Fix a bug in sigaction

The bug would allow the user to block non-blockable signals (SIGKILL and SIGSTOP) using sigaction syscall. This commit fixes this bug.
2020-07-17 17:10:55 +00:00 · 2020-07-17 17:10:55 +00:00 · 8c7b59ad17
commit 8c7b59ad17
parent 1f30d75713
1 changed files with 8 additions and 1 deletions
--- a/src/libos/src/signal/sig_action.rs
+++ b/src/libos/src/signal/sig_action.rs
@ -31,7 +31,14 @@ impl SigAction {
                handler_addr: sa_c.handler as usize,
                flags: SigActionFlags::from_u32(sa_c.flags)?,
                restorer_addr: sa_c.restorer as usize,
-                mask: SigSet::from_c(sa_c.mask),
+                mask: {
+                    let mut mask = SigSet::from_c(sa_c.mask);
+                    // According to man pages, "it is not possible to block SIGKILL or SIGSTOP.
+                    // Attempts to do so are silently ignored."
+                    mask -= SIGKILL;
+                    mask -= SIGSTOP;
+                    mask
+                },
            },
        };
        Ok(sa)