On Wed, Oct 19, 2016 at 6:00 PM, Armin Kuster wrote:
> From: Armin Kuster
>
> 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
> ---
> 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 000..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
> +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
> +
> +---
> + 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
> + #include
> + #include
> ++#include
> +
> + #include
> +
> +@@ -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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