From ac42af98f74d6502e8ab3f8f7e014f3a1580e323 Mon Sep 17 00:00:00 2001 From: Timothy E Baldwin Date: Fri, 27 May 2016 15:18:39 +0100 Subject: linux-user: Block signals during sigaction() handling Block signals while emulating sigaction. This is a non-interruptible syscall, and using block_signals() avoids races where the host signal handler is invoked and tries to examine the signal handler data structures while we are updating them. Signed-off-by: Timothy Edward Baldwin Message-id: 1441497448-32489-29-git-send-email-T.E.Baldwin99@members.leeds.ac.uk [PMM: expanded commit message] Reviewed-by: Peter Maydell Signed-off-by: Peter Maydell --- linux-user/signal.c | 12 +++++++++--- 1 file changed, 9 insertions(+), 3 deletions(-) diff --git a/linux-user/signal.c b/linux-user/signal.c index f48902882d..b21d6bf625 100644 --- a/linux-user/signal.c +++ b/linux-user/signal.c @@ -640,7 +640,7 @@ out: return ret; } -/* do_sigaction() return host values and errnos */ +/* do_sigaction() return target values and host errnos */ int do_sigaction(int sig, const struct target_sigaction *act, struct target_sigaction *oact) { @@ -649,8 +649,14 @@ int do_sigaction(int sig, const struct target_sigaction *act, int host_sig; int ret = 0; - if (sig < 1 || sig > TARGET_NSIG || sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) - return -EINVAL; + if (sig < 1 || sig > TARGET_NSIG || sig == TARGET_SIGKILL || sig == TARGET_SIGSTOP) { + return -TARGET_EINVAL; + } + + if (block_signals()) { + return -TARGET_ERESTARTSYS; + } + k = &sigact_table[sig - 1]; if (oact) { __put_user(k->_sa_handler, &oact->_sa_handler); -- cgit v1.2.3