Merge remote-tracking branch 'remotes/vivier2/tags/linux-user-for-5.2-pull-request' into staging

Add clock_getres_time64, timer_gettime64, timer_settime64,
    timerfd_gettime64, timerfd_settime64
Some fixes (page protection, print_fdset, timerspec, itimerspec)

# gpg: Signature made Sun 23 Aug 2020 15:58:53 BST
# gpg:                using RSA key CD2F75DDC8E3A4DC2E4F5173F30C38BD3F2FBE3C
# gpg:                issuer "laurent@vivier.eu"
# gpg: Good signature from "Laurent Vivier <lvivier@redhat.com>" [full]
# gpg:                 aka "Laurent Vivier <laurent@vivier.eu>" [full]
# gpg:                 aka "Laurent Vivier (Red Hat) <lvivier@redhat.com>" [full]
# Primary key fingerprint: CD2F 75DD C8E3 A4DC 2E4F  5173 F30C 38BD 3F2F BE3C

* remotes/vivier2/tags/linux-user-for-5.2-pull-request:
  linux-user: Fix 'utimensat()' implementation
  linux-user: Add support for a group of 2038 safe syscalls
  linux-user: Modify 'target_to_host/host_to_target_itimerspec()'
  linux-user: Adjust guest page protection for the host
  linux-user: Validate mmap/mprotect prot value
  linux-user: Fix "print_fdset()" in "strace.c" to not print ", " after last value

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

4 files changed, 250 insertions, 63 deletions

diff --git a/linux-user/mmap.c b/linux-user/mmap.c
index 0019447892..f261563420 100644
--- a/linux-user/mmap.c
+++ b/linux-user/mmap.c
@@ -59,64 +59,100 @@ void mmap_fork_end(int child)
         pthread_mutex_unlock(&mmap_mutex);
 }
 
+/*
+ * Validate target prot bitmask.
+ * Return the prot bitmask for the host in *HOST_PROT.
+ * Return 0 if the target prot bitmask is invalid, otherwise
+ * the internal qemu page_flags (which will include PAGE_VALID).
+ */
+static int validate_prot_to_pageflags(int *host_prot, int prot)
+{
+    int valid = PROT_READ | PROT_WRITE | PROT_EXEC | TARGET_PROT_SEM;
+    int page_flags = (prot & PAGE_BITS) | PAGE_VALID;
+
+    /*
+     * For the host, we need not pass anything except read/write/exec.
+     * While PROT_SEM is allowed by all hosts, it is also ignored, so
+     * don't bother transforming guest bit to host bit.  Any other
+     * target-specific prot bits will not be understood by the host
+     * and will need to be encoded into page_flags for qemu emulation.
+     *
+     * Pages that are executable by the guest will never be executed
+     * by the host, but the host will need to be able to read them.
+     */
+    *host_prot = (prot & (PROT_READ | PROT_WRITE))
+               | (prot & PROT_EXEC ? PROT_READ : 0);
+
+    return prot & ~valid ? 0 : page_flags;
+}
+
 /* NOTE: all the constants are the HOST ones, but addresses are target. */
-int target_mprotect(abi_ulong start, abi_ulong len, int prot)
+int target_mprotect(abi_ulong start, abi_ulong len, int target_prot)
 {
     abi_ulong end, host_start, host_end, addr;
-    int prot1, ret;
+    int prot1, ret, page_flags, host_prot;
 
-    trace_target_mprotect(start, len, prot);
+    trace_target_mprotect(start, len, target_prot);
 
