libdw: Check .debug_line header field minimum_instr_len fits unit data

	* libdw/dwarf_getsrclines.c (read_line_header): Add lineendp
	check before reading minimum_instr_len byte.

Reported-by: Karan Kurani <karankurani3k@gmail.com>
Signed-off-by: Mark Wielaard <mark@klomp.org>

diff --git a/libdw/dwarf_getsrclines.c b/libdw/dwarf_getsrclines.c
index 76db292966fb2ad22a6c3ea7f9d65593f3a5a307..b3fe7cc87cd9e86c174dd83997acca4db756a0db 100644 (file)
--- a/libdw/dwarf_getsrclines.c
+++ b/libdw/dwarf_getsrclines.c
@@ -247,6 +247,8 @@ read_line_header (Dwarf *dbg, unsigned address_size,
   lh->header_start = linep;
 
   /* Next the minimum instruction length.  */
+  if (unlikely ((size_t) (lineendp - linep) < 1))
+    goto invalid_data;
   lh->minimum_instr_len = *linep++;
 
   /* Next the maximum operations per instruction, in version 4 format.  */