kernel/linux.git/lib, branch v3.18.76

mpi: Fix NULL ptr dereference in mpi_powm() [ver #3]

2017-10-08T08:11:22+00:00

commit f5527fffff3f002b0a6b376163613b82f69de073 upstream. 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 Signed-off-by: James Morris Signed-off-by: Greg Kroah-Hartman

lib: bitmap: add alignment offset for bitmap_find_next_zero_area()

2017-09-02T05:05:45+00:00

commit 5e19b013f55a884c59a14391b22138899d1cc4cc upstream. Add a bitmap_find_next_zero_area_off() function which works like bitmap_find_next_zero_area() function except it allows an offset to be specified when alignment is checked. This lets caller request a bit such that its number plus the offset is aligned according to the mask. [gregory.0xf0@gmail.com: Retrieved from https://patchwork.linuxtv.org/patch/6254/ and updated documentation] Signed-off-by: Michal Nazarewicz Signed-off-by: Kyungmin Park Signed-off-by: Marek Szyprowski Signed-off-by: Gregory Fong Cc: Joonsoo Kim Cc: Kukjin Kim Cc: Laurent Pinchart Cc: Laura Abbott Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

lib/Kconfig.debug: fix frv build failure

2017-08-11T16:30:16+00:00

[ Upstream commit da0510c47519fe0999cffe316e1d370e29f952be ] The build of frv allmodconfig was failing with the errors like: /tmp/cc0JSPc3.s: Assembler messages: /tmp/cc0JSPc3.s:1839: Error: symbol `.LSLT0' is already defined /tmp/cc0JSPc3.s:1842: Error: symbol `.LASLTP0' is already defined /tmp/cc0JSPc3.s:1969: Error: symbol `.LELTP0' is already defined /tmp/cc0JSPc3.s:1970: Error: symbol `.LELT0' is already defined Commit 866ced950bcd ("kbuild: Support split debug info v4") introduced splitting the debug info and keeping that in a separate file. Somehow, the frv-linux gcc did not like that and I am guessing that instead of splitting it started copying. The first report about this is at: https://lists.01.org/pipermail/kbuild-all/2015-July/010527.html. I will try and see if this can work with frv and if still fails I will open a bug report with gcc. But meanwhile this is the easiest option to solve build failure of frv. Fixes: 866ced950bcd ("kbuild: Support split debug info v4") Link: http://lkml.kernel.org/r/1482062348-5352-1-git-send-email-sudipm.mukherjee@gmail.com Signed-off-by: Sudip Mukherjee Reported-by: Fengguang Wu Cc: Andi Kleen Cc: David Howells Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman

strscpy: zero any trailing garbage bytes in the destination

2017-08-11T16:30:09+00:00

commit 990486c8af044f89bddfbde1d1cf9fde449bedbf upstream. It's possible that the destination can be shadowed in userspace (as, for example, the perf buffers are now). So we should take care not to leak data that could be inspected by userspace. Signed-off-by: Chris Metcalf Signed-off-by: Greg Kroah-Hartman

string: provide strscpy()

2017-08-11T16:30:09+00:00

commit 30035e45753b708e7d47a98398500ca005e02b86 upstream. The strscpy() API is intended to be used instead of strlcpy(), and instead of most uses of strncpy(). - Unlike strlcpy(), it doesn't read from memory beyond (src + size). - Unlike strlcpy() or strncpy(), the API provides an easy way to check for destination buffer overflow: an -E2BIG error return value. - The provided implementation is robust in the face of the source buffer being asynchronously changed during the copy, unlike the current implementation of strlcpy(). - Unlike strncpy(), the destination buffer will be NUL-terminated if the string in the source buffer is too long. - Also unlike strncpy(), the destination buffer will not be updated beyond the NUL termination, avoiding strncpy's behavior of zeroing the entire tail end of the destination buffer. (A memset() after the strscpy() can be used if this behavior is desired.) - The implementation should be reasonably performant on all platforms since it uses the asm/word-at-a-time.h API rather than simple byte copy. Kernel-to-kernel string copy is not considered to be performance critical in any case. Signed-off-by: Chris Metcalf Signed-off-by: Greg Kroah-Hartman

