diff options
| author | Ed Maste <emaste@FreeBSD.org> | 2026-05-26 13:24:36 +0000 |
|---|---|---|
| committer | Mark Johnston <markj@FreeBSD.org> | 2026-06-08 15:39:32 +0000 |
| commit | 77ee83d12625fea81a278d53cc621c610c353955 (patch) | |
| tree | a6e463cc809ac4e2d8ba3a3fcbca86100a082dfa | |
| parent | bda153dc04b4ddb667856874c083bd117fc0b9a1 (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)
| -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 5ff025290211..d2eb1e8633a8 100644 --- a/contrib/capsicum-test/capmode.cc +++ b/contrib/capsicum-test/capmode.cc @@ -746,8 +746,8 @@ 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(); @@ -765,7 +765,13 @@ 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 1eac5cc2993f..40da0a79b810 100644 --- a/sys/kern/kern_sig.c +++ b/sys/kern/kern_sig.c @@ -2037,6 +2037,16 @@ 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); |