diff --git a/debian/changelog b/debian/changelog index 28e5e38d8..6bab68293 100644 --- a/debian/changelog +++ b/debian/changelog @@ -233,6 +233,7 @@ linux (4.8.11-1) UNRELEASED; urgency=medium * fs: Give dentry to inode_change_ok() instead of inode * fs: Avoid premature clearing of capabilities (CVE-2015-1350) (Closes: #770492) + * mpi: Fix NULL ptr dereference in mpi_powm() (CVE-2016-8650) [ Ben Hutchings ] * [arm64] Enable more drivers for X-Gene (Really closes: #840061): diff --git a/debian/patches/bugfix/all/mpi-Fix-NULL-ptr-dereference-in-mpi_powm-ver-3.patch b/debian/patches/bugfix/all/mpi-Fix-NULL-ptr-dereference-in-mpi_powm-ver-3.patch new file mode 100644 index 000000000..ae2e61a36 --- /dev/null +++ b/debian/patches/bugfix/all/mpi-Fix-NULL-ptr-dereference-in-mpi_powm-ver-3.patch @@ -0,0 +1,100 @@ +From: Andrey Ryabinin +Date: Thu, 24 Nov 2016 13:23:10 +0000 +Subject: mpi: Fix NULL ptr dereference in mpi_powm() [ver #3] +Origin: https://git.kernel.org/linus/f5527fffff3f002b0a6b376163613b82f69de073 + +This fixes CVE-2016-8650. + +If mpi_powm() is given a zero exponent, it wants to immediately return +either 1 or 0, depending on the modulus. However, if the result was +initalised with zero limb space, no limbs space is allocated and a +NULL-pointer exception ensues. + +Fix this by allocating a minimal amount of limb space for the result when +the 0-exponent case when the result is 1 and not touching the limb space +when the result is 0. + +This affects the use of RSA keys and X.509 certificates that carry them. + +BUG: unable to handle kernel NULL pointer dereference at (null) +IP: [] mpi_powm+0x32/0x7e6 +PGD 0 +Oops: 0002 [#1] SMP +Modules linked in: +CPU: 3 PID: 3014 Comm: keyctl Not tainted 4.9.0-rc6-fscache+ #278 +Hardware name: ASUS All Series/H97-PLUS, BIOS 2306 10/09/2014 +task: ffff8804011944c0 task.stack: ffff880401294000 +RIP: 0010:[] [] mpi_powm+0x32/0x7e6 +RSP: 0018:ffff880401297ad8 EFLAGS: 00010212 +RAX: 0000000000000000 RBX: ffff88040868bec0 RCX: ffff88040868bba0 +RDX: ffff88040868b260 RSI: ffff88040868bec0 RDI: ffff88040868bee0 +RBP: ffff880401297ba8 R08: 0000000000000000 R09: 0000000000000000 +R10: 0000000000000047 R11: ffffffff8183b210 R12: 0000000000000000 +R13: ffff8804087c7600 R14: 000000000000001f R15: ffff880401297c50 +FS: 00007f7a7918c700(0000) GS:ffff88041fb80000(0000) knlGS:0000000000000000 +CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 +CR2: 0000000000000000 CR3: 0000000401250000 CR4: 00000000001406e0 +Stack: + ffff88040868bec0 0000000000000020 ffff880401297b00 ffffffff81376cd4 + 0000000000000100 ffff880401297b10 ffffffff81376d12 ffff880401297b30 + ffffffff81376f37 0000000000000100 0000000000000000 ffff880401297ba8 +Call Trace: + [] ? __sg_page_iter_next+0x43/0x66 + [] ? sg_miter_get_next_page+0x1b/0x5d + [] ? sg_miter_next+0x17/0xbd + [] ? mpi_read_raw_from_sgl+0xf2/0x146 + [] rsa_verify+0x9d/0xee + [] ? pkcs1pad_sg_set_buf+0x2e/0xbb + [] pkcs1pad_verify+0xc0/0xe1 + [] public_key_verify_signature+0x1b0/0x228 + [] x509_check_for_self_signed+0xa1/0xc4 + [] x509_cert_parse+0x167/0x1a1 + [] x509_key_preparse+0x21/0x1a1 + [] asymmetric_key_preparse+0x34/0x61 + [] key_create_or_update+0x145/0x399 + [] SyS_add_key+0x154/0x19e + [] do_syscall_64+0x80/0x191 + [] entry_SYSCALL64_slow_path+0x25/0x25 +Code: 56 41 55 41 54 53 48 81 ec a8 00 00 00 44 8b 71 04 8b 42 04 4c 8b 67 18 45 85 f6 89 45 80 0f 84 b4 06 00 00 85 c0 75 2f 41 ff ce <49> c7 04 24 01 00 00 00 b0 01 75 0b 48 8b 41 18 48 83 38 01 0f +RIP [] mpi_powm+0x32/0x7e6 + RSP +CR2: 0000000000000000 +---[ end trace d82015255d4a5d8d ]--- + +Basically, this is a backport of a libgcrypt patch: + + http://git.gnupg.org/cgi-bin/gitweb.cgi?p=libgcrypt.git;a=patch;h=6e1adb05d290aeeb1c230c763970695f4a538526 + +Fixes: cdec9cb5167a ("crypto: GnuPG based MPI lib - source files (part 1)") +Signed-off-by: Andrey Ryabinin +Signed-off-by: David Howells +cc: Dmitry Kasatkin +cc: linux-ima-devel@lists.sourceforge.net +cc: stable@vger.kernel.org +Signed-off-by: James Morris +--- + lib/mpi/mpi-pow.c | 7 ++++++- + 1 file changed, 6 insertions(+), 1 deletion(-) + +diff --git a/lib/mpi/mpi-pow.c b/lib/mpi/mpi-pow.c +index 5464c87..e24388a 100644 +--- a/lib/mpi/mpi-pow.c ++++ b/lib/mpi/mpi-pow.c +@@ -64,8 +64,13 @@ int mpi_powm(MPI res, MPI base, MPI exp, MPI mod) + if (!esize) { + /* Exponent is zero, result is 1 mod MOD, i.e., 1 or 0 + * depending on if MOD equals 1. */ +- rp[0] = 1; + res->nlimbs = (msize == 1 && mod->d[0] == 1) ? 0 : 1; ++ if (res->nlimbs) { ++ if (mpi_resize(res, 1) < 0) ++ goto enomem; ++ rp = res->d; ++ rp[0] = 1; ++ } + res->sign = 0; + goto leave; + } +-- +2.1.4 + diff --git a/debian/patches/series b/debian/patches/series index 2e51238a3..f09c1db61 100644 --- a/debian/patches/series +++ b/debian/patches/series @@ -98,6 +98,7 @@ bugfix/all/ceph-Propagate-dentry-down-to-inode_change_ok.patch bugfix/all/fuse-Propagate-dentry-down-to-inode_change_ok.patch bugfix/all/fs-Give-dentry-to-inode_change_ok-instead-of-inode.patch bugfix/all/fs-Avoid-premature-clearing-of-capabilities.patch +bugfix/all/mpi-Fix-NULL-ptr-dereference-in-mpi_powm-ver-3.patch # ABI maintenance