lib/cmdline.c: fix get_options() overflow while parsing ranges

2017-06-29T07:12:23+00:00

commit a91e0f680bcd9e10c253ae8b62462a38bd48f09f upstream. When using get_options() it's possible to specify a range of numbers, like 1-100500. The problem is that it doesn't track array size while calling internally to get_range() which iterates over the range and fills the memory with numbers. Link: http://lkml.kernel.org/r/2613C75C-B04D-4BFF-82A6-12F97BA0F620@gmail.com Signed-off-by: Ilya V. Matveychikov Cc: Jonathan Corbet Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman

usercopy: Adjust tests to deal with SMAP/PAN

2017-06-14T10:54:20+00:00

commit f5f893c57e37ca730808cb2eee3820abd05e7507 upstream. Under SMAP/PAN/etc, we cannot write directly to userspace memory, so this rearranges the test bytes to get written through copy_to_user(). Additionally drops the bad copy_from_user() test that would trigger a memcpy() against userspace on failure. [arnd: the test module was added in 3.14, and this backported patch should apply cleanly on all version from 3.14 to 4.10. The original patch was in 4.11 on top of a context change I saw the bug triggered with kselftest on a 4.4.y stable kernel] Signed-off-by: Kees Cook Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman

KEYS: Fix ASN.1 indefinite length object parsing

2017-05-20T12:18:43+00:00

commit 23c8a812dc3c621009e4f0e5342aa4e2ede1ceaa upstream. This fixes CVE-2016-0758. In the ASN.1 decoder, when the length field of an ASN.1 value is extracted, it isn't validated against the remaining amount of data before being added to the cursor. With a sufficiently large size indicated, the check: datalen - dp < 2 may then fail due to integer overflow. Fix this by checking the length indicated against the amount of remaining data in both places a definite length is determined. Whilst we're at it, make the following changes: (1) Check the maximum size of extended length does not exceed the capacity of the variable it's being stored in (len) rather than the type that variable is assumed to be (size_t). (2) Compare the EOC tag to the symbolic constant ASN1_EOC rather than the integer 0. (3) To reduce confusion, move the initialisation of len outside of: for (len = 0; n > 0; n--) { since it doesn't have anything to do with the loop counter n. Signed-off-by: David Howells Reviewed-by: Mimi Zohar Acked-by: David Woodhouse Acked-by: Peter Jones Signed-off-by: Amit Pundir Signed-off-by: Greg Kroah-Hartman

