diff options
| author | Ed Maste <emaste@FreeBSD.org> | 2026-05-26 13:24:36 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2026-06-08 13:21:33 +0000 |
| commit | eab757f954ed63395aad84624b6b1f96b4195fa0 (patch) | |
| tree | f36efd990c5ef54d39ee8c2449989937b7a1da3d | |
| parent | 0e8cc8d8a49f2393fcbc836171f0a85a0e4bd92c (diff) | |
sigqueue: In capability mode, only allow signalling self
This is copied from the check in kern_kill.
Approved by: so
Security: FreeBSD-SA-26:28.capsicum
Security: CVE-2026-45259
Reviewed by: markj, oshogbo
Sponsored by: The FreeBSD Foundation
Differential Revision: https://reviews.freebsd.org/D57244
(cherry picked from commit b9d16b7fd2fa6bc4b3e8364804cbdc1b76ebe8a5)
(cherry picked from commit defd9b86ef995ce70363eae9b323d616bda865be)
(cherry picked from commit d11ff01b3aec336128e6babbff7a421fbce82015)
| -rw-r--r-- | contrib/capsicum-test/capmode.cc | 12 | ||||
| -rw-r--r-- | sys/kern/kern_sig.c | 10 |
2 files changed, 19 insertions, 3 deletions
diff --git a/contrib/capsicum-test/capmode.cc b/contrib/capsicum-test/capmode.cc index f32d9e038744..12921bb53c72 100644 --- a/contrib/capsicum-test/capmode.cc +++ b/contrib/capsicum-test/capmode.cc @@ -747,8 +747,8 @@ FORK_TEST(Capmode, NewThread) { close(thread_pipe[1]); } -static volatile sig_atomic_t had_signal = 0; -static void handle_signal(int) { had_signal = 1; } +static volatile sig_atomic_t signal_cnt = 0; +static void handle_signal(int) { signal_cnt++; } FORK_TEST(Capmode, SelfKill) { pid_t me = getpid(); @@ -766,7 +766,13 @@ FORK_TEST(Capmode, SelfKill) { // Can only kill(2) to own pid. EXPECT_CAPMODE(kill(child, SIGUSR1)); EXPECT_OK(kill(me, SIGUSR1)); - EXPECT_EQ(1, had_signal); + EXPECT_EQ(1, signal_cnt); + + union sigval sv; + sv.sival_int = 0x1234; + EXPECT_CAPMODE(sigqueue(child, SIGUSR1, sv)); + EXPECT_OK(sigqueue(me, SIGUSR1, sv)); + EXPECT_EQ(2, signal_cnt); signal(SIGUSR1, original); } diff --git a/sys/kern/kern_sig.c b/sys/kern/kern_sig.c index 91361d680809..7f399586f639 100644 --- a/sys/kern/kern_sig.c +++ b/sys/kern/kern_sig.c @@ -2047,6 +2047,16 @@ kern_sigqueue(struct thread *td, pid_t pid, int signumf, union sigval *value) if (pid <= 0) return (EINVAL); + /* + * A process in capability mode can send signals only to itself. + */ + if (pid != td->td_proc->p_pid) { + if (CAP_TRACING(td)) + ktrcapfail(CAPFAIL_SIGNAL, &signum); + if (IN_CAPABILITY_MODE(td)) + return (ECAPMODE); + } + if ((signumf & __SIGQUEUE_TID) == 0) { if ((p = pfind_any(pid)) == NULL) return (ESRCH); |