Merge pull request #9318 from douzzer/20251017-linuxkm-signal-handling-tweaks

20251017-linuxkm-signal-handling-tweaks

Author: philljj

.github/workflows/linuxkm.yml

@@ -36,7 +36,7 @@ jobs:
           echo "preparing target kernel $(uname -r)"
           pushd "/lib/modules/$(uname -r)/build" || $(exit 4)
           if [ -f /proc/config.gz ]; then gzip -dc /proc/config.gz > /tmp/.config && sudo mv /tmp/.config . || $(exit 5); elif [ -f "/boot/config-$(uname -r)" ]; then sudo cp -p "/boot/config-$(uname -r)" .config || $(exit 6); fi
-          sudo make -j 4 oldconfig || $(exit 7)
+          sudo make -j 4 olddefconfig || $(exit 7)
           sudo make M="$(pwd)" modules_prepare || $(exit 8)
           popd >/dev/null
 

.wolfssl_known_macro_extras

@@ -105,6 +105,7 @@ CONFIG_ESP_WOLFSSL_NO_HW_RSA_PRI_MULMOD
 CONFIG_ESP_WOLFSSL_NO_STACK_SIZE_BUILD_WARNING
 CONFIG_FREERTOS_HZ
 CONFIG_FREERTOS_UNICORE
+CONFIG_HAVE_KPROBES
 CONFIG_IDF_TARGET
 CONFIG_IDF_TARGET_ARCH_RISCV
 CONFIG_IDF_TARGET_ARCH_XTENSA

configure.ac

@@ -653,10 +653,7 @@ then
     AS_CASE([$xxx_ar_flags],[*'use zero for timestamps and uids/gids'*],[AR_FLAGS="Dcr" lt_ar_flags="Dcr"])
     AS_CASE([$xxx_ranlib_flags],[*'Use zero for symbol map timestamp'*],[RANLIB="${RANLIB} -D"])
 
-    if test "$ENABLED_DEBUG_TRACE_ERRCODES" != "backtrace"
-    then
-        AM_CFLAGS="$AM_CFLAGS -DHAVE_REPRODUCIBLE_BUILD -g0"
-    fi
+    AM_CFLAGS="$AM_CFLAGS -DHAVE_REPRODUCIBLE_BUILD"
 
     # opportunistically use -ffile-prefix-map (added in GCC8 and LLVM10)
 
@@ -739,7 +736,10 @@ AC_ARG_WITH([linux-arch],
 
 if test "x$ENABLED_LINUXKM" = "xyes"
 then
-    AM_CFLAGS="$AM_CFLAGS -DWOLFSSL_LINUXKM -DWC_SIPHASH_NO_ASM"
+    # Currently DWARF 5 is the default debug format, but it results in
+    # "Unsupported DW_TAG_atomic_type(0x47): type: 0x1eefc" in some
+    # kernel module builds.
+    AM_CFLAGS="$AM_CFLAGS -DWOLFSSL_LINUXKM -DWC_SIPHASH_NO_ASM -gdwarf-4"
     ENABLED_NO_LIBRARY=yes
     ENABLED_BENCHMARK=no
     output_objdir="$(realpath "$output_objdir")/linuxkm"

linuxkm/linuxkm_wc_port.h

@@ -129,12 +129,27 @@
     #ifndef WC_LINUXKM_INTR_SIGNALS
         #define WC_LINUXKM_INTR_SIGNALS { SIGKILL, SIGABRT, SIGHUP, SIGINT }
     #endif
+    extern int wc_linuxkm_sig_ignore_begin(void);
+    extern int wc_linuxkm_sig_ignore_end(void);
     extern int wc_linuxkm_check_for_intr_signals(void);
     #ifndef WC_LINUXKM_MAX_NS_WITHOUT_YIELD
         #define WC_LINUXKM_MAX_NS_WITHOUT_YIELD 1000000000
     #endif
     extern void wc_linuxkm_relax_long_loop(void);
 