ASN.1: Fix non-match detection failure on data overrun

2017-05-20T12:18:43+00:00

commit 0d62e9dd6da45bbf0f33a8617afc5fe774c8f45f upstream. If the ASN.1 decoder is asked to parse a sequence of objects, non-optional matches get skipped if there's no more data to be had rather than a data-overrun error being reported. This is due to the code segment that decides whether to skip optional matches (ie. matches that could get ignored because an element is marked OPTIONAL in the grammar) due to a lack of data also skips non-optional elements if the data pointer has reached the end of the buffer. This can be tested with the data decoder for the new RSA akcipher algorithm that takes three non-optional integers. Currently, it skips the last integer if there is insufficient data. Without the fix, #defining DEBUG in asn1_decoder.c will show something like: next_op: pc=0/13 dp=0/270 C=0 J=0 - match? 30 30 00 - TAG: 30 266 CONS next_op: pc=2/13 dp=4/270 C=1 J=0 - match? 02 02 00 - TAG: 02 257 - LEAF: 257 next_op: pc=5/13 dp=265/270 C=1 J=0 - match? 02 02 00 - TAG: 02 3 - LEAF: 3 next_op: pc=8/13 dp=270/270 C=1 J=0 next_op: pc=11/13 dp=270/270 C=1 J=0 - end cons t=4 dp=270 l=270/270 The next_op line for pc=8/13 should be followed by a match line. This is not exploitable for X.509 certificates by means of shortening the message and fixing up the ASN.1 CONS tags because: (1) The relevant records being built up are cleared before use. (2) If the message is shortened sufficiently to remove the public key, the ASN.1 parse of the RSA key will fail quickly due to a lack of data. (3) Extracted signature data is either turned into MPIs (which cope with a 0 length) or is simpler integers specifying algoritms and suchlike (which can validly be 0); and (4) The AKID and SKID extensions are optional and their removal is handled without risking passing a NULL to asymmetric_key_generate_id(). (5) If the certificate is truncated sufficiently to remove the subject, issuer or serialNumber then the ASN.1 decoder will fail with a 'Cons stack underflow' return. This is not exploitable for PKCS#7 messages by means of removal of elements from such a message from the tail end of a sequence: (1) Any shortened X.509 certs embedded in the PKCS#7 message are survivable as detailed above. (2) The message digest content isn't used if it shows a NULL pointer, similarly, the authattrs aren't used if that shows a NULL pointer. (3) A missing signature results in a NULL MPI - which the MPI routines deal with. (4) If data is NULL, it is expected that the message has detached content and that is handled appropriately. (5) If the serialNumber is excised, the unconditional action associated with it will pick up the containing SEQUENCE instead, so no NULL pointer will be seen here. If both the issuer and the serialNumber are excised, the ASN.1 decode will fail with an 'Unexpected tag' return. In either case, there's no way to get to asymmetric_key_generate_id() with a NULL pointer. (6) Other fields are decoded to simple integers. Shortening the message to omit an algorithm ID field will cause checks on this to fail early in the verification process. This can also be tested by snipping objects off of the end of the ASN.1 stream such that mandatory tags are removed - or even from the end of internal SEQUENCEs. If any mandatory tag is missing, the error EBADMSG *should* be produced. Without this patch ERANGE or ENOPKG might be produced or the parse may apparently succeed, perhaps with ENOKEY or EKEYREJECTED being produced later, depending on what gets snipped. Just snipping off the final BIT_STRING or OCTET_STRING from either sample should be a start since both are mandatory and neither will cause an EBADMSG without the patches Reported-by: Marcel Holtmann Signed-off-by: David Howells Tested-by: Marcel Holtmann Reviewed-by: David Woodhouse Signed-off-by: Amit Pundir Signed-off-by: Greg Kroah-Hartman

cpumask_set_cpu_local_first => cpumask_local_spread, lament

2017-05-08T05:44:12+00:00

commit f36963c9d3f6f415732710da3acdd8608a9fa0e5 upstream. da91309e0a7e (cpumask: Utility function to set n'th cpu...) created a genuinely weird function. I never saw it before, it went through DaveM. (He only does this to make us other maintainers feel better about our own mistakes.) cpumask_set_cpu_local_first's purpose is say "I need to spread things across N online cpus, choose the ones on this numa node first"; you call it in a loop. It can fail. One of the two callers ignores this, the other aborts and fails the device open. It can fail in two ways: allocating the off-stack cpumask, or through a convoluted codepath which AFAICT can only occur if cpu_online_mask changes. Which shouldn't happen, because if cpu_online_mask can change while you call this, it could return a now-offline cpu anyway. It contains a nonsensical test "!cpumask_of_node(numa_node)". This was drawn to my attention by Geert, who said this causes a warning on Sparc. It sets a single bit in a cpumask instead of returning a cpu number, because that's what the callers want. It could be made more efficient by passing the previous cpu rather than an index, but that would be more invasive to the callers. [backporting for 3.18: only two callers exist, otherwise no change. The same warning shows up for "!cpumask_of_node()", and I thought about just addressing the warning, but using the whole fix seemed better in the end as one of the two callers also lacks the error handling] Fixes: da91309e0a7e8966d916a74cce42ed170fde06bf Signed-off-by: Rusty Russell (then rebased) Tested-by: Amir Vadai Acked-by: Amir Vadai Acked-by: David S. Miller Signed-off-by: Arnd Bergmann Signed-off-by: Greg Kroah-Hartman