-    if ((start & ~TARGET_PAGE_MASK) != 0)
+    if ((start & ~TARGET_PAGE_MASK) != 0) {
         return -TARGET_EINVAL;
+    }
+    page_flags = validate_prot_to_pageflags(&host_prot, target_prot);
+    if (!page_flags) {
+        return -TARGET_EINVAL;
+    }
     len = TARGET_PAGE_ALIGN(len);
     end = start + len;
     if (!guest_range_valid(start, len)) {
         return -TARGET_ENOMEM;
     }
-    prot &= PROT_READ | PROT_WRITE | PROT_EXEC;
-    if (len == 0)
+    if (len == 0) {
         return 0;
+    }
 
     mmap_lock();
     host_start = start & qemu_host_page_mask;
     host_end = HOST_PAGE_ALIGN(end);
     if (start > host_start) {
         /* handle host page containing start */
-        prot1 = prot;
-        for(addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
+        prot1 = host_prot;
+        for (addr = host_start; addr < start; addr += TARGET_PAGE_SIZE) {
             prot1 |= page_get_flags(addr);
         }
         if (host_end == host_start + qemu_host_page_size) {
-            for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
+            for (addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
                 prot1 |= page_get_flags(addr);
             }
             end = host_end;
         }
-        ret = mprotect(g2h(host_start), qemu_host_page_size, prot1 & PAGE_BITS);
-        if (ret != 0)
+        ret = mprotect(g2h(host_start), qemu_host_page_size,
+                       prot1 & PAGE_BITS);
+        if (ret != 0) {
             goto error;
+        }
         host_start += qemu_host_page_size;
     }
     if (end < host_end) {
-        prot1 = prot;
-        for(addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
+        prot1 = host_prot;
+        for (addr = end; addr < host_end; addr += TARGET_PAGE_SIZE) {
             prot1 |= page_get_flags(addr);
         }
-        ret = mprotect(g2h(host_end - qemu_host_page_size), qemu_host_page_size,
-                       prot1 & PAGE_BITS);
-        if (ret != 0)
+        ret = mprotect(g2h(host_end - qemu_host_page_size),
+                       qemu_host_page_size, prot1 & PAGE_BITS);
+        if (ret != 0) {
             goto error;
+        }
         host_end -= qemu_host_page_size;
     }
 
     /* handle the pages in the middle */
     if (host_start < host_end) {
-        ret = mprotect(g2h(host_start), host_end - host_start, prot);
-        if (ret != 0)
+        ret = mprotect(g2h(host_start), host_end - host_start, host_prot);
+        if (ret != 0) {
             goto error;
+        }
     }
-    page_set_flags(start, start + len, prot | PAGE_VALID);
+    page_set_flags(start, start + len, page_flags);
     mmap_unlock();
     return 0;
 error:
@@ -360,19 +396,26 @@ abi_ulong mmap_find_vma(abi_ulong start, abi_ulong size, abi_ulong align)
 }
 
 /* NOTE: all the constants are the HOST ones */
-abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
+abi_long target_mmap(abi_ulong start, abi_ulong len, int target_prot,
                      int flags, int fd, abi_ulong offset)
 {
     abi_ulong ret, end, real_start, real_end, retaddr, host_offset, host_len;
+    int page_flags, host_prot;
 
     mmap_lock();
-    trace_target_mmap(start, len, prot, flags, fd, offset);
+    trace_target_mmap(start, len, target_prot, flags, fd, offset);
 
