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linux-user: fix TARGET_NSIG and _NSIG uses

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Valid signal numbers are between 1 (SIGHUP) and SIGRTMAX.

System includes define _NSIG to SIGRTMAX + 1, but
QEMU (like kernel) defines TARGET_NSIG to TARGET_SIGRTMAX.

Fix all the checks involving the signal range.

Signed-off-by: Laurent Vivier <laurent@vivier.eu>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Tested-by: Taylor Simpson <tsimpson@quicinc.com>
Message-Id: <20200212125658.644558-4-laurent@vivier.eu>
This commit is contained in:
Laurent Vivier 2020-02-12 13:56:57 +01:00
parent 365510fb86
commit 9fcff3a67f
1 changed files with 37 additions and 15 deletions
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52
linux-user/signal.c
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@ -30,6 +30,15 @@ static struct target_sigaction sigact_table[TARGET_NSIG];
static void host_signal_handler(int host_signum, siginfo_t *info, static void host_signal_handler(int host_signum, siginfo_t *info,
void *puc); void *puc);
/*
* System includes define _NSIG as SIGRTMAX + 1,
* but qemu (like the kernel) defines TARGET_NSIG as TARGET_SIGRTMAX
* and the first signal is SIGHUP defined as 1
* Signal number 0 is reserved for use as kill(pid, 0), to test whether
* a process exists without sending it a signal.
*/
QEMU_BUILD_BUG_ON(__SIGRTMAX + 1 != _NSIG);
static uint8_t host_to_target_signal_table[_NSIG] = { static uint8_t host_to_target_signal_table[_NSIG] = {
[SIGHUP] = TARGET_SIGHUP, [SIGHUP] = TARGET_SIGHUP,
[SIGINT] = TARGET_SIGINT, [SIGINT] = TARGET_SIGINT,
@ -67,19 +76,24 @@ static uint8_t host_to_target_signal_table[_NSIG] = {
[SIGSYS] = TARGET_SIGSYS, [SIGSYS] = TARGET_SIGSYS,
/* next signals stay the same */ /* next signals stay the same */
}; };
static uint8_t target_to_host_signal_table[_NSIG];
static uint8_t target_to_host_signal_table[TARGET_NSIG + 1];
/* valid sig is between 1 and _NSIG - 1 */
int host_to_target_signal(int sig) int host_to_target_signal(int sig)
{ {
if (sig < 0 || sig >= _NSIG) if (sig < 1 || sig >= _NSIG) {
return sig; return sig;
}
return host_to_target_signal_table[sig]; return host_to_target_signal_table[sig];
} }
/* valid sig is between 1 and TARGET_NSIG */
int target_to_host_signal(int sig) int target_to_host_signal(int sig)
{ {
if (sig < 0 || sig >= _NSIG) if (sig < 1 || sig > TARGET_NSIG) {
return sig; return sig;
}
return target_to_host_signal_table[sig]; return target_to_host_signal_table[sig];
} }
@ -100,11 +114,15 @@ static inline int target_sigismember(const target_sigset_t *set, int signum)
void host_to_target_sigset_internal(target_sigset_t *d, void host_to_target_sigset_internal(target_sigset_t *d,
const sigset_t *s) const sigset_t *s)
{ {
int i; int host_sig, target_sig;
target_sigemptyset(d); target_sigemptyset(d);
for (i = 1; i <= TARGET_NSIG; i++) { for (host_sig = 1; host_sig < _NSIG; host_sig++) {
if (sigismember(s, i)) { target_sig = host_to_target_signal(host_sig);
target_sigaddset(d, host_to_target_signal(i)); if (target_sig < 1 || target_sig > TARGET_NSIG) {
continue;
}
if (sigismember(s, host_sig)) {
target_sigaddset(d, target_sig);
} }
} }
} }
@ -122,11 +140,15 @@ void host_to_target_sigset(target_sigset_t *d, const sigset_t *s)
void target_to_host_sigset_internal(sigset_t *d, void target_to_host_sigset_internal(sigset_t *d,
const target_sigset_t *s) const target_sigset_t *s)
{ {
int i; int host_sig, target_sig;
sigemptyset(d); sigemptyset(d);
for (i = 1; i <= TARGET_NSIG; i++) { for (target_sig = 1; target_sig <= TARGET_NSIG; target_sig++) {
if (target_sigismember(s, i)) { host_sig = target_to_host_signal(target_sig);
sigaddset(d, target_to_host_signal(i)); if (host_sig < 1 || host_sig >= _NSIG) {
continue;
}
if (target_sigismember(s, target_sig)) {
sigaddset(d, host_sig);
} }
} }
} }
@ -492,10 +514,10 @@ static void signal_table_init(void)
if (host_to_target_signal_table[host_sig] == 0) { if (host_to_target_signal_table[host_sig] == 0) {
host_to_target_signal_table[host_sig] = host_sig; host_to_target_signal_table[host_sig] = host_sig;
} }
}
for (host_sig = 1; host_sig < _NSIG; host_sig++) {
target_sig = host_to_target_signal_table[host_sig]; target_sig = host_to_target_signal_table[host_sig];
target_to_host_signal_table[target_sig] = host_sig; if (target_sig <= TARGET_NSIG) {
target_to_host_signal_table[target_sig] = host_sig;
}
} }
} }
@ -518,7 +540,7 @@ void signal_init(void)
act.sa_sigaction = host_signal_handler; act.sa_sigaction = host_signal_handler;
for(i = 1; i <= TARGET_NSIG; i++) { for(i = 1; i <= TARGET_NSIG; i++) {
#ifdef TARGET_GPROF #ifdef TARGET_GPROF
if (i == SIGPROF) { if (i == TARGET_SIGPROF) {
continue; continue;
} }
#endif #endif