[OE-core] [PATCH 1/2] glibc: CVE-2015-1472: wscanf allocates too little memory
Haris Okanovic
haris.okanovic at ni.com
Fri May 8 14:28:27 UTC 2015
Backport Paul Pluzhnikov's glibc patch for CVE-2015-1472:
Under certain conditions wscanf can allocate too little memory for the
to-be-scanned arguments and overflow the allocated buffer. The
implementation now correctly computes the required buffer size when
using malloc.
https://sourceware.org/bugzilla/show_bug.cgi?id=16618
Signed-off-by: Haris Okanovic <haris.okanovic at ni.com>
Signed-off-by: Ken Sharp <ken.sharp at ni.com>
Reviewed-by: Rich Tollerton <rich.tollerton at ni.com>
---
Natinst-CAR-ID: 518552
Natinst-ReviewBoard-ID: 96712
---
...5-1472-wscanf-allocates-too-little-memory.patch | 127 +++++++++++++++++++++
meta/recipes-core/glibc/glibc_2.20.bb | 1 +
2 files changed, 128 insertions(+)
create mode 100644 meta/recipes-core/glibc/glibc/CVE-2015-1472-wscanf-allocates-too-little-memory.patch
diff --git a/meta/recipes-core/glibc/glibc/CVE-2015-1472-wscanf-allocates-too-little-memory.patch b/meta/recipes-core/glibc/glibc/CVE-2015-1472-wscanf-allocates-too-little-memory.patch
new file mode 100644
index 0000000..4ffd609
--- /dev/null
+++ b/meta/recipes-core/glibc/glibc/CVE-2015-1472-wscanf-allocates-too-little-memory.patch
@@ -0,0 +1,127 @@
+From 5bd80bfe9ca0d955bfbbc002781bc7b01b6bcb06 Mon Sep 17 00:00:00 2001
+From: Paul Pluzhnikov <ppluzhnikov at google.com>
+Date: Fri, 6 Feb 2015 00:30:42 -0500
+Subject: [PATCH] CVE-2015-1472: wscanf allocates too little memory
+
+BZ #16618
+
+Under certain conditions wscanf can allocate too little memory for the
+to-be-scanned arguments and overflow the allocated buffer. The
+implementation now correctly computes the required buffer size when
+using malloc.
+
+A regression test was added to tst-sscanf.
+
+Upstream-Status: Backport
+https://sourceware.org/bugzilla/show_bug.cgi?id=16618
+---
+ stdio-common/tst-sscanf.c | 33 +++++++++++++++++++++++++++++++++
+ stdio-common/vfscanf.c | 12 ++++++------
+ 2 files changed, 39 insertions(+), 6 deletions(-)
+
+diff --git a/stdio-common/tst-sscanf.c b/stdio-common/tst-sscanf.c
+index aece3f2f290088b2c08441cf85f2b915a61b9789..8a2eb9e39c4752a30941753d7f0325c2aa352fd1 100644
+--- a/stdio-common/tst-sscanf.c
++++ b/stdio-common/tst-sscanf.c
+@@ -226,12 +226,45 @@ main (void)
+ result = 1;
+ }
+ else if (ret == 2 && c != double_tests2[i].residual)
+ {
+ printf ("double_tests2[%d] stopped at '%c' != '%c'\n",
+ i, c, double_tests2[i].residual);
+ result = 1;
+ }
+ }
+
++ /* BZ #16618
++ The test will segfault during SSCANF if the buffer overflow
++ is not fixed. The size of `s` is such that it forces the use
++ of malloc internally and this triggers the incorrect computation.