     if (!len) {
         errno = EINVAL;
         goto fail;
     }
 
+    page_flags = validate_prot_to_pageflags(&host_prot, target_prot);
+    if (!page_flags) {
+        errno = EINVAL;
+        goto fail;
+    }
+
     /* Also check for overflows... */
     len = TARGET_PAGE_ALIGN(len);
     if (!len) {
@@ -438,14 +481,15 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
         /* Note: we prefer to control the mapping address. It is
            especially important if qemu_host_page_size >
            qemu_real_host_page_size */
-        p = mmap(g2h(start), host_len, prot,
+        p = mmap(g2h(start), host_len, host_prot,
                  flags | MAP_FIXED | MAP_ANONYMOUS, -1, 0);
-        if (p == MAP_FAILED)
+        if (p == MAP_FAILED) {
             goto fail;
+        }
         /* update start so that it points to the file position at 'offset' */
         host_start = (unsigned long)p;
         if (!(flags & MAP_ANONYMOUS)) {
-            p = mmap(g2h(start), len, prot,
+            p = mmap(g2h(start), len, host_prot,
                      flags | MAP_FIXED, fd, host_offset);
             if (p == MAP_FAILED) {
                 munmap(g2h(start), host_len);
@@ -479,19 +523,19 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
             /* msync() won't work here, so we return an error if write is
                possible while it is a shared mapping */
             if ((flags & MAP_TYPE) == MAP_SHARED &&
-                (prot & PROT_WRITE)) {
+                (host_prot & PROT_WRITE)) {
                 errno = EINVAL;
                 goto fail;
             }
-            retaddr = target_mmap(start, len, prot | PROT_WRITE,
+            retaddr = target_mmap(start, len, target_prot | PROT_WRITE,
                                   MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS,
                                   -1, 0);
             if (retaddr == -1)
                 goto fail;
             if (pread(fd, g2h(start), len, offset) == -1)
                 goto fail;
-            if (!(prot & PROT_WRITE)) {
-                ret = target_mprotect(start, len, prot);
+            if (!(host_prot & PROT_WRITE)) {
+                ret = target_mprotect(start, len, target_prot);
                 assert(ret == 0);
             }
             goto the_end;
@@ -502,13 +546,13 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
             if (real_end == real_start + qemu_host_page_size) {
                 /* one single host page */
                 ret = mmap_frag(real_start, start, end,
-                                prot, flags, fd, offset);
+                                host_prot, flags, fd, offset);
                 if (ret == -1)
                     goto fail;
                 goto the_end1;
             }
             ret = mmap_frag(real_start, start, real_start + qemu_host_page_size,
-                            prot, flags, fd, offset);
+                            host_prot, flags, fd, offset);
             if (ret == -1)
                 goto fail;
             real_start += qemu_host_page_size;
@@ -517,7 +561,7 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
         if (end < real_end) {
             ret = mmap_frag(real_end - qemu_host_page_size,
                             real_end - qemu_host_page_size, end,
-                            prot, flags, fd,
+                            host_prot, flags, fd,
                             offset + real_end - qemu_host_page_size - start);
             if (ret == -1)
                 goto fail;
@@ -533,13 +577,13 @@ abi_long target_mmap(abi_ulong start, abi_ulong len, int prot,
             else
                 offset1 = offset + real_start - start;
             p = mmap(g2h(real_start), real_end - real_start,
-                     prot, flags, fd, offset1);
+                     host_prot, flags, fd, offset1);
             if (p == MAP_FAILED)
                 goto fail;
         }
     }
  the_end1:
-    page_set_flags(start, start + len, prot | PAGE_VALID);
+    page_set_flags(start, start + len, page_flags);
  the_end:
     trace_target_mmap_complete(start);
     if (qemu_loglevel_mask(CPU_LOG_PAGE)) {
diff --git a/linux-user/strace.c b/linux-user/strace.c
index 13981341b3..5e38048643 100644
--- a/linux-user/strace.c
+++ b/linux-user/strace.c
@@ -541,6 +541,7 @@ static void
 print_fdset(int n, abi_ulong target_fds_addr)
 {
     int i;
+    int first = 1;
 
     qemu_log("[");
     if( target_fds_addr ) {
@@ -555,9 +556,12 @@ print_fdset(int n, abi_ulong target_fds_addr)
             return;
 
