From 97700a34f36721b11a754cf37a1cc40695ece1fd Mon Sep 17 00:00:00 2001 From: "H.J. Lu" Date: Mon, 21 Jan 2019 11:23:59 -0800 Subject: x86-64 memchr/wmemchr: Properly handle the length parameter [BZ# 24097] On x32, the size_t parameter may be passed in the lower 32 bits of a 64-bit register with the non-zero upper 32 bits. The string/memory functions written in assembly can only use the lower 32 bits of a 64-bit register as length or must clear the upper 32 bits before using the full 64-bit register for length. This pach fixes memchr/wmemchr for x32. Tested on x86-64 and x32. On x86-64, libc.so is the same with and withou the fix. [BZ# 24097] CVE-2019-6488 * sysdeps/x86_64/memchr.S: Use RDX_LP for length. Clear the upper 32 bits of RDX register. * sysdeps/x86_64/multiarch/memchr-avx2.S: Likewise. * sysdeps/x86_64/x32/Makefile (tests): Add tst-size_t-memchr and tst-size_t-wmemchr. * sysdeps/x86_64/x32/test-size_t.h: New file. * sysdeps/x86_64/x32/tst-size_t-memchr.c: Likewise. * sysdeps/x86_64/x32/tst-size_t-wmemchr.c: Likewise. --- NEWS | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'NEWS') diff --git a/NEWS b/NEWS index cc20102fda..7b3af113bf 100644 --- a/NEWS +++ b/NEWS @@ -101,6 +101,12 @@ Security related changes: denial of service due to resource exhaustion when processing getaddrinfo calls with crafted host names. Reported by Guido Vranken. + CVE-2019-6488: On x32, the size_t parameter may be passed in the lower + 32 bits of a 64-bit register with with non-zero upper 32 bit. When it + happened, accessing the 32-bit size_t value as the full 64-bit register + in the assembly string/memory functions would cause a buffer overflow. + Reported by H.J. Lu. + The following bugs are resolved with this release: [The release manager will add the list generated by -- cgit v1.2.3