This allows user to print a given buffer as an escaped string. The
rules are applied according to an optional mix of flags provided by
additional format letters.
For example, if the given buffer is:
1b 62 20 5c 43 07 22 90 0d 5d
The result strings would be:
%*pE "\eb \C\a"\220\r]"
%*pEhp "\x1bb \C\x07"\x90\x0d]"
%*pEa "\e\142\040\\\103\a\042\220\r\135"
Please, read Documentation/printk-formats.txt and lib/string_helpers.c
kernel documentation to get further information.
[akpm@linux-foundation.org: tidy up comment layout, per Joe]
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Suggested-by: Joe Perches <joe@perches.com>
Cc: "John W . Linville" <linville@tuxdriver.com>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This patch fix spelling typo found in DocBook/kernel-api.xml.
It is because the file is generated from the source comments,
I have to fix the comments in source codes.
Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Fixing 2 coccinelle warnings:
lib/vsprintf.c:2350:2-9: WARNING: Assignment of bool to 0/1
lib/vsprintf.c:2389:3-10: WARNING: Assignment of bool to 0/1
Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
All in-kernel users of %n in format strings have now been removed and
the %n directive is ignored. Remove the handling of %n so that it is
treated the same as any other invalid format string directive. Keep a
warning in place to deter new instances of %n in format strings.
Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Acked-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Sometimes we have a struct resource where we know the type (MEM/IO/etc.)
and the size, but we haven't assigned address space for it. The
IORESOURCE_UNSET flag is a way to indicate this situation. For these
"unset" resources, the start address is meaningless, so print only the
size, e.g.,
- pci 0000:0c:00.0: reg 184: [mem 0x00000000-0x00001fff 64bit]
+ pci 0000:0c:00.0: reg 184: [mem size 0x2000 64bit]
For %pr (printing with raw flags), we still print the address range,
because %pr is mostly used for debugging anyway.
Thanks to Fengguang Wu <fengguang.wu@intel.com> for suggesting
resource_size().
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This ignores %n in printf again, as was originally documented.
Implementing %n poses a greater security risk than utility, so it should
stay ignored. To help anyone attempting to use %n, a warning will be
emitted if it is encountered.
Based on an earlier patch by Joe Perches.
Because %n was designed to write to pointers on the stack, it has been
frequently used as an attack vector when bugs are found that leak
user-controlled strings into functions that ultimately process format
strings. While this class of bug can still be turned into an
information leak, removing %n eliminates the common method of elevating
such a bug into an arbitrary kernel memory writing primitive,
significantly reducing the danger of this class of bug.
For seq_file users that need to know the length of a written string for
padding, please see seq_setwidth() and seq_pad() instead.
Signed-off-by: Kees Cook <keescook@chromium.org>
Cc: Joe Perches <joe@perches.com>
Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: David Miller <davem@davemloft.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Some setuid binaries will allow reading of files which have read
permission by the real user id. This is problematic with files which
use %pK because the file access permission is checked at open() time,
but the kptr_restrict setting is checked at read() time. If a setuid
binary opens a %pK file as an unprivileged user, and then elevates
permissions before reading the file, then kernel pointer values may be
leaked.
This happens for example with the setuid pppd application on Ubuntu 12.04:
$ head -1 /proc/kallsyms
00000000 T startup_32
$ pppd file /proc/kallsyms
pppd: In file /proc/kallsyms: unrecognized option 'c1000000'
This will only leak the pointer value from the first line, but other
setuid binaries may leak more information.
Fix this by adding a check that in addition to the current process having
CAP_SYSLOG, that effective user and group ids are equal to the real ids.
If a setuid binary reads the contents of a file which uses %pK then the
pointer values will be printed as NULL if the real user is unprivileged.
Update the sysctl documentation to reflect the changes, and also correct
the documentation to state the kptr_restrict=0 is the default.
This is a only temporary solution to the issue. The correct solution is
to do the permission check at open() time on files, and to replace %pK
with a function which checks the open() time permission. %pK uses in
printk should be removed since no sane permission check can be done, and
instead protected by using dmesg_restrict.
Signed-off-by: Ryan Mallon <rmallon@gmail.com>
Cc: Kees Cook <keescook@chromium.org>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: Joe Perches <joe@perches.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
New formats: %p[dD][234]?. The next pointer is interpreted as struct dentry *
or struct file * resp. ('d' => dentry, 'D' => file) and the last component(s)
of pathname are printed (%pd => just the last one, %pd2 => the last two, etc.)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Pull networking updates from David Miller:
"This is a re-do of the net-next pull request for the current merge
window. The only difference from the one I made the other day is that
this has Eliezer's interface renames and the timeout handling changes
made based upon your feedback, as well as a few bug fixes that have
trickeled in.
