[OE-core] [master][morty][krogoth][PATCH] musl: Security fix CVE-2016-8859

[Khem Raj]

On Wed, Oct 19, 2016 at 6:00 PM, Armin Kuster <akuster808 at gmail.com> wrote:
> From: Armin Kuster <akuster at mvista.com>
>
> CVE-2016-8859: TRE & musl libc regex integer overflows in buffer size computations
>
> Affects musl <= 1.1.15

this is ok. I have a version bump planned for master soon after so
master should be covered.
>
> Signed-off-by: Armin Kuster <akuster at mvista.com>
> ---
>  meta/recipes-core/musl/files/CVE-2016-8859.patch | 79 ++++++++++++++++++++++++
>  meta/recipes-core/musl/musl_git.bb               |  1 +
>  2 files changed, 80 insertions(+)
>  create mode 100644 meta/recipes-core/musl/files/CVE-2016-8859.patch
>
> diff --git a/meta/recipes-core/musl/files/CVE-2016-8859.patch b/meta/recipes-core/musl/files/CVE-2016-8859.patch
> new file mode 100644
> index 0000000..82da86f
> --- /dev/null
> +++ b/meta/recipes-core/musl/files/CVE-2016-8859.patch
> @@ -0,0 +1,79 @@
> +From c3edc06d1e1360f3570db9155d6b318ae0d0f0f7 Mon Sep 17 00:00:00 2001
> +From: Rich Felker <dalias at aerifal.cx>
> +Date: Thu, 6 Oct 2016 18:34:58 -0400
> +Subject: [PATCH] fix missing integer overflow checks in regexec buffer size
> + computations
> +
> +most of the possible overflows were already ruled out in practice by
> +regcomp having already succeeded performing larger allocations.
> +however at least the num_states*num_tags multiplication can clearly
> +overflow in practice. for safety, check them all, and use the proper
> +type, size_t, rather than int.
> +
> +also improve comments, use calloc in place of malloc+memset, and
> +remove bogus casts.
> +
> +Upstream-Status: Backport
> +CVE: CVE-2016-8859
> +
> +Signed-off-by: Armin Kuster <akuster at mvista.com>
> +
> +---
> + src/regex/regexec.c | 23 ++++++++++++++++++-----
> + 1 file changed, 18 insertions(+), 5 deletions(-)
> +
> +diff --git a/src/regex/regexec.c b/src/regex/regexec.c
> +index 16c5d0a..dd52319 100644
> +--- a/src/regex/regexec.c
> ++++ b/src/regex/regexec.c
> +@@ -34,6 +34,7 @@
> + #include <wchar.h>
> + #include <wctype.h>
> + #include <limits.h>
> ++#include <stdint.h>
> +
> + #include <regex.h>
> +
> +@@ -206,11 +207,24 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string,
> +
> +   /* Allocate memory for temporary data required for matching.        This needs to
> +      be done for every matching operation to be thread safe.  This allocates
> +-     everything in a single large block from the stack frame using alloca()
> +-     or with malloc() if alloca is unavailable. */
> ++     everything in a single large block with calloc(). */
> +   {
> +-    int tbytes, rbytes, pbytes, xbytes, total_bytes;
> ++    size_t tbytes, rbytes, pbytes, xbytes, total_bytes;
> +     char *tmp_buf;
> ++
> ++    /* Ensure that tbytes and xbytes*num_states cannot overflow, and that
> ++     * they don't contribute more than 1/8 of SIZE_MAX to total_bytes. */
> ++    if (num_tags > SIZE_MAX/(8 * sizeof(int) * tnfa->num_states))
> ++      goto error_exit;
> ++
> ++    /* Likewise check rbytes. */
> ++    if (tnfa->num_states+1 > SIZE_MAX/(8 * sizeof(*reach_next)))
> ++      goto error_exit;
> ++
> ++    /* Likewise check pbytes. */
> ++    if (tnfa->num_states > SIZE_MAX/(8 * sizeof(*reach_pos)))
> ++      goto error_exit;
> ++
> +     /* Compute the length of the block we need. */
> +     tbytes = sizeof(*tmp_tags) * num_tags;
> +     rbytes = sizeof(*reach_next) * (tnfa->num_states + 1);
> +@@ -221,10 +235,9 @@ tre_tnfa_run_parallel(const tre_tnfa_t *tnfa, const void *string,
> +       + (rbytes + xbytes * tnfa->num_states) * 2 + tbytes + pbytes;
> +
> +     /* Allocate the memory. */
> +-    buf = xmalloc((unsigned)total_bytes);
> ++    buf = calloc(total_bytes, 1);
> +     if (buf == NULL)
> +       return REG_ESPACE;
> +-    memset(buf, 0, (size_t)total_bytes);
> +
> +     /* Get the various pointers within tmp_buf (properly aligned). */
> +     tmp_tags = (void *)buf;
> +--
> +2.7.4
> +
> diff --git a/meta/recipes-core/musl/musl_git.bb b/meta/recipes-core/musl/musl_git.bb
> index c07101b..1ee56b6 100644
> --- a/meta/recipes-core/musl/musl_git.bb
> +++ b/meta/recipes-core/musl/musl_git.bb
> @@ -11,6 +11,7 @@ PV = "1.1.15+git${SRCPV}"
>
>  SRC_URI = "git://git.musl-libc.org/musl \
>             file://0001-Make-dynamic-linker-a-relative-symlink-to-libc.patch \
> +           file://CVE-2016-8859.patch \
>            "
>
>  S = "${WORKDIR}/git"
> --
> 2.7.4
>
> --
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