         for (i=n; i>=0; i--) {
-            if ((tswapal(target_fds[i / TARGET_ABI_BITS]) >> (i & (TARGET_ABI_BITS - 1))) & 1)
-                qemu_log("%d,", i);
+            if ((tswapal(target_fds[i / TARGET_ABI_BITS]) >>
+                (i & (TARGET_ABI_BITS - 1))) & 1) {
+                qemu_log("%s%d", get_comma(first), i);
+                first = 0;
             }
+        }
         unlock_user(target_fds, target_fds_addr, 0);
     }
     qemu_log("]");
diff --git a/linux-user/syscall.c b/linux-user/syscall.c
index 945fc25279..b4a7b605f3 100644
--- a/linux-user/syscall.c
+++ b/linux-user/syscall.c
@@ -1229,7 +1229,9 @@ static inline abi_long copy_to_user_timeval64(abi_ulong target_tv_addr,
     defined(TARGET_NR_nanosleep) || defined(TARGET_NR_clock_settime) || \
     defined(TARGET_NR_utimensat) || defined(TARGET_NR_mq_timedsend) || \
     defined(TARGET_NR_mq_timedreceive) || defined(TARGET_NR_ipc) || \
-    defined(TARGET_NR_semop) || defined(TARGET_NR_semtimedop)
+    defined(TARGET_NR_semop) || defined(TARGET_NR_semtimedop) || \
+    defined(TARGET_NR_timer_settime) || \
+    (defined(TARGET_NR_timerfd_settime) && defined(CONFIG_TIMERFD))
 static inline abi_long target_to_host_timespec(struct timespec *host_ts,
                                                abi_ulong target_addr)
 {
@@ -1245,7 +1247,9 @@ static inline abi_long target_to_host_timespec(struct timespec *host_ts,
 }
 #endif
 
-#if defined(TARGET_NR_clock_settime64) || defined(TARGET_NR_futex_time64)
+#if defined(TARGET_NR_clock_settime64) || defined(TARGET_NR_futex_time64) || \
+    defined(TARGET_NR_timer_settime64) || \
+    (defined(TARGET_NR_timerfd_settime64) && defined(CONFIG_TIMERFD))
 static inline abi_long target_to_host_timespec64(struct timespec *host_ts,
                                                  abi_ulong target_addr)
 {
@@ -6783,46 +6787,74 @@ static inline abi_long target_ftruncate64(void *cpu_env, abi_long arg1,
 
 #if defined(TARGET_NR_timer_settime) || \
     (defined(TARGET_NR_timerfd_settime) && defined(CONFIG_TIMERFD))
-static inline abi_long target_to_host_itimerspec(struct itimerspec *host_itspec,
+static inline abi_long target_to_host_itimerspec(struct itimerspec *host_its,
                                                  abi_ulong target_addr)
 {
-    struct target_itimerspec *target_itspec;
-
-    if (!lock_user_struct(VERIFY_READ, target_itspec, target_addr, 1)) {
+    if (target_to_host_timespec(&host_its->it_interval, target_addr +
+                                offsetof(struct target_itimerspec,
+                                         it_interval)) ||
+        target_to_host_timespec(&host_its->it_value, target_addr +
+                                offsetof(struct target_itimerspec,
+                                         it_value))) {
         return -TARGET_EFAULT;
     }
 
-    host_itspec->it_interval.tv_sec =
-                            tswapal(target_itspec->it_interval.tv_sec);
-    host_itspec->it_interval.tv_nsec =
-                            tswapal(target_itspec->it_interval.tv_nsec);
-    host_itspec->it_value.tv_sec = tswapal(target_itspec->it_value.tv_sec);
-    host_itspec->it_value.tv_nsec = tswapal(target_itspec->it_value.tv_nsec);
+    return 0;
+}
+#endif
+
+#if defined(TARGET_NR_timer_settime64) || \
+    (defined(TARGET_NR_timerfd_settime64) && defined(CONFIG_TIMERFD))
+static inline abi_long target_to_host_itimerspec64(struct itimerspec *host_its,
+                                                   abi_ulong target_addr)
+{
+    if (target_to_host_timespec64(&host_its->it_interval, target_addr +
+                                  offsetof(struct target__kernel_itimerspec,
+                                           it_interval)) ||
+        target_to_host_timespec64(&host_its->it_value, target_addr +
+                                  offsetof(struct target__kernel_itimerspec,
+                                           it_value))) {
+        return -TARGET_EFAULT;
+    }
 
-    unlock_user_struct(target_itspec, target_addr, 1);
     return 0;
 }
 #endif
 