Highlights:
1) Low latency device polling, eliminating the cost of interrupt
handling and context switches. Allows direct polling of a network
device from socket operations, such as recvmsg() and poll().
Currently ixgbe, mlx4, and bnx2x support this feature.
Full high level description, performance numbers, and design in
commit 0a4db187a9 ("Merge branch 'll_poll'")
From Eliezer Tamir.
2) With the routing cache removed, ip_check_mc_rcu() gets exercised
more than ever before in the case where we have lots of multicast
addresses. Use a hash table instead of a simple linked list, from
Eric Dumazet.
3) Add driver for Atheros CQA98xx 802.11ac wireless devices, from
Bartosz Markowski, Janusz Dziedzic, Kalle Valo, Marek Kwaczynski,
Marek Puzyniak, Michal Kazior, and Sujith Manoharan.
4) Support reporting the TUN device persist flag to userspace, from
Pavel Emelyanov.
5) Allow controlling network device VF link state using netlink, from
Rony Efraim.
6) Support GRE tunneling in openvswitch, from Pravin B Shelar.
7) Adjust SOCK_MIN_RCVBUF and SOCK_MIN_SNDBUF for modern times, from
Daniel Borkmann and Eric Dumazet.
8) Allow controlling of TCP quickack behavior on a per-route basis,
from Cong Wang.
9) Several bug fixes and improvements to vxlan from Stephen
Hemminger, Pravin B Shelar, and Mike Rapoport. In particular,
support receiving on multiple UDP ports.
10) Major cleanups, particular in the area of debugging and cookie
lifetime handline, to the SCTP protocol code. From Daniel
Borkmann.
11) Allow packets to cross network namespaces when traversing tunnel
devices. From Nicolas Dichtel.
12) Allow monitoring netlink traffic via AF_PACKET sockets, in a
manner akin to how we monitor real network traffic via ptype_all.
From Daniel Borkmann.
13) Several bug fixes and improvements for the new alx device driver,
from Johannes Berg.
14) Fix scalability issues in the netem packet scheduler's time queue,
by using an rbtree. From Eric Dumazet.
15) Several bug fixes in TCP loss recovery handling, from Yuchung
Cheng.
16) Add support for GSO segmentation of MPLS packets, from Simon
Horman.
17) Make network notifiers have a real data type for the opaque
pointer that's passed into them. Use this to properly handle
network device flag changes in arp_netdev_event(). From Jiri
Pirko and Timo Teräs.
18) Convert several drivers over to module_pci_driver(), from Peter
Huewe.
19) tcp_fixup_rcvbuf() can loop 500 times over loopback, just use a
O(1) calculation instead. From Eric Dumazet.
20) Support setting of explicit tunnel peer addresses in ipv6, just
like ipv4. From Nicolas Dichtel.
21) Protect x86 BPF JIT against spraying attacks, from Eric Dumazet.
22) Prevent a single high rate flow from overruning an individual cpu
during RX packet processing via selective flow shedding. From
Willem de Bruijn.
23) Don't use spinlocks in TCP md5 signing fast paths, from Eric
Dumazet.
24) Don't just drop GSO packets which are above the TBF scheduler's
burst limit, chop them up so they are in-bounds instead. Also
from Eric Dumazet.
25) VLAN offloads are missed when configured on top of a bridge, fix
from Vlad Yasevich.
26) Support IPV6 in ping sockets. From Lorenzo Colitti.
27) Receive flow steering targets should be updated at poll() time
too, from David Majnemer.
28) Fix several corner case regressions in PMTU/redirect handling due
to the routing cache removal, from Timo Teräs.
29) We have to be mindful of ipv4 mapped ipv6 sockets in
upd_v6_push_pending_frames(). From Hannes Frederic Sowa.
30) Fix L2TP sequence number handling bugs, from James Chapman."
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-next: (1214 commits)
drivers/net: caif: fix wrong rtnl_is_locked() usage
drivers/net: enic: release rtnl_lock on error-path
vhost-net: fix use-after-free in vhost_net_flush
net: mv643xx_eth: do not use port number as platform device id
net: sctp: confirm route during forward progress
virtio_net: fix race in RX VQ processing
virtio: support unlocked queue poll
net/cadence/macb: fix bug/typo in extracting gem_irq_read_clear bit
Documentation: Fix references to defunct linux-net@vger.kernel.org
net/fs: change busy poll time accounting
net: rename low latency sockets functions to busy poll
bridge: fix some kernel warning in multicast timer
sfc: Fix memory leak when discarding scattered packets
sit: fix tunnel update via netlink
dt:net:stmmac: Add dt specific phy reset callback support.
dt:net:stmmac: Add support to dwmac version 3.610 and 3.710
dt:net:stmmac: Allocate platform data only if its NULL.
net:stmmac: fix memleak in the open method
ipv6: rt6_check_neigh should successfully verify neigh if no NUD information are available
net: ipv6: fix wrong ping_v6_sendmsg return value
...
