Extend local PLT reference check

On x86, linker in binutils 2.26 and newer consolidates R_*_JUMP_SLOT with
R_*_GLOB_DAT relocation against the same symbol.  This patch extends
local PLT reference check to support alternate relocations.

	[BZ #18078]
	* scripts/check-localplt.awk: Support alternate relocations.
	* scripts/localplt.awk: Also check relocations in DT_RELA/DT_REL
	sections.
	* sysdeps/unix/sysv/linux/i386/localplt.data: Mark free and
	malloc entries with + REL R_386_GLOB_DAT.
	* sysdeps/x86_64/localplt.data: New file.

1 files changed, 47 insertions, 0 deletions

diff --git a/scripts/localplt.awk b/scripts/localplt.awk
index 84c94d1..f75b3b4 100644
--- a/scripts/localplt.awk
+++ b/scripts/localplt.awk
@@ -13,6 +13,8 @@ FILENAME != lastfile {
   }
   lastfile = FILENAME;
   jmprel_offset = 0;
+  rela_offset = 0;
+  rel_offset = 0;
   delete section_offset_by_address;
 }
 
@@ -43,6 +45,30 @@ in_relocs && relocs_offset == jmprel_offset && NF >= 5 {
   }
 }
 
+in_relocs && relocs_offset == rela_offset && NF >= 5 {
+  # Relocations against GNU_IFUNC symbols are not shown as an hexadecimal
+  # value, but rather as the resolver symbol followed by ().
+  if ($4 ~ /\(\)/) {
+    print whatfile, gensub(/@.*/, "", "g", $5), "RELA", $3
+  } else {
+    symval = strtonum("0x" $4);
+    if (symval != 0)
+      print whatfile, gensub(/@.*/, "", "g", $5), "RELA", $3
+  }
+}
+
+in_relocs && relocs_offset == rel_offset && NF >= 5 {
+  # Relocations against GNU_IFUNC symbols are not shown as an hexadecimal
+  # value, but rather as the resolver symbol followed by ().
+  if ($4 ~ /\(\)/) {
+    print whatfile, gensub(/@.*/, "", "g", $5), "REL", $3
+  } else {
+    symval = strtonum("0x" $4);
+    if (symval != 0)
+      print whatfile, gensub(/@.*/, "", "g", $5), "REL", $3
+  }
+}
+
 in_relocs { next }
 
 $1 == "Relocation" && $2 == "section" && $5 == "offset" {
@@ -62,4 +88,25 @@ $2 == "(JMPREL)" {
   next
 }
 
+$2 == "(RELA)" {
+  rela_addr = strtonum($3);
+  if (rela_addr in section_offset_by_address) {
+    rela_offset = section_offset_by_address[rela_addr];
+  } else {
+    print FILENAME ": *** DT_RELA does not match any section's address";
+    result = 2;
+  }
+  next
+}
+
+$2 == "(REL)" {
+  rel_addr = strtonum($3);
+  if (rel_addr in section_offset_by_address) {
+    rel_offset = section_offset_by_address[rel_addr];
+  } else {
+    print FILENAME ": *** DT_REL does not match any section's address";
+    result = 2;
+  }
+  next
+}
 END { exit(result) }