 #if ((defined(TARGET_NR_timerfd_gettime) || \
       defined(TARGET_NR_timerfd_settime)) && defined(CONFIG_TIMERFD)) || \
-    defined(TARGET_NR_timer_gettime) || defined(TARGET_NR_timer_settime)
+      defined(TARGET_NR_timer_gettime) || defined(TARGET_NR_timer_settime)
 static inline abi_long host_to_target_itimerspec(abi_ulong target_addr,
-                                               struct itimerspec *host_its)
-{
-    struct target_itimerspec *target_itspec;
-
-    if (!lock_user_struct(VERIFY_WRITE, target_itspec, target_addr, 0)) {
+                                                 struct itimerspec *host_its)
+{
+    if (host_to_target_timespec(target_addr + offsetof(struct target_itimerspec,
+                                                       it_interval),
+                                &host_its->it_interval) ||
+        host_to_target_timespec(target_addr + offsetof(struct target_itimerspec,
+                                                       it_value),
+                                &host_its->it_value)) {
         return -TARGET_EFAULT;
     }
+    return 0;
+}
+#endif
 
-    target_itspec->it_interval.tv_sec = tswapal(host_its->it_interval.tv_sec);
-    target_itspec->it_interval.tv_nsec = tswapal(host_its->it_interval.tv_nsec);
-
-    target_itspec->it_value.tv_sec = tswapal(host_its->it_value.tv_sec);
-    target_itspec->it_value.tv_nsec = tswapal(host_its->it_value.tv_nsec);
-
-    unlock_user_struct(target_itspec, target_addr, 0);
+#if ((defined(TARGET_NR_timerfd_gettime64) || \
+      defined(TARGET_NR_timerfd_settime64)) && defined(CONFIG_TIMERFD)) || \
+      defined(TARGET_NR_timer_gettime64) || defined(TARGET_NR_timer_settime64)
+static inline abi_long host_to_target_itimerspec64(abi_ulong target_addr,
+                                                   struct itimerspec *host_its)
+{
+    if (host_to_target_timespec64(target_addr +
+                                  offsetof(struct target__kernel_itimerspec,
+                                           it_interval),
+                                  &host_its->it_interval) ||
+        host_to_target_timespec64(target_addr +
+                                  offsetof(struct target__kernel_itimerspec,
+                                           it_value),
+                                  &host_its->it_value)) {
+        return -TARGET_EFAULT;
+    }
     return 0;
 }
 #endif
@@ -11819,6 +11851,17 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
         return ret;
     }
 #endif
+#ifdef TARGET_NR_clock_getres_time64
+    case TARGET_NR_clock_getres_time64:
+    {
+        struct timespec ts;
+        ret = get_errno(clock_getres(arg1, &ts));
+        if (!is_error(ret)) {
+            host_to_target_timespec64(arg2, &ts);
+        }
+        return ret;
+    }
+#endif
 #ifdef TARGET_NR_clock_nanosleep
     case TARGET_NR_clock_nanosleep:
     {
@@ -11876,8 +11919,13 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
             if (!arg3) {
                 tsp = NULL;
             } else {
-                target_to_host_timespec(ts, arg3);
-                target_to_host_timespec(ts+1, arg3+sizeof(struct target_timespec));
+                if (target_to_host_timespec(ts, arg3)) {
+                    return -TARGET_EFAULT;
+                }
+                if (target_to_host_timespec(ts + 1, arg3 +
+                                            sizeof(struct target_timespec))) {
+                    return -TARGET_EFAULT;
+                }
                 tsp = ts;
             }
             if (!arg2)
@@ -12413,6 +12461,32 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
     }
 #endif
 