++ Thus the value for SIZE is arbitrariy high enough that malloc
++ is used. */
++ {
++#define SIZE 131072
++ CHAR *s = malloc ((SIZE + 1) * sizeof (*s));
++ if (s == NULL)
++ abort ();
++ for (size_t i = 0; i < SIZE; i++)
++ s[i] = L('0');
++ s[SIZE] = L('\0');
++ int i = 42;
++ /* Scan multi-digit zero into `i`. */
++ if (SSCANF (s, L("%d"), &i) != 1)
++ {
++ printf ("FAIL: bug16618: SSCANF did not read one input item.\n");
++ result = 1;
++ }
++ if (i != 0)
++ {
++ printf ("FAIL: bug16618: Value of `i` was not zero as expected.\n");
++ result = 1;
++ }
++ free (s);
++ if (result != 1)
++ printf ("PASS: bug16618: Did not crash.\n");
++#undef SIZE
++ }
++
++
+ return result;
+ }
+diff --git a/stdio-common/vfscanf.c b/stdio-common/vfscanf.c
+index cd129a81dee57e5e06ccb0e676e0de3fd52469ca..0e204e7b326d848716222f40b5b82b8256ed1b77 100644
+--- a/stdio-common/vfscanf.c
++++ b/stdio-common/vfscanf.c
+@@ -265,42 +265,42 @@ _IO_vfscanf_internal (_IO_FILE *s, const char *format, _IO_va_list argptr,
+ CHAR_T *wp = NULL; /* Workspace. */
+ size_t wpmax = 0; /* Maximal size of workspace. */
+ size_t wpsize; /* Currently used bytes in workspace. */
+ bool use_malloc = false;
+ #define ADDW(Ch) \
+ do \
+ { \
+ if (__glibc_unlikely (wpsize == wpmax)) \
+ { \
+ CHAR_T *old = wp; \
+- size_t newsize = (UCHAR_MAX + 1 > 2 * wpmax \
+- ? UCHAR_MAX + 1 : 2 * wpmax); \
+- if (use_malloc || !__libc_use_alloca (newsize)) \
++ bool fits = __glibc_likely (wpmax <= SIZE_MAX / sizeof (CHAR_T) / 2); \
++ size_t wpneed = MAX (UCHAR_MAX + 1, 2 * wpmax); \
++ size_t newsize = fits ? wpneed * sizeof (CHAR_T) : SIZE_MAX; \
++ if (!__libc_use_alloca (newsize)) \
+ { \
+ wp = realloc (use_malloc ? wp : NULL, newsize); \
+ if (wp == NULL) \
+ { \
+ if (use_malloc) \
+ free (old); \
+ done = EOF; \
+ goto errout; \
+ } \
+ if (! use_malloc) \
+ MEMCPY (wp, old, wpsize); \
+- wpmax = newsize; \
++ wpmax = wpneed; \
+ use_malloc = true; \
+ } \
+ else \
+ { \
+ size_t s = wpmax * sizeof (CHAR_T); \
+- wp = (CHAR_T *) extend_alloca (wp, s, \
+- newsize * sizeof (CHAR_T)); \
++ wp = (CHAR_T *) extend_alloca (wp, s, newsize); \
+ wpmax = s / sizeof (CHAR_T); \
+ if (old != NULL) \
+ MEMCPY (wp, old, wpsize); \
+ } \
+ } \
+ wp[wpsize++] = (Ch); \
+ } \
+ while (0)
+
+ #ifdef __va_copy
+--
+2.2.2
+
diff --git a/meta/recipes-core/glibc/glibc_2.20.bb b/meta/recipes-core/glibc/glibc_2.20.bb
index 3277f7a..e3427dd 100644
--- a/meta/recipes-core/glibc/glibc_2.20.bb
+++ b/meta/recipes-core/glibc/glibc_2.20.bb
@@ -46,6 +46,7 @@ CVEPATCHES = "\
file://CVE-2014-7817-wordexp-fails-to-honour-WRDE_NOCMD.patch \
file://CVE-2012-3406-Stack-overflow-in-vfprintf-BZ-16617.patch \
file://CVE-2014-9402_endless-loop-in-getaddr_r.patch \
+ file://CVE-2015-1472-wscanf-allocates-too-little-memory.patch \
"
LIC_FILES_CHKSUM = "file://LICENSES;md5=e9a558e243b36d3209f380deb394b213 \
file://COPYING;md5=b234ee4d69f5fce4486a80fdaf4a4263 \
--
2.2.2
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