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[PATCH 4.0 046/148] lib: Fix strnlen_user() to not touch memory after specified maximum

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4.0-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Jan Kara <jack@suse.cz>

commit f18c34e483ff6b1d9866472221e4015b3a4698e4 upstream.

If the specified maximum length of the string is a multiple of unsigned
long, we would load one long behind the specified maximum.  If that
happens to be in a next page, we can hit a page fault although we were
not expected to.

Fix the off-by-one bug in the test whether we are at the end of the
specified range.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 lib/strnlen_user.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/lib/strnlen_user.c
+++ b/lib/strnlen_user.c
@@ -57,7 +57,8 @@ static inline long do_strnlen_user(const
 			return res + find_zero(data) + 1 - align;
 		}
 		res += sizeof(unsigned long);
-		if (unlikely(max < sizeof(unsigned long)))
+		/* We already handled 'unsigned long' bytes. Did we do it all ? */
+		if (unlikely(max <= sizeof(unsigned long)))
 			break;
 		max -= sizeof(unsigned long);
 		if (unlikely(__get_user(c,(unsigned long __user *)(src+res))))


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[PATCH 4.0 000/148] 4.0.5-stable review Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 021/148] mfd: da9052: Fix broken regulator probe Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 061/148] ASoC: wm8994: correct BCLK DIV 348 to 384 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 026/148] hwmon: (ntc_thermistor) Ensure iio channel is of type IIO_VOLTAGE Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 048/148] module: Call module notifier on failure after complete_formation() Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 053/148] ALSA: hda/realtek - ALC292 dock fix for Thinkpad L450 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 046/148] lib: Fix strnlen_user() to not touch memory after specified maximum Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 065/148] staging: vt6655: device_free_tx_buf use only ieee80211_tx_status_irqsafe Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 008/148] KVM: MMU: fix CR4.SMEP=1, CR0.WP=0 with shadow pages Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 033/148] iio: adc: cc10001: Fix incorrect use of power-up/power-down register Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 034/148] iio: adc: cc10001: Add delay before setting START bit Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 040/148] hwmon: (tmp401) Do not auto-detect chip on I2C address 0x37 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 049/148] ALSA: usb-audio: Add quirk for MS LifeCam Studio Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 009/148] KVM: MMU: fix smap permission check Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 023/148] Revert "libceph: clear r_req_lru_item in __unregister_linger_request()" Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 050/148] ALSA: hda - Add Conexant codecs CX20721, CX20722, CX20723 and CX20724 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 045/148] brcmfmac: avoid null pointer access when brcmf_msgbuf_get_pktid() fails Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 035/148] iio: adc: cc10001: Fix regulator_get_voltage() return value check Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 060/148] ASoC: wm8960: fix "RINPUT3" audio route error Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 022/148] libceph: request a new osdmap if lingering request maps to no osd Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 025/148] xen/events: dont bind non-percpu VIRQs with percpu chip Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 004/148] iommu/arm-smmu: Fix sign-extension of upstream bus addresses at stage 1 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 057/148] ASoC: mc13783: Fix wrong mask value used in mc13xxx_reg_rmw() calls Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 024/148] Btrfs: fix racy system chunk allocation when setting block group ro Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 051/148] ALSA: hda - Add headphone quirk for Lifebook E752 Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 007/148] x86/fpu: Disable XSAVES* support for now Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 064/148] staging: vt6656: use ieee80211_tx_info to select packet type. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 056/148] ALSA: hda - Fix noise on AMD radeon 290x controller Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 003/148] iommu/amd: Fix bug in put_pasid_state_wait Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 032/148] iio: adc: cc10001: Fix the channel number mapping Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:00 +0200
  [PATCH 4.0 015/148] omfs: fix sign confusion for bitmap loop counter Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:10 +0200
  [PATCH 4.0 018/148] lguest: fix out-by-one error in address checking. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:10 +0200
  [PATCH 4.0 002/148] fs_pin: Allow for the possibility that m_list or s_list go unused. Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:10 +0200
  [PATCH 4.0 016/148] xfs: xfs_attr_inactive leaves inconsistent attr fork state behind Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:10 +0200
  [PATCH 4.0 014/148] fs, omfs: add NULL terminator in the end up the token list Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:10 +0200
  [PATCH 4.0 017/148] xfs: xfs_iozero can return positive errno Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:10 +0200
  [PATCH 4.0 019/148] ovl: dont remove non-empty opaque directory Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2015-06-03 15:10 +0200
  Re: [PATCH 4.0 000/148] 4.0.5-stable review Shuah Khan <shuahkh@osg.samsung.com> - 2015-06-03 19:00 +0200

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