 keyctl05
+keyctl06 keyctl06
 
 kcmp01 kcmp01
 kcmp02 kcmp02

index 930f3f999..1e573d9a4 100644
@@ -462,6 +462,7 @@
 /keyctl/keyctl03
 /keyctl/keyctl04
 /keyctl/keyctl05
+/keyctl/keyctl06
 /kcmp/kcmp01
 /kcmp/kcmp02
 /kcmp/kcmp03

2.14.2.920.gcf0c67979c-goog