+#ifdef TARGET_NR_timer_settime64
+    case TARGET_NR_timer_settime64:
+    {
+        target_timer_t timerid = get_timer_id(arg1);
+
+        if (timerid < 0) {
+            ret = timerid;
+        } else if (arg3 == 0) {
+            ret = -TARGET_EINVAL;
+        } else {
+            timer_t htimer = g_posix_timers[timerid];
+            struct itimerspec hspec_new = {{0},}, hspec_old = {{0},};
+
+            if (target_to_host_itimerspec64(&hspec_new, arg3)) {
+                return -TARGET_EFAULT;
+            }
+            ret = get_errno(
+                          timer_settime(htimer, arg2, &hspec_new, &hspec_old));
+            if (arg4 && host_to_target_itimerspec64(arg4, &hspec_old)) {
+                return -TARGET_EFAULT;
+            }
+        }
+        return ret;
+    }
+#endif
+
 #ifdef TARGET_NR_timer_gettime
     case TARGET_NR_timer_gettime:
     {
@@ -12436,6 +12510,29 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
     }
 #endif
 
+#ifdef TARGET_NR_timer_gettime64
+    case TARGET_NR_timer_gettime64:
+    {
+        /* args: timer_t timerid, struct itimerspec64 *curr_value */
+        target_timer_t timerid = get_timer_id(arg1);
+
+        if (timerid < 0) {
+            ret = timerid;
+        } else if (!arg2) {
+            ret = -TARGET_EFAULT;
+        } else {
+            timer_t htimer = g_posix_timers[timerid];
+            struct itimerspec hspec;
+            ret = get_errno(timer_gettime(htimer, &hspec));
+
+            if (host_to_target_itimerspec64(arg2, &hspec)) {
+                ret = -TARGET_EFAULT;
+            }
+        }
+        return ret;
+    }
+#endif
+
 #ifdef TARGET_NR_timer_getoverrun
     case TARGET_NR_timer_getoverrun:
     {
@@ -12489,6 +12586,20 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
         return ret;
 #endif
 
+#if defined(TARGET_NR_timerfd_gettime64) && defined(CONFIG_TIMERFD)
+    case TARGET_NR_timerfd_gettime64:
+        {
+            struct itimerspec its_curr;
+
+            ret = get_errno(timerfd_gettime(arg1, &its_curr));
+
+            if (arg2 && host_to_target_itimerspec64(arg2, &its_curr)) {
+                return -TARGET_EFAULT;
+            }
+        }
+        return ret;
+#endif
+
 #if defined(TARGET_NR_timerfd_settime) && defined(CONFIG_TIMERFD)
     case TARGET_NR_timerfd_settime:
         {
@@ -12512,6 +12623,29 @@ static abi_long do_syscall1(void *cpu_env, int num, abi_long arg1,
         return ret;
 #endif
 
+#if defined(TARGET_NR_timerfd_settime64) && defined(CONFIG_TIMERFD)
+    case TARGET_NR_timerfd_settime64:
+        {
+            struct itimerspec its_new, its_old, *p_new;
+
+            if (arg3) {
+                if (target_to_host_itimerspec64(&its_new, arg3)) {
+                    return -TARGET_EFAULT;
+                }
+                p_new = &its_new;
+            } else {
+                p_new = NULL;
+            }
+
+            ret = get_errno(timerfd_settime(arg1, arg2, p_new, &its_old));
+
+            if (arg4 && host_to_target_itimerspec64(arg4, &its_old)) {
+                return -TARGET_EFAULT;
+            }
+        }
+        return ret;
+#endif
+
 #if defined(TARGET_NR_ioprio_get) && defined(__NR_ioprio_get)
     case TARGET_NR_ioprio_get:
         return get_errno(ioprio_get(arg1, arg2));
diff --git a/linux-user/syscall_defs.h b/linux-user/syscall_defs.h
index 3c261cff0e..427a25f5bc 100644
--- a/linux-user/syscall_defs.h
+++ b/linux-user/syscall_defs.h
@@ -259,6 +259,11 @@ struct target_itimerspec {
     struct target_timespec it_value;
 };
 
+struct target__kernel_itimerspec {
+    struct target__kernel_timespec it_interval;
+    struct target__kernel_timespec it_value;
+};
+
 struct target_timex {
     abi_uint modes;              /* Mode selector */
     abi_long offset;             /* Time offset */