Add a max errno value.
This is not strictly needed but should improve reliability.
Signed-off-by: Mickaël Salaün <mic@xxxxxxxxxxx>
Cc: Arnd Bergmann <arnd@xxxxxxxx>
Cc: Serge E. Hallyn <serge@xxxxxxxxxx>
Cc: James Morris <james.l.morris@xxxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
---
include/uapi/asm-generic/errno-base.h | 1 +
security/landlock/lsm.c | 6 +++---
2 files changed, 4 insertions(+), 3 deletions(-)
diff --git a/include/uapi/asm-generic/errno-base.h b/include/uapi/asm-generic/errno-base.h
index 65115978510f..43407a403e72 100644
--- a/include/uapi/asm-generic/errno-base.h
+++ b/include/uapi/asm-generic/errno-base.h
@@ -35,5 +35,6 @@
#define EPIPE 32 /* Broken pipe */
#define EDOM 33 /* Math argument out of domain of func */
#define ERANGE 34 /* Math result not representable */
+#define _ERRNO_LAST ERANGE
#endif
diff --git a/security/landlock/lsm.c b/security/landlock/lsm.c
index aa9d4a64826e..322309068066 100644
--- a/security/landlock/lsm.c
+++ b/security/landlock/lsm.c
@@ -11,7 +11,6 @@
#include <asm/current.h>
#include <linux/bpf.h> /* enum bpf_reg_type, struct landlock_data */
#include <linux/cred.h>
-#include <linux/err.h> /* MAX_ERRNO */
#include <linux/filter.h> /* struct bpf_prog, BPF_PROG_RUN() */
#include <linux/kernel.h> /* FIELD_SIZEOF() */
#include <linux/lsm_hooks.h>
@@ -104,8 +103,9 @@ static int landlock_run_prog(__u64 args[6])
}
}
if (!ret) {
- if (cur_ret > MAX_ERRNO)
- ret = MAX_ERRNO;
+ /* check errno to not mess with kernel code */
+ if (cur_ret > _ERRNO_LAST)
+ ret = EPERM;
else
ret = cur_ret;
}
--
2.8.1
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