From: Alan Modra <amodra@gmail.com>
Date: Fri, 20 Dec 2013 13:27:52 +0000 (+1030)
Subject: Don't segv on cie.initial_instructions[] overflow.
X-Git-Tag: gdb-7.7-release~148
X-Git-Url: https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;a=commitdiff_plain;h=99d190fac4d2aab238cfc798dc5c28ab41456882

Don't segv on cie.initial_instructions[] overflow.

Don't attempt to merge CIEs with a larger number of insns than will
fit in the buffer.

	* elf-eh-frame.c (cie_eq): Return false when initial_insn_length
	is too large.
	(cie_compute_hash): Don't exceed bounds of initial_instructions.
	(_bfd_elf_parse_eh_frame): Always set initial_insn_length, and
	save as much of insns to initial_instructions[] as will fit.
---

diff --git a/bfd/elf-eh-frame.c b/bfd/elf-eh-frame.c
index 832a991..4b6e8ea 100644
--- a/bfd/elf-eh-frame.c
+++ b/bfd/elf-eh-frame.c
@@ -235,6 +235,7 @@ cie_eq (const void *e1, const void *e2)
       && c1->lsda_encoding == c2->lsda_encoding
       && c1->fde_encoding == c2->fde_encoding
       && c1->initial_insn_length == c2->initial_insn_length
+      && c1->initial_insn_length <= sizeof (c1->initial_instructions)
       && memcmp (c1->initial_instructions,
 		 c2->initial_instructions,
 		 c1->initial_insn_length) == 0)
@@ -254,6 +255,7 @@ static hashval_t
 cie_compute_hash (struct cie *c)
 {
   hashval_t h = 0;
+  size_t len;
   h = iterative_hash_object (c->length, h);
   h = iterative_hash_object (c->version, h);
   h = iterative_hash (c->augmentation, strlen (c->augmentation) + 1, h);
@@ -267,7 +269,10 @@ cie_compute_hash (struct cie *c)
   h = iterative_hash_object (c->lsda_encoding, h);
   h = iterative_hash_object (c->fde_encoding, h);
   h = iterative_hash_object (c->initial_insn_length, h);
-  h = iterative_hash (c->initial_instructions, c->initial_insn_length, h);
+  len = c->initial_insn_length;
+  if (len > sizeof (c->initial_instructions))
+    len = sizeof (c->initial_instructions);
+  h = iterative_hash (c->initial_instructions, len, h);
   c->hash = h;
   return h;
 }
@@ -762,11 +767,10 @@ _bfd_elf_parse_eh_frame (bfd *abfd, struct bfd_link_info *info,
 	    cie->fde_encoding = DW_EH_PE_absptr;
 
 	  initial_insn_length = end - buf;
-	  if (initial_insn_length <= sizeof (cie->initial_instructions))
-	    {
-	      cie->initial_insn_length = initial_insn_length;
-	      memcpy (cie->initial_instructions, buf, initial_insn_length);
-	    }
+	  cie->initial_insn_length = initial_insn_length;
+	  memcpy (cie->initial_instructions, buf,
+		  initial_insn_length <= sizeof (cie->initial_instructions)
+		  ? initial_insn_length : sizeof (cie->initial_instructions));
 	  insns = buf;
 	  buf += initial_insn_length;
 	  ENSURE_NO_RELOCS (buf);