+    #ifndef WC_SIG_IGNORE_BEGIN
+        #define WC_SIG_IGNORE_BEGIN() wc_linuxkm_sig_ignore_begin()
+    #endif
+    #ifndef WC_SIG_IGNORE_END
+        #define WC_SIG_IGNORE_END() wc_linuxkm_sig_ignore_end()
+    #endif
+    #ifndef WC_CHECK_FOR_INTR_SIGNALS
+        #define WC_CHECK_FOR_INTR_SIGNALS() wc_linuxkm_check_for_intr_signals()
+    #endif
+    #ifndef WC_RELAX_LONG_LOOP
+        #define WC_RELAX_LONG_LOOP() wc_linuxkm_relax_long_loop()
+    #endif
+
     enum wc_svr_flags {
         WC_SVR_FLAG_NONE = 0,
         WC_SVR_FLAG_INHIBIT = 1,
@@ -211,7 +226,7 @@
     _Pragma("GCC diagnostic push");
 
     /* we include all the needed kernel headers with these masked out. else
-     * there are profuse warnings.
+     * there are profuse warnings, especially on older kernels.
      */
     _Pragma("GCC diagnostic ignored \"-Wunused-parameter\"");
     _Pragma("GCC diagnostic ignored \"-Wpointer-arith\"");
@@ -225,6 +240,7 @@
     _Pragma("GCC diagnostic ignored \"-Wtype-limits\"");
     _Pragma("GCC diagnostic ignored \"-Wswitch-enum\"");
     _Pragma("GCC diagnostic ignored \"-Wcast-function-type\""); /* needed for kernel 4.14.336 */
+    _Pragma("GCC diagnostic ignored \"-Wformat-nonliteral\""); /* needed for kernel 4.9.282 */
 
     #include <linux/kconfig.h>
 
@@ -432,10 +448,8 @@
     #endif
     #include <linux/random.h>
 
-    #ifndef __PIE__
-        #if defined(WOLFSSL_LINUXKM_USE_GET_RANDOM_KPROBES) || defined(FIPS_OPTEST)
-            #include <linux/kprobes.h>
-        #endif
+    #if !defined(__PIE__) && defined(CONFIG_HAVE_KPROBES)
+        #include <linux/kprobes.h>
     #endif
 
     #ifdef LINUXKM_LKCAPI_REGISTER
@@ -489,13 +503,6 @@
         #endif /* !__PIE__ */
     #endif /* LINUXKM_LKCAPI_REGISTER */
 
-    #ifndef WC_CHECK_FOR_INTR_SIGNALS
-        #define WC_CHECK_FOR_INTR_SIGNALS() wc_linuxkm_check_for_intr_signals()
-    #endif
-    #ifndef WC_RELAX_LONG_LOOP
-        #define WC_RELAX_LONG_LOOP() wc_linuxkm_relax_long_loop()
-    #endif
-
     /* benchmarks.c uses floating point math, so needs a working
      * SAVE_VECTOR_REGISTERS().
      */
@@ -980,6 +987,8 @@
         typeof(wc_lkm_LockMutex) *wc_lkm_LockMutex;
         #endif
 
+        typeof(wc_linuxkm_sig_ignore_begin) *wc_linuxkm_sig_ignore_begin;
+        typeof(wc_linuxkm_sig_ignore_end) *wc_linuxkm_sig_ignore_end;
         typeof(wc_linuxkm_check_for_intr_signals) *wc_linuxkm_check_for_intr_signals;
         typeof(wc_linuxkm_relax_long_loop) *wc_linuxkm_relax_long_loop;
 
@@ -1220,6 +1229,8 @@
      */
     #define spin_unlock_irqrestore(lock, flags) raw_spin_unlock_irqrestore(&((lock)->rlock), flags)
 
+    #define wc_linuxkm_sig_ignore_begin WC_LKM_INDIRECT_SYM(wc_linuxkm_sig_ignore_begin);
+    #define wc_linuxkm_sig_ignore_end WC_LKM_INDIRECT_SYM(wc_linuxkm_sig_ignore_end);
     #define wc_linuxkm_check_for_intr_signals WC_LKM_INDIRECT_SYM(wc_linuxkm_check_for_intr_signals)
     #define wc_linuxkm_relax_long_loop WC_LKM_INDIRECT_SYM(wc_linuxkm_relax_long_loop)
 

linuxkm/lkcapi_glue.c

@@ -311,16 +311,29 @@ static int linuxkm_lkcapi_sysfs_deinstall(void) {
     return 0;
 }
 
