Fix array overflow in backtrace on PowerPC (bug 25423)

When unwinding through a signal frame the backtrace function on PowerPC
didn't check array bounds when storing the frame address.  Fixes commit
d400dcac5e ("PowerPC: fix backtrace to handle signal trampolines").

(cherry picked from commit d93769405996dfc11d216ddbe415946617b5a494)

diff --git a/NEWS b/NEWS
index 3ccaae396865fc20a8734727575ce4b44fc87e9a..cb62587dbb6caaf3213482ddbc0d28b8b069cb1e 100644 (file)
--- a/NEWS
+++ b/NEWS
@@ -190,6 +190,7 @@ The following bugs are resolved with this release:
   [24155] x32 memcmp can treat positive length as 0 (if sign bit in RDX is set) (CVE-2019-7309)
   [25203] libio: Disable vtable validation for pre-2.1 interposed handles
   [25204] Ignore LD_PREFER_MAP_32BIT_EXEC for SUID programs
+  [25423] Array overflow in backtrace on powerpc
 
 \f
 Version 2.26

diff --git a/debug/tst-backtrace5.c b/debug/tst-backtrace5.c
index 0b85e4482ea853f31efa09a6a7b1bebd5d66b201..57b7dee0f6fcf8db47676142217f7b573b0224f6 100644 (file)
--- a/debug/tst-backtrace5.c
+++ b/debug/tst-backtrace5.c
@@ -88,6 +88,18 @@ handle_signal (int signum)
       }
   /* Symbol names are not available for static functions, so we do not
      check do_test.  */
+
+  /* Check that backtrace does not return more than what fits in the array
+     (bug 25423).  */
+  for (int j = 0; j < NUM_FUNCTIONS; j++)
+    {
+      n = backtrace (addresses, j);
+      if (n > j)
+       {
+         FAIL ();
+         return;
+       }
+    }
 }
 
 NO_INLINE int

diff --git a/sysdeps/powerpc/powerpc32/backtrace.c b/sysdeps/powerpc/powerpc32/backtrace.c
index 187c3b3349535501977df3907f9f5ddd3a9187d4..f0a67008d9da023ecbd6f67cc14120c9045e9c17 100644 (file)
--- a/sysdeps/powerpc/powerpc32/backtrace.c
+++ b/sysdeps/powerpc/powerpc32/backtrace.c
@@ -114,6 +114,8 @@ __backtrace (void **array, int size)
         }
       if (gregset)
        {
+         if (count + 1 == size)
+           break;
          array[++count] = (void*)((*gregset)[PT_NIP]);
          current = (void*)((*gregset)[PT_R1]);
        }

diff --git a/sysdeps/powerpc/powerpc64/backtrace.c b/sysdeps/powerpc/powerpc64/backtrace.c
index 919bf1cfd70b343a94ee092fd2cfbf237653f6c7..dd25b90bfc0f72dbe6d98b80bc86dffd7d4276dc 100644 (file)
--- a/sysdeps/powerpc/powerpc64/backtrace.c
+++ b/sysdeps/powerpc/powerpc64/backtrace.c
@@ -87,6 +87,8 @@ __backtrace (void **array, int size)
       if (is_sigtramp_address (current->return_address))
         {
          struct signal_frame_64 *sigframe = (struct signal_frame_64*) current;
+         if (count + 1 == size)
+           break;
           array[++count] = (void*) sigframe->uc.uc_mcontext.gp_regs[PT_NIP];
          current = (void*) sigframe->uc.uc_mcontext.gp_regs[PT_R1];
        }