eglibc: CVE-2012-3406 Stack overflow in vfprintf

printf() unbound alloca() usage in case of positional
parameters + many format specs

Changes in the NEWS and ChangeLog files from the original upstream
commit have been ignored

References
http://www.openwall.com/lists/oss-security/2012/07/11/5
https://sourceware.org/bugzilla/show_bug.cgi?id=16617

Signed-off-by: Sona Sarmadi <sona.sarmadi@enea.com>

2 files changed, 274 insertions, 0 deletions

diff --git a/meta/recipes-core/eglibc/eglibc-2.19/CVE-2012-3406-Stack-overflow-in-vfprintf-BZ-16617.patch b/meta/recipes-core/eglibc/eglibc-2.19/CVE-2012-3406-Stack-overflow-in-vfprintf-BZ-16617.patch
new file mode 100644
index 0000000000..c018bdd6c7
--- /dev/null
+++ b/meta/recipes-core/eglibc/eglibc-2.19/CVE-2012-3406-Stack-overflow-in-vfprintf-BZ-16617.patch
@@ -0,0 +1,273 @@
+From a5357b7ce2a2982c5778435704bcdb55ce3667a0 Mon Sep 17 00:00:00 2001
+From: Jeff Law <law@redhat.com>
+Date: Mon, 15 Dec 2014 10:09:32 +0100
+Subject: [PATCH] CVE-2012-3406: Stack overflow in vfprintf [BZ #16617]
+
+A larger number of format specifiers coudld cause a stack overflow,
+potentially allowing to bypass _FORTIFY_SOURCE format string
+protection.
+---
+ stdio-common/Makefile   |  2 +-
+ stdio-common/bug23-2.c  | 70 +++++++++++++++++++++++++++++++++++++++++++++++++
+ stdio-common/bug23-3.c  | 50 +++++++++++++++++++++++++++++++++++
+ stdio-common/bug23-4.c  | 31 ++++++++++++++++++++++
+ stdio-common/vfprintf.c | 40 ++++++++++++++++++++++++++--
+ create mode 100644 stdio-common/bug23-2.c
+ create mode 100644 stdio-common/bug23-3.c
+ create mode 100644 stdio-common/bug23-4.c
+
+Index: git/stdio-common/bug23-2.c
+===================================================================
+--- /dev/null
++++ git/stdio-common/bug23-2.c
+@@ -0,0 +1,70 @@
++#include <stdio.h>
++#include <string.h>
++#include <stdlib.h>
++
++static const char expected[] = "\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55\
++\n\
++a\n\
++abbcd55%%%%%%%%%%%%%%%%%%%%%%%%%%\n";
++
++static int
++do_test (void)
++{
++  char *buf = malloc (strlen (expected) + 1);
++  snprintf (buf, strlen (expected) + 1,
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++           "%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%\n",
++           "a", "b", "c", "d", 5);
++  return strcmp (buf, expected) != 0;
++}
++
++#define TEST_FUNCTION do_test ()
++#include "../test-skeleton.c"
+Index: git/stdio-common/bug23-3.c
+===================================================================
+--- /dev/null
++++ git/stdio-common/bug23-3.c
+@@ -0,0 +1,50 @@
++#include <stdio.h>
++#include <string.h>
++#include <stdlib.h>
++
++int
++do_test (void)
++{
++  size_t instances = 16384;
++#define X0 "\n%1$s\n" "%1$s" "%2$s" "%2$s" "%3$s" "%4$s" "%5$d" "%5$d"
++  const char *item = "\na\nabbcd55";
++#define X3 X0 X0 X0 X0 X0 X0 X0 X0
++#define X6 X3 X3 X3 X3 X3 X3 X3 X3
++#define X9 X6 X6 X6 X6 X6 X6 X6 X6
++#define X12 X9 X9 X9 X9 X9 X9 X9 X9
++#define X14 X12 X12 X12 X12
++#define TRAILER "%%%%%%%%%%%%%%%%%%%%%%%%%%"
++#define TRAILER2 TRAILER TRAILER
++  size_t length = instances * strlen (item) + strlen (TRAILER) + 1;
++
++  char *buf = malloc (length + 1);
++  snprintf (buf, length + 1,
++           X14 TRAILER2 "\n",
++           "a", "b", "c", "d", 5);
++
++  const char *p = buf;
++  size_t i;
++  for (i = 0; i < instances; ++i)
++    {
++      const char *expected;
++      for (expected = item; *expected; ++expected)
++       {
++         if (*p != *expected)
++           {
++             printf ("mismatch at offset %zu (%zu): expected %d, got %d\n",
++                     (size_t) (p - buf), i, *expected & 0xFF, *p & 0xFF);
++             return 1;
++           }
++         ++p;
++       }
++    }
++  if (strcmp (p, TRAILER "\n") != 0)
++    {
++      printf ("mismatch at trailer: [%s]\n", p);
++      return 1;
++    }
++  free (buf);
++  return 0;
++}
++#define TEST_FUNCTION do_test ()
++#include "../test-skeleton.c"
+Index: git/stdio-common/bug23-4.c
+===================================================================
+--- /dev/null
++++ git/stdio-common/bug23-4.c
+@@ -0,0 +1,31 @@
++#include <stdio.h>
++#include <stdlib.h>
++#include <string.h>
++#include <sys/resource.h>
++
++#define LIMIT 1000000
++
++int
++main (void)
++{
++  struct rlimit lim;
++  getrlimit (RLIMIT_STACK, &lim);
++  lim.rlim_cur = 1048576;
++  setrlimit (RLIMIT_STACK, &lim);
++  char *fmtstr = malloc (4 * LIMIT + 1);
++  if (fmtstr == NULL)
++    abort ();
++  char *output = malloc (LIMIT + 1);
