[OE-core] [PATCH][dizzy 1/6] glibc/wscanf: CVE-2015-1472
akuster808
akuster808 at gmail.com
Thu Dec 17 16:35:25 UTC 2015
all in series merged to staging.
git at git.yoctoproject.org/poky-contrib.git akuster/dizzy-next
thanks,
Armin
On 12/14/2015 04:24 AM, Sona Sarmadi wrote:
> Fixes a heap buffer overflow in glibc wscanf.
>
> References:
> https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-1472
> https://sourceware.org/ml/libc-alpha/2015-02/msg00119.html
> http://openwall.com/lists/oss-security/2015/02/04/1
>
> Reference to upstream fix:
> https://sourceware.org/git/gitweb.cgi?p=glibc.git;a=commit;
> h=5bd80bfe9ca0d955bfbbc002781bc7b01b6bcb06
>
> Signed-off-by: Sona Sarmadi <sona.sarmadi at enea.com>
> Signed-off-by: Tudor Florea <tudor.florea at enea.com>
> ---
> ...5-1472-wscanf-allocates-too-little-memory.patch | 108 +++++++++++++++++++++
> meta/recipes-core/glibc/glibc_2.20.bb | 1 +
> 2 files changed, 109 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..ab513aa
> --- /dev/null
> +++ b/meta/recipes-core/glibc/glibc/CVE-2015-1472-wscanf-allocates-too-little-memory.patch
> @@ -0,0 +1,108 @@
> +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
> +
> +The patch is from (Paul Pluzhnikov <ppluzhnikov at google.com>):
> +[https://sourceware.org/git/?p=glibc.git;a=patch;h=5bd80bfe9ca0d955bfbbc002781bc7b01b6bcb06]
> +
> +diff -ruN a/ChangeLog b/ChangeLog
> +--- a/ChangeLog 2015-09-22 10:20:14.399408389 +0200
> ++++ b/ChangeLog 2015-09-22 10:33:07.374388595 +0200
> +@@ -1,3 +1,12 @@
> ++2015-02-05 Paul Pluzhnikov <ppluzhnikov at google.com>
> ++
> ++ [BZ #16618] CVE-2015-1472
> ++ * stdio-common/tst-sscanf.c (main): Test for buffer overflow.
> ++ * stdio-common/vfscanf.c (_IO_vfscanf_internal): Compute needed
> ++ size in bytes. Store needed elements in wpmax. Use needed size
> ++ in bytes for extend_alloca.
> ++
> ++
> + 2014-12-16 Florian Weimer <fweimer at redhat.com>
> +
> + [BZ #17630]
> +diff -ruN a/stdio-common/tst-sscanf.c b/stdio-common/tst-sscanf.c
> +--- a/stdio-common/tst-sscanf.c 2015-09-22 10:20:09.995596201 +0200
> ++++ b/stdio-common/tst-sscanf.c 2015-09-22 10:21:39.211791399 +0200
> +@@ -233,5 +233,38 @@
> + }
> + }
> +
> ++ /* 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 -ruN a/stdio-common/vfscanf.c b/stdio-common/vfscanf.c
> +--- a/stdio-common/vfscanf.c 2015-09-22 10:20:14.051423230 +0200
> ++++ b/stdio-common/vfscanf.c 2015-09-22 10:21:39.215791228 +0200
> +@@ -279,9 +279,10 @@
> + 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) \
> +@@ -293,14 +294,13 @@
> + } \
> + 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); \
> diff --git a/meta/recipes-core/glibc/glibc_2.20.bb b/meta/recipes-core/glibc/glibc_2.20.bb
> index a0736cd..cfbc1c2 100644
> --- a/meta/recipes-core/glibc/glibc_2.20.bb
> +++ b/meta/recipes-core/glibc/glibc_2.20.bb
> @@ -48,6 +48,7 @@ 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 \
>
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