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* [PATCH] [PR corefiles/17808] i386: Fix internal error when prstatus in core file is too big
@ 2015-01-08 16:16 Andreas Arnez
  2015-01-08 16:43 ` [testsuite patch] for: " Jan Kratochvil
  0 siblings, 1 reply; 25+ messages in thread
From: Andreas Arnez @ 2015-01-08 16:16 UTC (permalink / raw)
  To: gdb-patches; +Cc: jan.kratochvil

As reported in PR 17808, a test case with a forged (invalid) core file
can crash GDB with an assertion failure.  In that particular case the
prstatus of an i386 core file looks like that from an AMD64 core file,
i.e., it is larger than GDB would expect.

The patch replaces the assertion by a warning and skips the invalid
core file register section.  In this way it is guaranteed that no
bogus register values are read from the badly formatted section.

Note that this behavior deviates from the default policy: In general, if
some future kernel adds new registers to a register set, then a GDB
unaware of this extension would read the known subset and just ignore
the unknown bytes.

gdb/ChangeLog:

	PR corefiles/17808
	* i386-tdep.c (i386_supply_gregset): Instead of yielding an
	internal error on unexpected input buffer size, ignore the data
	and emit a warning.

---
 gdb/i386-tdep.c |    7 ++++++-
 1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/gdb/i386-tdep.c b/gdb/i386-tdep.c
index 7d174c4..d02aaf2 100644
--- a/gdb/i386-tdep.c
+++ b/gdb/i386-tdep.c
@@ -3727,7 +3727,12 @@ i386_supply_gregset (const struct regset *regset, struct regcache *regcache,
   const gdb_byte *regs = gregs;
   int i;
 
-  gdb_assert (len == tdep->sizeof_gregset);
+  if (len != tdep->sizeof_gregset)
+    {
+      /* Buffer has unknown size: assume wrong format.  */
+      warning (_("Bad size of general register section"));
+      return;
+    }
 
   for (i = 0; i < tdep->gregset_num_regs; i++)
     {
-- 
1.7.9.5


^ permalink raw reply	[flat|nested] 25+ messages in thread

end of thread, other threads:[~2015-07-16 16:10 UTC | newest]

Thread overview: 25+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2015-01-08 16:16 [PATCH] [PR corefiles/17808] i386: Fix internal error when prstatus in core file is too big Andreas Arnez
2015-01-08 16:43 ` [testsuite patch] for: " Jan Kratochvil
2015-01-09  9:47   ` Andreas Arnez
2015-01-09 16:45     ` Pedro Alves
2015-01-09 16:59       ` Mark Kettenis
2015-01-09 17:19         ` Pedro Alves
2015-01-09 19:35           ` Mark Kettenis
2015-01-09 20:11             ` Pedro Alves
2015-01-09 20:30               ` Mark Kettenis
2015-01-12 14:30                 ` Andreas Arnez
2015-01-09 19:27       ` Andreas Arnez
2015-02-05  7:38   ` ping: " Jan Kratochvil
2015-02-05  9:47     ` Pedro Alves
2015-02-14 15:12       ` Jan Kratochvil
2015-02-17 12:56         ` Pedro Alves
2015-02-17 16:56           ` Jan Kratochvil
2015-02-21 14:28             ` [commit] " Jan Kratochvil
2015-07-14  8:52             ` ping: " Yao Qi
2015-07-14 18:07               ` Jan Kratochvil
2015-07-15 16:14                 ` Yao Qi
2015-07-15 16:58                   ` Jan Kratochvil
2015-07-16 14:15                     ` Yao Qi
2015-07-16 14:37                       ` Jan Kratochvil
2015-07-16 15:35                         ` Yao Qi
2015-07-16 16:10                           ` [commit] " Jan Kratochvil

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