x86, x32, x86_64: print SECCOMP_RET_ERRNO filtered syscalls

This is required to process SECCOMP_RET_ERRNO filtered syscalls on
systems where linux kernel does not change the syscall number to -1.

* syscall.c (is_negated_errno): Move before syscall_fixup_on_sysenter.
(syscall_fixup_on_sysenter) [I386 || X32 || X86_64] : Use it to check
AX register.

diff --git a/syscall.c b/syscall.c
index c5681e2793c438f98713194fe8a03b8a929b5f18..0d1c97ec545986945ab5e05480d2efbfa920e052 100644 (file)
--- a/syscall.c
+++ b/syscall.c
@@ -1593,6 +1593,52 @@ get_scno(struct tcb *tcp)
        return 1;
 }
 
+/*
+ * Cannot rely on __kernel_[u]long_t being defined,
+ * it is quite a recent feature of <asm/posix_types.h>.
+ */
+#ifdef __kernel_long_t
+typedef __kernel_long_t kernel_long_t;
+typedef __kernel_ulong_t kernel_ulong_t;
+#else
+# ifdef X32
+typedef long long kernel_long_t;
+typedef unsigned long long kernel_ulong_t;
+# else
+typedef long kernel_long_t;
+typedef unsigned long kernel_ulong_t;
+# endif
+#endif
+
+/*
+ * Check the syscall return value register value for whether it is
+ * a negated errno code indicating an error, or a success return value.
+ */
+static inline bool
+is_negated_errno(kernel_ulong_t val)
+{
+       kernel_ulong_t max = -(kernel_long_t) nerrnos;
+
+#if SUPPORTED_PERSONALITIES > 1 && SIZEOF_LONG > 4
+       if (current_wordsize < sizeof(val)) {
+               val = (uint32_t) val;
+               max = (uint32_t) max;
+       }
+#elif defined X32
+       /*
+        * current_wordsize is 4 even in personality 0 (native X32)
+        * but truncation _must not_ be done in it.
+        * can't check current_wordsize here!
+        */
+       if (current_personality != 0) {
+               val = (uint32_t) val;
+               max = (uint32_t) max;
+       }
+#endif
+
+       return val > max;
+}
+
 /* Called at each syscall entry.
  * Returns:
  * 0: "ignore this ptrace stop", bail out of trace_syscall_entering() silently.
@@ -1611,7 +1657,7 @@ syscall_fixup_on_sysenter(struct tcb *tcp)
         * that sets orig_eax to -1 in some versions of linux kernel.
         */
        if (i386_regs.orig_eax != -1 &&
-           i386_regs.eax != -ENOSYS) {
+           !is_negated_errno(i386_regs.eax)) {
                if (debug_flag)
                        fprintf(stderr,
                                "not a syscall entry (eax = %ld, orig_eax = %ld)\n",
@@ -1626,7 +1672,7 @@ syscall_fixup_on_sysenter(struct tcb *tcp)
         */
        if (x86_io.iov_len == sizeof(i386_regs)) {
                if ((int) i386_regs.orig_eax != -1 &&
-                   (int) i386_regs.eax != -ENOSYS) {
+                   !is_negated_errno(i386_regs.eax)) {
                        if (debug_flag)
                                fprintf(stderr,
                                        "not a syscall entry (eax = %d, orig_eax = %d)\n",
@@ -1636,7 +1682,7 @@ syscall_fixup_on_sysenter(struct tcb *tcp)
                }
        } else {
                if ((long long) x86_64_regs.orig_rax != -1 &&
-                   (long long) x86_64_regs.rax != -ENOSYS) {
+                   !is_negated_errno(x86_64_regs.rax)) {
                        if (debug_flag)
                                fprintf(stderr,
                                        "not a syscall entry (rax = %lld, orig_rax = %lld)\n",
@@ -2215,52 +2261,6 @@ syscall_fixup_on_sysexit(struct tcb *tcp)
 #endif
 }
 
-/*
- * Cannot rely on __kernel_[u]long_t being defined,
- * it is quite a recent feature of <asm/posix_types.h>.
- */
-#ifdef __kernel_long_t
-typedef __kernel_long_t kernel_long_t;
-typedef __kernel_ulong_t kernel_ulong_t;
-#else
-# ifdef X32
-typedef long long kernel_long_t;
-typedef unsigned long long kernel_ulong_t;
-# else
-typedef long kernel_long_t;
-typedef unsigned long kernel_ulong_t;
-# endif
-#endif
-
-/*
- * Check the syscall return value register value for whether it is
- * a negated errno code indicating an error, or a success return value.
- */
-static inline bool
-is_negated_errno(kernel_ulong_t val)
-{
-       kernel_ulong_t max = -(kernel_long_t) nerrnos;
-
-#if SUPPORTED_PERSONALITIES > 1 && SIZEOF_LONG > 4
-       if (current_wordsize < sizeof(val)) {
-               val = (uint32_t) val;
-               max = (uint32_t) max;
-       }
-#elif defined X32
-       /*
-        * current_wordsize is 4 even in personality 0 (native X32)
-        * but truncation _must not_ be done in it.
-        * can't check current_wordsize here!
-        */
-       if (current_personality != 0) {
-               val = (uint32_t) val;
-               max = (uint32_t) max;
-       }
-#endif
-
-       return val > max;
-}
-
 /* Returns:
  * 1: ok, continue in trace_syscall_exiting().
  * -1: error, trace_syscall_exiting() should print error indicator