Description: "An exploitable signed comparison vulnerability exists in the ARMv7 memcpy() implementation of GNU glibc 2.30.9000. Calling memcpy() (on ARMv7 targets that utilize the GNU glibc implementation) with a negative value for the 'num' parameter results in a signed comparison vulnerability. If an attacker underflows the 'num' parameter to memcpy(), this vulnerability could lead to undefined behavior such as writing to out-of-bounds memory and potentially remote code execution. Furthermore, this memcpy() implementation allows for program execution to continue in scenarios where a segmentation fault or crash should have occurred. The dangers occur in that subsequent execution and iterations of this code will be executed with this corrupted data." It's not not clear that upstream actually agree it's a security bug. They have not formally disputed the CVE though.
this got fixed upstream by these two commits: https://sourceware.org/git/?p=glibc.git;a=patch;h=eec0f4218cda936a6ab8f543e90b96b196df3fc2 https://sourceware.org/git/?p=glibc.git;a=patch;h=eca1b233322914d9013f3ee4aabecaadc9245abd found via https://sourceware.org/bugzilla/show_bug.cgi?id=25620#c25 they apply to glibc-2.30-r8 , but I could imagine glibc-2.31-r3 being the better place to backport this since 2.30 is already stable
(In reply to tt_1 from comment #1) > this got fixed upstream by these two commits: These commits only added tests. The vulnerability was really fixed only recently: https://sourceware.org/bugzilla/show_bug.cgi?id=25620#c27
this got fixed in glibc-2.31 patchset8: sys-libs/glibc: 2.31 bump to patchset 8, finally stable candidate * arm: fix for CVE-2020-6096 * en_US: minimize changes to date_fmt (backport from 2.32) * x86-64: fix avx2 strncmp offset compare condition check * ia64: fix miscompilation on gcc-10
Thanks both.
The bug has been referenced in the following commit(s): https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=25382c826776a6af264da6af0153022bc30487ff commit 25382c826776a6af264da6af0153022bc30487ff Author: Andreas K. Hüttel <dilfridge@gentoo.org> AuthorDate: 2020-10-30 19:27:56 +0000 Commit: Andreas K. Hüttel <dilfridge@gentoo.org> CommitDate: 2020-10-30 19:29:02 +0000 package.mask: extend glibc mask to <2.31-r6 Bug: https://bugs.gentoo.org/717058 Signed-off-by: Andreas K. Hüttel <dilfridge@gentoo.org> profiles/package.mask | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
All masked. Security please proceed. No cleanup.
This issue was resolved and addressed in GLSA 202101-20 at https://security.gentoo.org/glsa/202101-20 by GLSA coordinator Aaron Bauman (b-man).
