* sanity checks belong before risky operation, not after it
* don't quit as soon as we'd found an entry
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
new helper: dir_relax(inode). Call when you are in location that will
_not_ be invalidated by directory modifications (block boundary, in case
of ext*). Returns whether the directory has survived (dropping i_mutex
allows rmdir to kill the sucker; if it returns false to us, ->iterate()
is obviously done)
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
New method - ->iterate(file, ctx). That's the replacement for ->readdir();
it takes callback from ctx->actor, uses ctx->pos instead of file->f_pos and
calls dir_emit(ctx, ...) instead of filldir(data, ...). It does *not*
update file->f_pos (or look at it, for that matter); iterate_dir() does the
update.
Note that dir_emit() takes the offset from ctx->pos (and eventually
filldir_t will lose that argument).
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
iterate_dir(): new helper, replacing vfs_readdir().
struct dir_context: contains the readdir callback (and will get more stuff
in it), embedded into whatever data that callback wants to deal with;
eventually, we'll be passing it to ->readdir() replacement instead of
(data,filldir) pair.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no
mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are
in the middle of 'ubifs_readdir()'.
This means that 'file->private_data' can be freed while 'ubifs_readdir()' uses
it, and this is a very bad bug: not only 'ubifs_readdir()' can return garbage,
but this may corrupt memory and lead to all kinds of problems like crashes an
security holes.
This patch fixes the problem by using the 'file->f_version' field, which
'->llseek()' always unconditionally sets to zero. We set it to 1 in
'ubifs_readdir()' and whenever we detect that it became 0, we know there was a
seek and it is time to clear the state saved in 'file->private_data'.
I tested this patch by writing a user-space program which runds readdir and
seek in parallell. I could easily crash the kernel without these patches, but
could not crash it with these patches.
Cc: stable@vger.kernel.org
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Al Viro pointed me to the fact that '->readdir()' and '->llseek()' have no
mutual exclusion, which means the 'ubifs_dir_llseek()' can be run while we are
in the middle of 'ubifs_readdir()'.
First of all, this means that 'file->private_data' can be freed while
'ubifs_readdir()' uses it. But this particular patch does not fix the problem.
This patch is only a preparation, and the fix will follow next.
In this patch we make 'ubifs_readdir()' stop using 'file->f_pos' directly,
because 'file->f_pos' can be changed by '->llseek()' at any point. This may
lead 'ubifs_readdir()' to returning inconsistent data: directory entry names
may correspond to incorrect file positions.
So here we introduce a local variable 'pos', read 'file->f_pose' once at very
the beginning, and then stick to 'pos'. The result of this is that when
'ubifs_dir_llseek()' changes 'file->f_pos' while we are in the middle of
'ubifs_readdir()', the latter "wins".
Cc: stable@vger.kernel.org
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Tested-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
dump_seek() does SEEK_CUR, not SEEK_SET; native binfmt_aout
handles it correctly (seeks by PAGE_SIZE - sizeof(struct user),
getting the current position to PAGE_SIZE), compat one seeks
by PAGE_SIZE and ends up at PAGE_SIZE + already written...
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
When you copy some code, you are supposed to read it. If nothing else,
there's a chance to spot and fix an obvious bug instead of sharing it...
X-Song: "I Got It From Agnes", by Tom Lehrer
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[ Tom Lehrer? You're dating yourself, Al ]
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Another week, another batch of fixes for arm-soc platforms.
Again, nothing controversial. A few more than would be ideal, but all
are valid fixes. In particular the prima2 panic patch is critical since
it fixes a problem where multiplatform kernels panic on all but prima2
hardware.
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Merge tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC fixes from Olof Johansson:
"These are a little later than I planned on since I got caught up with
handling merges for 3.11 most of the week.
Another week, another batch of fixes for arm-soc platforms.
Again, nothing controversial. A few more than would be ideal, but all
are valid fixes. In particular the prima2 panic patch is critical
since it fixes a problem where multiplatform kernels panic on all but
prima2 hardware."
* tag 'fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc:
ARM: SAMSUNG: pm: Adjust for pinctrl- and DT-enabled platforms
ARM: prima2: fix incorrect panic usage
arm: mvebu: armada-xp-{gp,openblocks-ax3-4}: specify PCIe range
ARM: Kirkwood: handle mv88f6282 cpu in __kirkwood_variant().
ARM: omap3: clock: fix wrong container_of in clock36xx.c
ARM: dts: OMAP5: Fix missing PWM capability to timer nodes
ARM: dts: omap4-panda|sdp: Fix mux for twl6030 IRQ pin and msecure line
ARM: dts: AM33xx: Fix properties on gpmc node
arm: omap2: fix AM33xx hwmod infos for UART2
ARM: OMAP3: Fix iva2_pwrdm settings for 3703
Pull networking fixes from David Miller:
1) Fix RTNL locking in batman-adv, from Matthias Schiffer.
2) Don't allow non-passthrough macvlan devices to set NOPROMISC via
netlink, otherwise we can end up with corrupted promisc counter
values on the device. From Michael S Tsirkin.
3) Fix stmmac driver build with debugging defines enabled, from Dinh
Nguyen.
4) Make sure name string we give in socket address in AF_PACKET is NULL
terminated, from Daniel Borkmann.
5) Fix leaking of two uninitialized bytes of memory to userspace in
l2tp, from Guillaume Nault.
6) Clear IPCB(skb) before tunneling otherwise we touch dangling IP
options state and crash. From Saurabh Mohan.
7) Fix suspend/resume for davinci_mdio by using suspend_late and
resume_early. From Mugunthan V N.
8) Don't tag ip_tunnel_init_net and ip_tunnel_delete_net with
__net_{init,exit}, they can be called outside of those contexts.
From Eric Dumazet.
9) Fix RX length error in sh_eth driver, from Yoshihiro Shimoda.
10) Fix missing sctp_outq initialization in some code paths of SCTP
stack, from Neil Horman.
* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (21 commits)
sctp: fully initialize sctp_outq in sctp_outq_init
netiucv: Hold rtnl between name allocation and device registration.
tulip: Properly check dma mapping result
net: sh_eth: fix incorrect RX length error if R8A7740
ip_tunnel: remove __net_init/exit from exported functions
drivers: net: davinci_mdio: restore mdio clk divider in mdio resume
drivers: net: davinci_mdio: moving mdio resume earlier than cpsw ethernet driver
net/ipv4: ip_vti clear skb cb before tunneling.
tg3: Wait for boot code to finish after power on
l2tp: Fix sendmsg() return value
l2tp: Fix PPP header erasure and memory leak
bonding: fix igmp_retrans type and two related races
bonding: reset master mac on first enslave failure
packet: packet_getname_spkt: make sure string is always 0-terminated
net: ethernet: stmicro: stmmac: Fix compile error when STMMAC_XMIT_DEBUG used
be2net: Fix 32-bit DMA Mask handling
xen-netback: don't de-reference vif pointer after having called xenvif_put()
macvlan: don't touch promisc without passthrough
batman-adv: Don't handle address updates when bla is disabled
batman-adv: forward late OGMs from best next hop
...
Al Viro