linux-stable.git/net/dns_resolver, branch linux-3.16.y

KEYS: DNS: fix parsing multiple options

2018-11-20T18:05:43+00:00

commit c604cb767049b78b3075497b80ebb8fd530ea2cc upstream.

My recent fix for dns_resolver_preparse() printing very long strings was
incomplete, as shown by syzbot which still managed to hit the
WARN_ONCE() in set_precision() by adding a crafted "dns_resolver" key:

    precision 50001 too large
    WARNING: CPU: 7 PID: 864 at lib/vsprintf.c:2164 vsnprintf+0x48a/0x5a0

The bug this time isn't just a printing bug, but also a logical error
when multiple options ("#"-separated strings) are given in the key
payload.  Specifically, when separating an option string into name and
value, if there is no value then the name is incorrectly considered to
end at the end of the key payload, rather than the end of the current
option.  This bypasses validation of the option length, and also means
that specifying multiple options is broken -- which presumably has gone
unnoticed as there is currently only one valid option anyway.

A similar problem also applied to option values, as the kstrtoul() when
parsing the "dnserror" option will read past the end of the current
option and into the next option.

Fix these bugs by correctly computing the length of the option name and
by copying the option value, null-terminated, into a temporary buffer.

Reproducer for the WARN_ONCE() that syzbot hit:

    perl -e 'print "#A#", "\0" x 50000' | keyctl padd dns_resolver desc @s

Reproducer for "dnserror" option being parsed incorrectly (expected
behavior is to fail when seeing the unknown option "foo", actual
behavior was to read the dnserror value as "1#foo" and fail there):

    perl -e 'print "#dnserror=1#foo\0"' | keyctl padd dns_resolver desc @s

Reported-by: syzbot 
Fixes: 4a2d789267e0 ("DNS: If the DNS server returns an error, allow that to be cached [ver #2]")
Signed-off-by: Eric Biggers 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

KEYS: DNS: limit the length of option strings

2018-10-21T07:45:30+00:00

commit 9c438d7a3a52dcc2b9ed095cb87d3a5e83cf7e60 upstream.

Adding a dns_resolver key whose payload contains a very long option name
resulted in that string being printed in full.  This hit the WARN_ONCE()
in set_precision() during the printk(), because printk() only supports a
precision of up to 32767 bytes:

    precision 1000000 too large
    WARNING: CPU: 0 PID: 752 at lib/vsprintf.c:2189 vsnprintf+0x4bc/0x5b0

Fix it by limiting option strings (combined name + value) to a much more
reasonable 128 bytes.  The exact limit is arbitrary, but currently the
only recognized option is formatted as "dnserror=%lu" which fits well
within this limit.

Also ratelimit the printks.

Reproducer:

    perl -e 'print "#", "A" x 1000000, "\x00"' | keyctl padd dns_resolver desc @s

This bug was found using syzkaller.

Reported-by: Mark Rutland 
Fixes: 4a2d789267e0 ("DNS: If the DNS server returns an error, allow that to be cached [ver #2]")
Signed-off-by: Eric Biggers 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.16:
 - Also stop logging the key serial number
 - Include  directly]
Signed-off-by: Ben Hutchings

dns_resolver: Null-terminate the right string

2014-07-21T05:33:32+00:00

*_result[len] is parsed as *(_result[len]) which is not at all what we
want to touch here.

Signed-off-by: Ben Hutchings 
Fixes: 84a7c0b1db1c ("dns_resolver: assure that dns_query() result is null-terminated")
Signed-off-by: David S. Miller

Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net

2014-06-11T23:02:55+00:00

Conflicts:
	net/core/rtnetlink.c
	net/core/skbuff.c

Both conflicts were very simple overlapping changes.

Signed-off-by: David S. Miller

dns_resolver: assure that dns_query() result is null-terminated

2014-06-11T07:12:04+00:00

dns_query() credulously assumes that keys are null-terminated and
returns a copy of a memory block that is off by one.

Signed-off-by: Manuel Schölling 
Signed-off-by: David S. Miller

dns_resolver: Do not accept domain names longer than 255 chars

2014-06-05T07:05:53+00:00

According to RFC1035 "[...] the total length of a domain name (i.e.,
label octets and label length octets) is restricted to 255 octets or
less."

Signed-off-by: Manuel Schölling 
Signed-off-by: David S. Miller

net/*: Fix FSF address in file headers

2013-12-06T17:37:57+00:00

Several files refer to an old address for the Free Software Foundation
in the file header comment.  Resolve by replacing the address with
the URL  so that we do not have to keep
updating the header comments anytime the address changes.

CC: John Fastabend 
CC: Alex Duyck 
CC: Marcel Holtmann 
CC: Gustavo Padovan 
CC: Johan Hedberg 
CC: Jamal Hadi Salim 
Signed-off-by: Jeff Kirsher 
Signed-off-by: David S. Miller

net: strict_strtoul is obsolete, use kstrtoul instead

2013-07-12T23:09:14+00:00

patch found using checkpatch.pl

Signed-off-by: Cosmin Stanescu 
Signed-off-by: David S. Miller

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security

2012-12-16T23:40:50+00:00

Pull security subsystem updates from James Morris:
 "A quiet cycle for the security subsystem with just a few maintenance
  updates."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security:
  Smack: create a sysfs mount point for smackfs
  Smack: use select not depends in Kconfig
  Yama: remove locking from delete path
  Yama: add RCU to drop read locking
  drivers/char/tpm: remove tasklet and cleanup
  KEYS: Use keyring_alloc() to create special keyrings
  KEYS: Reduce initial permissions on keys
  KEYS: Make the session and process keyrings per-thread
  seccomp: Make syscall skipping and nr changes more consistent
  key: Fix resource leak
  keys: Fix unreachable code
  KEYS: Add payload preparsing opportunity prior to key instantiate or update

Merge branch 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux

2012-10-14T20:39:34+00:00

Pull module signing support from Rusty Russell:
 "module signing is the highlight, but it's an all-over David Howells frenzy..."

Hmm "Magrathea: Glacier signing key". Somebody has been reading too much HHGTTG.

* 'modules-next' of git://git.kernel.org/pub/scm/linux/kernel/git/rusty/linux: (37 commits)
  X.509: Fix indefinite length element skip error handling
  X.509: Convert some printk calls to pr_devel
  asymmetric keys: fix printk format warning
  MODSIGN: Fix 32-bit overflow in X.509 certificate validity date checking
  MODSIGN: Make mrproper should remove generated files.
  MODSIGN: Use utf8 strings in signer's name in autogenerated X.509 certs
  MODSIGN: Use the same digest for the autogen key sig as for the module sig
  MODSIGN: Sign modules during the build process
  MODSIGN: Provide a script for generating a key ID from an X.509 cert
  MODSIGN: Implement module signature checking
  MODSIGN: Provide module signing public keys to the kernel
  MODSIGN: Automatically generate module signing keys if missing
  MODSIGN: Provide Kconfig options
  MODSIGN: Provide gitignore and make clean rules for extra files
  MODSIGN: Add FIPS policy
  module: signature checking hook
  X.509: Add a crypto key parser for binary (DER) X.509 certificates
  MPILIB: Provide a function to read raw data into an MPI
  X.509: Add an ASN.1 decoder
  X.509: Add simple ASN.1 grammar compiler
  ...