From 0478174d1e2c2a894a35b1cdffc573dca310b438 Mon Sep 17 00:00:00 2001 From: Andreas Schwab Date: Mon, 20 Jan 2020 17:01:50 +0100 Subject: [PATCH] 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) --- NEWS | 1 + debug/tst-backtrace5.c | 12 ++++++++++++ sysdeps/powerpc/powerpc32/backtrace.c | 2 ++ sysdeps/powerpc/powerpc64/backtrace.c | 2 ++ 4 files changed, 17 insertions(+) diff --git a/NEWS b/NEWS index ace1b86fdb..038541c83b 100644 --- a/NEWS +++ b/NEWS @@ -73,6 +73,7 @@ The following bugs are resolved with this release: [25204] Ignore LD_PREFER_MAP_32BIT_EXEC for SUID programs [25225] ld.so fails to link on x86 if GCC defaults to -fcf-protection [25232] No const correctness for strchr et al. for Clang++ + [25423] Array overflow in backtrace on powerpc Security related changes: diff --git a/debug/tst-backtrace5.c b/debug/tst-backtrace5.c index 0e6fb1a024..a117f1544f 100644 --- 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 5422fdd50d..c7b64f9e9b 100644 --- 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 c0c4b48262..0acf17b37e 100644 --- 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]; }