In order to avoid making code that deals with printing both, IPv4 and
IPv6 addresses, unnecessary complicated as for example ...
if (sa.sa_family == AF_INET6)
printk("... %pI6 ...", ..sin6_addr);
else
printk("... %pI4 ...", ..sin_addr.s_addr);
... it would be better to introduce a format specifier that can deal
with those kind of situations internally; just as we have a "struct
sockaddr" for generic mapping into "struct sockaddr_in" or "struct
sockaddr_in6" as e.g. done in "union sctp_addr". Then, we could
reduce the above statement into something like:
printk("... %pIS ..", &sockaddr);
In case our pointer is NULL, pointer() then deals with that already at
an earlier point in time internally. While we're at it, support for both
%piS/%pIS, where 'S' stands for sockaddr, comes (almost) for free.
Additionally to that, postfix specifiers 'p', 'f' and 's' are supported
as suggested and initially implemented in 2009 by Joe Perches [1].
Handling of those additional specifiers orientate on the initial RFC that
was proposed. Also we support IPv6 compressed format specified by 'c' and
various other IPv4 extensions as stated in the documentation part.
Likely, there are many other areas than just SCTP in the kernel to make
use of this extension as well.
[1] http://patchwork.ozlabs.org/patch/31480/
Signed-off-by: Daniel Borkmann <dborkman@redhat.com>
CC: Joe Perches <joe@perches.com>
CC: linux-kernel@vger.kernel.org
Signed-off-by: David S. Miller <davem@davemloft.net>
print_symbol takes a long and converts it to a function
name and offset. %pS does something similar, but doesn't
translate the address via __builtin_extract_return_addr.
%pSR does the translation.
This will enable replacing multiple calls like
printk(...);
printk_symbol(addr);
printk("\n");
with a single non-interleavable in dmesg
printk("... %pSR\n", (void *)addr);
Update documentation too.
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
This is another step towards better standard conformance. Rather than
adding a local buffer to store the specified portion of the string (with
the need to enforce an arbitrary maximum supported width to limit the
buffer size), do a maximum width conversion and then drop as much of it as
is necessary to meet the caller's request.
Also fail on negative field widths.
Uses the deprecated simple_strto*() functions because kstrtoXX() fail on
non-zero terminated strings.
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Documentation/printk-formats.txt says to use %zd for a ssize_t argument
and some drivers do. Unfortunately this prints a positive number for
negative values eg:
tpm_tis 70030000.tpm_tis: tpm_transmit: tpm_send: error 4294967234
Add a case to va_args a ssize_t type if the interpretation should be
signed.
Tested on PPC32.
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Xen's pciback points out a couple of deficiencies with vsscanf()'s
standard conformance:
- Trailing character matching cannot be checked by the caller: With a
format string of "(%x:%x.%x) %n" absence of the closing parenthesis
cannot be checked, as input of "(00:00.0)" doesn't cause the %n to be
evaluated (because of the code not skipping white space before the
trailing %n).
- The parameter corresponding to a trailing %n could get filled even if
there was a matching error: With a format string of "(%x:%x.%x)%n",
input of "(00:00.0]" would still fill the respective variable pointed to
(and hence again make the mismatch non-detectable by the caller).
This patch aims at fixing those, but leaves other non-conforming aspects
of it untouched, among them these possibly relevant ones:
- improper handling of the assignment suppression character '*' (blindly
discarding all succeeding non-white space from the format and input
strings),
- not honoring conversion specifiers for %n, - not recognizing the C99
conversion specifier 't' (recognized by vsprintf()).
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
If you're going to have a conditional branch after each 32x32->64-bit
multiply, might as well shrink the code and make it a loop.
This also avoids using the long multiply for small integers.
(This leaves the comments in a confusing state, but that's a separate
patch to make review easier.)
Signed-off-by: George Spelvin <linux@horizon.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Cc: Rabin Vincent <rabin@rab.in>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
There are many places in the kernel where the drivers print small buffers
as a hex string. This patch adds a support of the variable width buffer
to print it as a hex string with a delimiter. The idea came from Pavel
Roskin here: http://www.digipedia.pl/usenet/thread/18835/17449/
Sample output of
pr_info("buf[%d:%d] %*phC\n", from, len, len, &buf[from]);
could be look like this:
[ 0.726130] buf[51:8] e8:16:b6:ef:e3:74:45:6e
[ 0.750736] buf[59:15] 31:81:b8:3f:35:49:06:ae:df:32:06:05:4a:af:55
[ 0.757602] buf[17:5] ac:16:d5:2c:ef
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
