[COMMITTED] libdwfl: Make sure to left shift a unsigned 64bit value in expr_eval.

Mark Wielaard mark@klomp.org
Sun Apr 28 11:34:00 GMT 2019


In frame_unwind.c expr_eval we left shift 1 up to 56 bits. We have to
make sure we don't left shift a 32bit signed value (that would be
undefined behavior). So shift a 1ULL value instead.

Signed-off-by: Mark Wielaard <mark@klomp.org>
---
 libdwfl/ChangeLog      | 5 +++++
 libdwfl/frame_unwind.c | 2 +-
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/libdwfl/ChangeLog b/libdwfl/ChangeLog
index 3e19d9bd1..7c9a018b8 100644
--- a/libdwfl/ChangeLog
+++ b/libdwfl/ChangeLog
@@ -1,3 +1,8 @@
+2019-04-28  Mark Wielaard  <mark@klomp.org>
+
+	* frame_unwind.c (expr_eval): Make sure we left shift a unsigned
+	64bit value.
+
 2019-04-28  Mark Wielaard  <mark@klomp.org>
 
 	* cu.c (addrarange): Only call realloc when naranges is not zero.
diff --git a/libdwfl/frame_unwind.c b/libdwfl/frame_unwind.c
index 8da691ee5..d7dfa5a94 100644
--- a/libdwfl/frame_unwind.c
+++ b/libdwfl/frame_unwind.c
@@ -336,7 +336,7 @@ expr_eval (Dwfl_Frame *state, Dwarf_Frame *frame, const Dwarf_Op *ops,
 		val1 >>= (addr_bytes - op->number) * 8;
 #else
 	      if (op->number < 8)
-		val1 &= (1 << (op->number * 8)) - 1;
+		val1 &= (1ULL << (op->number * 8)) - 1;
 #endif
 	    }
 	  if (! push (val1))
-- 
2.20.1



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