++  if (output == NULL)
++    abort ();
++  for (size_t i = 0; i < LIMIT; i++)
++    memcpy (fmtstr + 4 * i, "%1$d", 4);
++  fmtstr[4 * LIMIT] = '\0';
++  int ret = snprintf (output, LIMIT + 1, fmtstr, 0);
++  if (ret != LIMIT)
++    abort ();
++  for (size_t i = 0; i < LIMIT; i++)
++    if (output[i] != '0')
++      abort ();
++  return 0;
++}
+Index: git/stdio-common/vfprintf.c
+===================================================================
+--- git.orig/stdio-common/vfprintf.c
++++ git/stdio-common/vfprintf.c
+@@ -276,6 +276,12 @@ vfprintf (FILE *s, const CHAR_T *format,
+   /* For the argument descriptions, which may be allocated on the heap.  */
+   void *args_malloced = NULL;
+ 
++  /* For positional argument handling.  */
++  struct printf_spec *specs;
++
++  /* Track if we malloced the SPECS array and thus must free it.  */
++  bool specs_malloced = false;
++
+   /* This table maps a character into a number representing a
+      class.  In each step there is a destination label for each
+      class.  */
+@@ -1699,8 +1705,8 @@ do_positional:
+     size_t nspecs = 0;
+     /* A more or less arbitrary start value.  */
+     size_t nspecs_size = 32 * sizeof (struct printf_spec);
+-    struct printf_spec *specs = alloca (nspecs_size);
+ 
++    specs = alloca (nspecs_size);
+     /* The number of arguments the format string requests.  This will
+        determine the size of the array needed to store the argument
+        attributes.  */
+@@ -1743,11 +1749,39 @@ do_positional:
+        if (nspecs * sizeof (*specs) >= nspecs_size)
+          {
+            /* Extend the array of format specifiers.  */
++           if (nspecs_size * 2 < nspecs_size)
++             {
++               __set_errno (ENOMEM);
++               done = -1;
++               goto all_done;
++             }
+            struct printf_spec *old = specs;
+-           specs = extend_alloca (specs, nspecs_size, 2 * nspecs_size);
++           if (__libc_use_alloca (2 * nspecs_size))
++             specs = extend_alloca (specs, nspecs_size, 2 * nspecs_size);
++           else
++             {
++               nspecs_size *= 2;
++               specs = malloc (nspecs_size);
++               if (specs == NULL)
++                 {
++                   __set_errno (ENOMEM);
++                   specs = old;
++                   done = -1;
++                   goto all_done;
++                 }
++             }
+ 
+            /* Copy the old array's elements to the new space.  */
+            memmove (specs, old, nspecs * sizeof (*specs));
++
++           /* If we had previously malloc'd space for SPECS, then
++              release it after the copy is complete.  */
++           if (specs_malloced)
++             free (old);
++
++           /* Now set SPECS_MALLOCED if needed.  */
++           if (!__libc_use_alloca (nspecs_size))
++             specs_malloced = true;
+          }
+ 
+        /* Parse the format specifier.  */
+@@ -2068,6 +2102,8 @@ do_positional:
+   }
+ 
+ all_done:
++  if (specs_malloced)
++    free (specs);
+   if (__glibc_unlikely (args_malloced != NULL))
+     free (args_malloced);
+   if (__glibc_unlikely (workstart != NULL))
+Index: git/stdio-common/Makefile
+===================================================================
+--- git.orig/stdio-common/Makefile
++++ git/stdio-common/Makefile
+@@ -66,7 +66,7 @@ tests := tstscanf test_rdwr test-popen t
+         tst-fwrite bug16 bug17 tst-sprintf2 bug18 \
+         bug19 tst-popen2 scanf14 scanf15 bug21 bug22 scanf16 scanf17 \
+         tst-setvbuf1 bug23 bug24 bug-vfprintf-nargs tst-sprintf3 bug25 \
+-        tst-printf-round bug26
++        tst-printf-round bug23-2 bug23-3 bug23-4
+ tests-$(OPTION_EGLIBC_LOCALE_CODE) \
+       += tst-sscanf tst-swprintf test-vfprintf bug14 scanf13 tst-grouping
diff --git a/meta/recipes-core/eglibc/eglibc_2.19.bb b/meta/recipes-core/eglibc/eglibc_2.19.bb
index ba79f27d61..1ef1a429d2 100644
--- a/meta/recipes-core/eglibc/eglibc_2.19.bb
+++ b/meta/recipes-core/eglibc/eglibc_2.19.bb
@@ -27,6 +27,7 @@ SRC_URI = "http://downloads.yoctoproject.org/releases/eglibc/eglibc-${PV}-svnr25
            file://ppce6500-32b_slow_ieee754_sqrt.patch \
            file://CVE-2014-5119.patch \
            file://CVE-2014-7817-wordexp-fails-to-honour-WRDE_NOCMD.patch \
+           file://CVE-2012-3406-Stack-overflow-in-vfprintf-BZ-16617.patch \
           "
 SRC_URI[md5sum] = "197836c2ba42fb146e971222647198dd"
 SRC_URI[sha256sum] = "baaa030531fc308f7820c46acdf8e1b2f8e3c1f40bcd28b6e440d1c95d170d4c"