[binutils-gdb] sim/ppc: initialize a memory buffer in all cases

[Andrew Burgess]

https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=548d634f1b61571f118c3133ce0e8986714c8fd6

commit 548d634f1b61571f118c3133ce0e8986714c8fd6
Author: Andrew Burgess <aburgess@redhat.com>
Date:   Wed Oct 19 15:07:40 2022 +0100

    sim/ppc: initialize a memory buffer in all cases
    
    In the ppc simulator's do_fstat function, which provides the fstat
    call for the simulator, if the fstat is going to fail then we
    currently write an uninitialized buffer into the simulated target.
    
    In theory, I think this is fine, we also write the error status into
    the simulated target, so, given that the fstat has failed, the target
    shouldn't be relying on the buffer contents.
    
    However, writing an uninitialized buffer means we might leak simulator
    private data into the simulated target, which is probably a bad thing.
    Plus it probably makes life easier if something consistent, like all
    zeros, is written rather than random junk, which might look like a
    successful call (except for the error code).
    
    So, in this commit, I initialize the stat buffer to zero before
    it is potentially used.  If the stat call is not made then the buffer
    will be left initialized as all zeros.

Diff:
---
 sim/ppc/emul_netbsd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sim/ppc/emul_netbsd.c b/sim/ppc/emul_netbsd.c
index 322b584a3f1..a8bfd27610e 100644
--- a/sim/ppc/emul_netbsd.c
+++ b/sim/ppc/emul_netbsd.c
@@ -879,7 +879,7 @@ do_fstat(os_emul_data *emul,
 {
   int fd = cpu_registers(processor)->gpr[arg0];
   unsigned_word stat_buf_addr = cpu_registers(processor)->gpr[arg0+1];
-  struct stat buf;
+  struct stat buf = {};
   int status;
 #ifdef SYS_fstat
   SYS(fstat);