-static volatile int linuxkm_lkcapi_registering_now = 0;
+static wolfSSL_Atomic_Int linuxkm_lkcapi_registering_now = WOLFSSL_ATOMIC_INITIALIZER(0);
 static int linuxkm_lkcapi_registered = 0;
 static int linuxkm_lkcapi_n_registered = 0;
 
 static int linuxkm_lkcapi_register(void)
 {
     int ret = -1;
     int seen_err = 0;
+    int current_linuxkm_lkcapi_registering_now = 0;
+
+    if (! wolfSSL_Atomic_Int_CompareExchange(
+            &linuxkm_lkcapi_registering_now,
+            &current_linuxkm_lkcapi_registering_now,
+            1))
+    {
+        return -EDEADLK;
+    }
 
-    linuxkm_lkcapi_registering_now = 1;
+    if (WC_SIG_IGNORE_BEGIN() < 0) {
+        ret = -ECANCELED;
+        pr_err("ERROR: WC_SIG_IGNORE_BEGIN() failed.\n");
+        goto out_without_sig_ignored;
+    }
 
     ret = linuxkm_lkcapi_sysfs_install();
     if (ret)
@@ -729,7 +742,11 @@ static int linuxkm_lkcapi_register(void)
 
 out:
 
-    linuxkm_lkcapi_registering_now = 0;
+    (void)WC_SIG_IGNORE_END();
+
+out_without_sig_ignored:
+
+    WOLFSSL_ATOMIC_STORE(linuxkm_lkcapi_registering_now, 0);
 
     return ret;
 }
@@ -738,9 +755,27 @@ static int linuxkm_lkcapi_unregister(void)
 {
     int seen_err = 0;
     int n_deregistered = 0;
+    int ret;
+    int current_linuxkm_lkcapi_registering_now = 0;
+
+    if (! wolfSSL_Atomic_Int_CompareExchange(
+            &linuxkm_lkcapi_registering_now,
+            &current_linuxkm_lkcapi_registering_now,
+            1))
+    {
+        return -EDEADLK;
+    }
+
+    if (WC_SIG_IGNORE_BEGIN() < 0) {
+        ret = -ECANCELED;
+        pr_err("ERROR: WC_SIG_IGNORE_BEGIN() failed.\n");
+        goto out_without_sig_ignored;
+    }
 
-    if (linuxkm_lkcapi_n_registered == 0)
-        return -ENOENT;
+    if (linuxkm_lkcapi_n_registered == 0) {
+        ret = -ENOENT;
+        goto out;
+    }
 
 #define UNREGISTER_ALG(alg, alg_class)                                   \
     do {                                                                 \
@@ -863,7 +898,7 @@ static int linuxkm_lkcapi_unregister(void)
      * the system-wide default rng.
      */
     if (wc_linuxkm_drbg_loaded) {
-        int ret = wc_linuxkm_drbg_cleanup();
+        ret = wc_linuxkm_drbg_cleanup();
         if (ret == 0)
             ++n_deregistered;
         else
@@ -975,12 +1010,24 @@ static int linuxkm_lkcapi_unregister(void)
             n_deregistered, n_deregistered == 1 ? "" : "s",
             linuxkm_lkcapi_n_registered, linuxkm_lkcapi_n_registered == 1 ? "s" : "");
 
-    if (linuxkm_lkcapi_n_registered > 0)
-        return -EBUSY;
+    if (linuxkm_lkcapi_n_registered > 0) {
+        ret = -EBUSY;
+        goto out;
+    }
 
     linuxkm_lkcapi_registered = 0;
 
-    return seen_err;
+    ret = seen_err;
+
+out:
+
+    (void)WC_SIG_IGNORE_END();
+
+out_without_sig_ignored:
+
+    WOLFSSL_ATOMIC_STORE(linuxkm_lkcapi_registering_now, 0);
+
+    return ret;
 }
 
 #endif /* !WC_SKIP_INCLUDED_C_FILES */